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448
BCMSN Quick Reference Sheets
BC
MS
N Q
uic
k
Refe
ren
ce S
heets
Th
e E
vo
lvin
g N
etw
ork
Mo
del
Th
e H
iera
rch
ical D
esig
n M
od
el
Cis
co S
yste
ms
has
used
the
thre
e-le
vel
Hie
rarc
hica
l Des
ign
Mod
el
for
year
s. T
his
olde
r m
odel
pro
vide
d a
high
-lev
el id
ea o
f ho
w a
rel
iabl
e ne
twor
k co
uld
be c
once
ived
, but
w
as la
rgel
y co
ncep
tual
bec
ause
it d
idn’
t pr
ovid
e sp
ecifi
c gu
idan
ce.
Thi
s si
mpl
e dr
awin
g ill
ustr
ates
how
the
thre
e-la
yer
mod
el m
ight
hav
e be
en b
uilt
out
. A
dist
ribu
tion
Lay
er 3
sw
itch
wou
ld b
e us
ed fo
r ea
ch b
uild
ing
on c
ampu
s, ty
ing
toge
ther
th
e ac
cess
-sw
itch
es o
n th
e flo
ors.
The
cor
e sw
itch
es w
ould
link
the
var
ious
bui
ldin
gs
toge
ther
.
The
laye
rs b
reak
up
a ne
twor
k in
the
fol
low
ing
way
:•
Acc
ess
laye
r
—E
nd s
tati
ons
atta
ch t
o V
LA
Ns.
—C
lient
s at
tach
to
swit
ch p
orts
—V
LA
N a
ssig
ned/
broa
dcas
t do
mai
ns e
stab
lishe
d
—B
uilt
usi
ng lo
w-c
ost
port
s
—Si
mpl
e qu
alit
y of
ser
vice
(Q
oS)
polic
ies
appl
ied
•
Dis
trib
utio
n la
yer
—In
term
edia
te d
evic
es r
oute
and
app
ly p
olic
ies.
—V
LA
Ns
term
inat
ed; r
outi
ng is
don
e be
twee
n th
em
—Po
licie
s ap
plie
d, s
uch
as
rout
e se
lect
ion
acce
ss li
sts
QoS
•
Cor
e la
yer
—B
ackb
one
prov
ides
hig
h-sp
eed
path
bet
wee
n di
stri
buti
on e
lem
ents
.—
Dis
trib
utio
n de
vice
s in
terc
onne
cted
—H
igh
spee
d (t
here
’s pl
enty
of
traf
fic)
—N
o po
licie
s (t
ough
eno
ugh
to k
eep
up)
Lat
er v
ersi
ons
of t
his
mod
el s
how
ed r
edun
dant
dis
trib
utio
n an
d co
re d
evic
es a
nd c
on-
nect
ions
to
mak
e th
e m
odel
mor
e fa
ult
tole
rant
. A s
et o
f di
stri
buti
on d
evic
es a
nd t
heir
ac
com
pany
ing
acce
ss la
yer
swit
ches
wer
e ca
lled
a sw
itch
blo
ck.
Pro
ble
ms w
ith
th
e H
iera
rch
ical
Desig
n M
od
el
Thi
s ea
rly
mod
el w
as a
goo
d st
arti
ng p
oint
, but
it f
aile
d to
add
ress
key
issu
es, s
uch
as•
Whe
re d
o w
irel
ess
devi
ces
fit in
?•
How
sho
uld
Inte
rnet
acc
ess
and
secu
rity
be
prov
isio
ned?
•H
ow s
houl
d re
mot
e ac
cess
, suc
h as
dia
lup
or v
irtu
al p
riva
te n
etw
ork
(VPN
), b
e ac
coun
ted
for?
•W
here
sho
uld
wor
kgro
up a
nd e
nter
pris
e se
rvic
es b
e lo
cate
d?
En
terp
rise C
om
po
sit
e N
etw
ork
Mo
del
The
Cis
co n
ewer
mod
el, t
he e
nter
pris
e co
mpo
site
mod
el, i
s si
gnifi
cant
ly m
ore
com
plex
an
d at
tem
pts
to a
ddre
ss t
he m
ajor
sho
rtco
min
g of
the
hie
rarc
hica
l mod
el b
y ex
pand
ing
the
olde
r ve
rsio
n an
d m
akin
g sp
ecifi
c re
com
men
dati
ons
abou
t ho
w a
nd w
here
cer
tain
ne
twor
k fu
ncti
ons
shou
ld b
e im
plem
ente
d. T
his
mod
el is
bas
ed o
n th
e pr
inci
ples
de
scri
bed
in t
he C
isco
Arc
hite
ctur
e fo
r V
oice
, Vid
eo, a
nd I
nteg
rate
d D
ata
(AV
VID
).
Cor
e
Dis
trib
utio
n
Acc
ess
0910_BCMSNssf.fm Page 448 Tuesday, September 9, 2003 8:20 AM
The Evolving Network Model
449
The
ent
erpr
ise
com
posi
te m
odel
is b
roke
n up
into
thr
ee la
rge
sect
ions
:•
Ent
erpr
ise
cam
pus
•E
nter
pris
e ed
ge•
Serv
ice
prov
ider
edg
e—T
he d
iffe
rent
pub
lic n
etw
orks
tha
t ar
e at
tach
ed
The
firs
t se
ctio
n, t
he e
nter
pris
e ca
mpu
s, lo
oks
like
the
old
hier
arch
ical
mod
el w
ith
som
e ad
ded
deta
ils. I
t fe
atur
es s
ix s
ecti
ons:
1.C
ampu
s ba
ckbo
ne—
Lik
e th
e ol
d “c
ore”
2.B
uild
ing
dist
ribu
tion
3.B
uild
ing
acce
ss4.
Man
agem
ent
5.E
dge
dist
ribu
tion
—A
dis
trib
utio
n la
yer
out
to t
he W
AN
6.Se
rver
far
m—
For
ente
rpri
se s
ervi
ces
Rem
ote
Acc
ess
E-C
om
mer
ce
Inte
rnet
WA
N
Man
agem
ent
Cam
pus
Bac
kbon
e
21
43
65
87
109
UTI
LST
AT
DU
PLX
SPEE
DSYST
EM RPS
MO
DE
1112
CATA
LYST
3550
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
1st F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
2nd F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
3rd F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
4th F
loor
FAN
STAT
US
1 2 3 4 5 6 7 8 9
Pow
er S
uppl
y 1
Pow
er S
uppl
y 2
Catalyst6500
SER
IES
FAN
STAT
US
1 2 3 4 5 6 7 8 9
Pow
er S
uppl
y 1
Pow
er S
uppl
y 2
Catalyst6500
SER
IES
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
1st F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
2nd F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
3rd
Flo
or
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
4th F
loor
Bui
ldin
g A
cces
s
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
1st F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
2nd
Flo
or
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
3rd F
loor
SYST
RPS
STR
TD
UPL
XSPE
EDU
TIL
MO
DE
Catalyst2950
SER
IES
3 4
5 6
7 8
9 10
11 12
1
1
2
2
4th F
loor
Ser
ver
Farm
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
IDC
Lega
cyF
ile &
Prin
tD
atab
ase
E-M
ail
IDC
DN
SIDC
Dire
ctor
yE
dge
Dis
trib
utio
n
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
21
43
65
87
109
UTI
L
STAT
DU
PLX
SPEE
DSYST
EMRPS
MO
DE
1112
CATA
LYST
3550
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K10
0 M
bps
ACT
LIN
K10
0 M
bps
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Inte
rnal
Rou
ter
Inte
rnal
Fire
wal
l
DM
Z F
irew
all
Web
Dat
abas
eI
DC
App
Ser
ver
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K10
0 M
bps
ACT
LIN
K10
0 M
bps
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Inte
rnet
Rou
ter
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K10
0 M
bps
ACT
LIN
K10
0 M
bps
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Cor
pora
teR
oute
r
Dia
l-In
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K
100
Mbp
s
ACT
LIN
K
100
Mbp
s
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Inte
rnal
Rou
ter
Inte
rnal
Fire
wal
lD
MZ
Fire
wal
l
Cac
hing
Pub
licS
erve
rs
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K
100
Mbp
s
ACT
LIN
K
100
Mbp
s
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Inte
rnet
Rou
ter
W2
W1
W0
CF
AUX
CO
NSO
LE
ACT
LIN
K
100
Mbp
sAC
T
LIN
K
100
Mbp
s
FAST
ETH
ERN
ET 0
/1FA
STET
HER
NET
0/0
POW
ERSY
S
CIS
CO
3745
-IO-2
FE
ETM
AIM
0N
PAAI
M1
Inte
rnal
Rou
ter
Fire
wal
lV
PN
IDS
21
43
65
87
109
UTI
LST
AT
DU
PLX
SPEE
DSYST
EM RPS
MO
DE
1112
CATA
LYST
3550
Inte
rnet
ATM
Fram
e R
elay
Ser
vice
Pro
vid
er E
dg
eE
nte
rpri
se E
dg
eE
nte
rpri
se C
amp
us
PP
P PS
TN
Bui
ldin
g A
cces
sB
uild
ing
Acc
ess
Bui
ldin
g D
istr
ibut
ion
Bui
ldin
g D
istr
ibut
ion
Bui
ldin
g D
istr
ibut
ion
0910_BCMSNssf.fm Page 449 Tuesday, September 9, 2003 8:20 AM
450
BCMSN Quick Reference Sheets
The
ent
erpr
ise
edge
det
ails
the
con
nect
ions
fro
m t
he c
ampu
s to
the
wid
e ar
ea a
nd
incl
udes
the
fol
low
ing:
1.E
-com
mer
ce2.
Inte
rnet
con
nect
ivit
y3.
Rem
ote
acce
ss—
Dia
l and
VPN
4.W
ide-
area
net
wor
k (W
AN
)—In
tern
al li
nks
The
ser
vice
pro
vide
r ed
ge is
just
a li
st o
f th
e pu
blic
net
wor
ks t
hat
faci
litat
e w
ide-
area
co
nnec
tivi
ty:
1.In
tern
et s
ervi
ce p
rovi
der
(ISP
)2.
Publ
ic S
wit
ched
Tel
epho
ne N
etw
ork
(PST
N)—
Dia
lup
3.Fr
ame
Rel
ay, A
sync
hron
ous
Tra
nsfe
r M
ode
(AT
M),
and
Poi
nt-t
o-Po
int
Prot
ocol
(P
PP)—
Priv
ate
conn
ecti
vity
Mu
ltilayer
Sw
itch
ing
Co
mp
ari
ng
Devic
es
Lay
er 2
sw
itch
es
•M
AC
add
ress
lear
ning
•H
ardw
are-
base
d br
idge
•Fo
rwar
ding
/filt
erin
g ba
sed
on M
AC
add
ress
•Sp
anni
ng t
ree
to a
void
loop
s•
Wir
e sp
eed,
low
late
ncy
•Sc
alab
le
Rou
ters
•U
nder
stan
d ne
twor
k st
ruct
ure
•Fo
rwar
d al
ong
best
pat
h ba
sed
on L
ayer
3 a
ddre
ss•
Can
app
ly p
olic
ies
to t
raffi
c•
Secu
rity
•Q
ualit
y of
ser
vice
•R
outi
ng•
Low
er s
peed
, hig
her
late
ncy
Lay
er 3
Sw
itch
es
•H
ardw
are-
base
d ro
utin
g•
Prov
ide
flow
acc
ount
ing
•U
nder
stan
d ne
twor
k st
ruct
ure
•Fo
rwar
d al
ong
best
pat
h•
Can
app
ly p
olic
ies
to t
raffi
c•
Secu
rity
•Q
ualit
y of
ser
vice
•R
outi
ng•
Wir
e sp
eed,
low
late
ncy
Co
mp
ari
ng
Eth
ern
et
Vers
ion
s
All
vers
ions
of
Eth
erne
t ha
ve f
eatu
res
in c
omm
on:
•Sa
me
fram
e de
finit
ion
and
field
val
ues
•Sa
me
MA
C a
ddre
ss s
truc
ture
Eth
erne
t
•10
Mbp
s us
ing
Man
ches
ter
enco
ding
, hal
f or
ful
l dup
lex
•L
inks
ext
end
100
m, t
ypic
ally
on
CA
T-5
cabl
e•
Not
typ
ical
ly d
eplo
yed
toda
y
Fast
Eth
erne
t
•10
0 M
bps
usin
g 4B
5B e
ncod
ing,
hal
f or
ful
l dup
lex
•L
inks
ext
end
100
m o
n C
AT-
5 or
CA
T-6
cabl
e•
Use
d fo
r cl
ient
att
achm
ent
toda
y
Gig
abit
Eth
erne
t
•10
00 M
bps
(1 G
bps)
usi
ng 8
B10
B e
ncod
ing,
ful
l dup
lex
•10
00B
ase-
T s
uppo
rts
100
m li
nks
usin
g C
AT-
5 or
CA
T-6
cabl
e•
1000
Bas
e-SX
sup
port
s 55
0 m
link
s us
ing
mul
tim
ode
fiber
•10
00B
ase-
LX
sup
port
s 10
km
link
s us
ing
sing
le-m
ode
fiber
•U
sed
to a
ggre
gate
tra
ffic
to d
istr
ibut
ion
or c
ore
swit
ches
tod
ay
10G
igab
it E
ther
net
•10
,000
Mbp
s (1
0Gbp
s), f
ull d
uple
x on
ly•
Supp
orts
mul
tim
ode
(les
s th
an 3
00 m
) an
d si
ngle
-mod
e fib
er (
up t
o 40
km
)•
Not
com
mon
tod
ay; s
omet
imes
use
d to
agg
rega
te t
raffi
c in
bac
kbon
e
Lon
g R
ange
Eth
erne
t
•5–
15 M
bps
•L
inks
use
ver
y hi
gh d
ata
rate
dig
ital
sub
scri
ber
line
(VD
SL)
mod
ulat
ion
to e
xten
d 50
0 fe
et o
n C
AT-
1/2/
3•
Use
d to
pro
vide
bro
adba
nd in
mul
ti-un
it dw
ellin
gs (a
part
men
ts, o
ffice
bui
ldin
gs, h
otel
s)
0910_BCMSNssf.fm Page 450 Tuesday, September 9, 2003 8:20 AM
VLAN Implementation
451
Met
ro E
ther
net
•U
ses
“dar
k fib
er”
or s
ervi
ce p
rovi
der
•E
ther
net
prin
cipl
es e
xten
ded
into
met
ropo
litan
-are
a ne
twor
k (M
AN
)
Swit
chin
g R
oles
in t
he E
nter
pris
e C
ompo
site
Mod
el
•B
uild
ing
Acc
ess—
Typi
cally
Lay
er 2
sw
itch
es•
Bui
ldin
g D
istr
ibut
ion—
Typi
cally
Lay
er 3
sw
itch
es•
Cam
pus
Bac
kbon
e—L
ayer
2 s
wit
ches
if n
o L
ayer
3 c
apab
iliti
es r
equi
red
•Se
rver
Far
m—
Usu
ally
Lay
er 3
sw
itch
es a
t ac
cess
and
dis
trib
utio
n
Cata
lyst
Sw
itch
Basic
s
CatO
S V
ers
us IO
S
Cat
OS
•L
ayer
2 s
wit
chin
g•
Can
use
MSF
C w
ith
IOS
for
Lay
er 3
(m
ulti
laye
r sw
itch
ing)
func
tion
alit
y•
Foun
d on
Cat
alys
t 40
00 a
nd 6
500
(opt
iona
l)
IOS
•L
ayer
2 a
nd 3
sw
itch
ing
•Po
rts
can
be “
rout
ed”
or “
swit
ched
”•
Foun
d on
Cat
alys
t 29
50 (
Lay
er 2
onl
y), 3
550,
400
0, a
nd 6
500
(opt
iona
l)
Savin
g C
ata
lyst
Files
•T
rivi
al F
ile T
rans
fer
Prot
ocol
(T
FTP)
—To
cop
y IO
S to
TFT
P:
copy
flas
h tf
tp
—To
cop
y IO
S fr
om T
FTP:
copy
tft
p fla
sh
—V
erif
y Fl
ash
cont
ents
:
show
flas
h
—To
sav
e cu
rren
t co
nfigu
rati
on t
o N
VR
AM
:
copy
run
sta
rt
—To
sav
e cu
rren
t co
nfigu
rati
on t
o T
FTP:
copy
run
tft
p
IOS
Tro
ub
lesh
oo
tin
g
Show
•Pr
ovid
es s
naps
hots
of
devi
ce p
erfo
rman
ce•
Low
ove
rhea
d•
Info
rmat
ion
orga
nize
d
Deb
ug
•Pr
ovid
es r
eal-
tim
e di
spla
y of
dev
ice
perf
orm
ance
•H
igh
over
head
•U
ses
show
pro
cess
es
to s
ee p
roce
ssor
uti
lizat
ion
•In
form
atio
n no
t or
gani
zed
•U
ses
serv
ice
tim
esta
mps
deb
ug d
atet
ime
mse
c
to s
ee e
vent
tim
es•
Focu
ses
debu
ggin
g to
min
imiz
e im
pact
VLA
N Im
ple
men
tati
on
Wh
at
Is a
VLA
N?
A V
LA
N is
a lo
gica
l LA
N o
r a
logi
cal s
ubne
t. I
t de
fines
a b
road
cast
dom
ain.
A p
hysi
cal
subn
et is
a g
roup
of d
evic
es s
hari
ng th
e sa
me
phys
ical
wir
e. A
logi
cal s
ubne
t is
a gr
oup
of s
wit
ch p
orts
ass
igne
d to
the
sam
e V
LA
N, r
egar
dles
s of
the
ir p
hysi
cal l
ocat
ion
in a
sw
itch
ed n
etw
ork.
Two
type
s of
VL
AN
s ar
e•
End
-to-
end
VL
AN
—H
osts
in t
he V
LA
N r
esid
e on
sev
eral
dif
fere
nt s
wit
ches
and
ar
e sc
atte
red
thro
ugho
ut t
he n
etw
ork.
Use
d w
hen
host
s ar
e as
sign
ed t
o V
LA
Ns
base
d on
fun
ctio
ns o
r w
orkg
roup
s, r
athe
r th
an p
hysi
cal l
ocat
ion.
VL
AN
s sh
ould
no
t ex
tend
pas
t th
e B
uild
ing
Dis
trib
utio
n su
bmod
ule.
•
Geo
grap
hic
(loc
al) V
LA
N
—H
osts
are
ass
igne
d to
VL
AN
s ba
sed
on th
eir
loca
tion
, su
ch a
s a
floor
in a
bui
ldin
g. A
rou
ter
acco
mpl
ishe
s sh
arin
g of
res
ourc
es b
etw
een
VL
AN
s. T
his
type
is t
ypic
ally
fou
nd in
the
Bui
ldin
g A
cces
s su
bmod
ule.
4th
Flo
or
HR
Dep
artm
ent
ITD
epar
tmen
t
3rd
Flo
or
2nd
Flo
or
1st F
loor
0910_BCMSNssf.fm Page 451 Tuesday, September 9, 2003 8:20 AM
452
BCMSN Quick Reference Sheets
VL
AN
mem
bers
hip
can
be a
ssig
ned
eith
er s
tati
cally
by
port
, or
dyna
mic
ally
by
MA
C
addr
ess
usin
g a
VL
AN
Mem
bers
hip
Polic
y Se
rver
(V
MPS
).
Cre
ati
ng
a V
LA
N in
Glo
bal C
on
fig
Mo
de
(config)#
vlan 12
(config-vlan)#
name MYVLAN
Cre
ati
ng
a V
LA
N in
Data
base M
od
e
#vlan database
(vlan)#
vlan 12 name MYVLAN
Del
ete
a V
LA
N b
y us
ing
the
sam
e co
mm
and
wit
h
no
in f
ront
of
it. Y
ou d
o no
t ne
ed t
o in
clud
e th
e na
me
whe
n de
leti
ng.
Assig
nin
g P
ort
s t
o V
LA
Ns
Whe
n st
atic
ally
ass
igni
ng p
orts
to
VL
AN
s, fi
rst
mak
e it
an
acce
ss p
ort
and
then
ass
ign
the
port
to
a V
LA
N. A
t th
e in
terf
ace
confi
gura
tion
pro
mpt
, typ
e
sssswwwwiiiittttcccchhhhppppoooorrrrtttt mmmmooooddddeeee aaaacccccccceeeessssssss
sssswwwwiiiittttcccchhhhppppoooorrrrtttt aaaacccccccceeeessssssss vvvvllllaaaannnn 11112222
To u
se d
ynam
ic V
LA
N a
ssig
nmen
t, t
he c
omm
ands
are
sim
ilar.
At
inte
rfac
e co
nfigu
rati
on m
ode,
typ
e
sssswwwwiiiittttcccchhhhppppoooorrrrtttt mmmmooooddddeeee aaaacccccccceeeessssssss
sssswwwwiiiittttcccchhhhppppoooorrrrtttt aaaacccccccceeeessssssss vvvvllllaaaannnn ddddyyyynnnnaaaammmmiiiicccc
If u
sing
dyn
amic
, you
mus
t al
so e
nter
the
IP
addr
ess
of t
he V
MPS
ser
ver
at g
loba
l co
nfigu
rati
on m
ode:
vmps server
ip address
Veri
fyin
g V
LA
N C
on
fig
ura
tio
n
To s
ee a
list
of
all t
he V
LA
Ns
and
the
port
s as
sign
ed t
o th
em, u
se t
he c
omm
and
show
vl
an
. To
narr
ow d
own
the
info
rmat
ion
disp
laye
d, y
ou c
an u
se th
ese
keyw
ords
aft
er th
e co
mm
and:
brie
f, id
,
vlan
-num
ber
,
or
nam
e
vlan
-nam
e
.
ASW#
show vlan brief
VLAN Name
Status
Ports
---- -------------------------------- --------- ------------------------------
1 default
active
Fa0/1, Fa0/2, Fa0/3,
Fa0/10,Fa0/11,Fa0/12
20 VLAN0020
active
Fa0/5,Fa0/6,Fa0/7
21 VLAN0021
active
Fa0/8,Fa0/9
1002 fddi-default
active
1003 trcrf-default
active
1004 fddinet-default
active
1005 trbrf-default
active
Oth
er v
erifi
cati
on c
omm
ands
incl
ude
the
follo
win
g:•
show
run
ning
-con
fig in
terf
ace
inte
rfac
e no
.
—U
se to
ver
ify
the
VL
AN
mem
bers
hip
of t
he p
ort:
ASW#
show run interface fa0/5
Building configuration...
Current configuration 64 bytes
interface FastEthernet 0/5
switchport access vlan 20
switchport mode access
•
show
mac
add
ress
-tab
le in
terf
ace
inte
rfac
e no
.
vla
n
vlan
no.
—U
se t
o vi
ew M
AC
ad
dres
ses
lear
ned
thro
ugh
that
por
t fo
r th
e sp
ecifi
ed V
LA
N:
ASW#
show mac address-table interface fa0/1
Mac Address Table
------------------------------------------
Vlan Mac Address Type Ports
---- ----------- ---- -----
1 0030.b656.7c3d DYNAMIC Fa0/1
Total Mac Addresses for this criterion: 1
4th
Flo
or
HR
Dep
artm
ent
ITD
epar
tmen
t
3rd
Flo
or
2nd
Flo
or
1st F
loor
0910_BCMSNssf.fm Page 452 Tuesday, September 9, 2003 8:20 AM
VLAN Implementation
453
•
show
inte
rfac
es
inte
rfac
e no
.
swit
chpo
rt
—U
se t
o se
e de
taile
d in
form
atio
n ab
out
the
port
con
figur
atio
n, s
uch
as e
ntri
es in
the
Adm
inis
trat
ive
Mod
e an
d A
cces
s M
ode
VL
AN
fiel
ds:
ASW#
show interfaces fa0/1 switchport
Name: Fa0/1
Switchport: Enabled
Administrative Mode: dynamic desirable
Operational Mode: static access
Administrative Trunking Encapsulation: negotiate
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Protected: false
Unknown unicast blocked: false
Unknown multicast blocked: false
Broadcast Suppression Level: 100
Multicast Suppression Level: 100
Unicast Suppression Level: 100
Tro
ub
lesh
oo
tin
g V
LA
N Issu
es
The
thr
ee s
teps
in t
roub
lesh
ooti
ng V
LA
N p
robl
ems
are
1.
Che
ck t
he p
hysi
cal c
onne
ctiv
ity
—M
ake
sure
the
cab
le is
goo
d an
d th
e ne
twor
k ad
apte
r an
d sw
itch
por
t ar
e bo
th g
ood.
Che
ck t
he p
ort’s
link
LE
D.
2.
Che
ck th
e sw
itch
con
figur
atio
n
—If
you
see
fram
e ch
eck
sequ
ence
(FC
S) e
rror
s or
la
te c
ollis
ions
, sus
pect
a d
uple
x m
ism
atch
. Als
o ch
eck
confi
gure
d sp
eed
on b
oth
ends
of
the
link.
Inc
reas
ing
colli
sion
s m
ight
mea
n an
ove
rloa
ded
link,
suc
h as
w
ith
a br
oadc
ast
stor
m.
3.
Che
ck th
e V
LA
N c
onfig
urat
ion
—If
two
host
s ca
n’t c
omm
unic
ate,
mak
e su
re th
ey
are
both
in t
he s
ame
VL
AN
. If
a ho
st c
an’t
conn
ect
to a
sw
itch
, mak
e su
re t
he
host
and
the
sw
itch
are
in t
he s
ame
VL
AN
.
VLA
N T
run
kin
g
A
trun
k
is a
link
tha
t ca
rrie
s tr
affic
for
mor
e th
an o
ne V
LA
N. T
runk
s m
ulti
plex
tra
ffic
from
mul
tipl
e V
LA
Ns.
Tru
nks
conn
ect
swit
ches
and
allo
w p
orts
on
mul
tipl
e sw
itch
es
to b
e as
sign
ed t
o th
e sa
me
VL
AN
.
Two
met
hods
of
iden
tify
ing
VL
AN
s ov
er t
runk
link
s ar
e•
ISL
(In
ter-
Swit
ch L
ink)
—
Cis
co p
ropr
ieta
ry; e
ncap
sula
tes
the
orig
inal
fra
me
in a
he
ader
tha
t co
ntai
ns V
LA
N in
form
atio
n. I
s pr
otoc
ol-i
ndep
ende
nt; c
an id
enti
fy
Cis
co D
isco
very
Pro
toco
l (C
DP)
and
bri
dge
prot
ocol
dat
a un
it (
BPD
U)
fram
es.
•
802.
1Q
—St
anda
rds-
base
d; t
ags
the
fram
es (
inse
rts
a fie
ld in
to t
he o
rigi
nal f
ram
e im
med
iate
ly a
fter
the
sou
rce
MA
C a
ddre
ss fi
eld)
; sup
port
s E
ther
net
and
Toke
n R
ing
netw
orks
.W
hen
a fr
ame
com
es in
to a
sw
itch
por
t, t
he f
ram
e is
tag
ged
inte
rnal
ly w
ithi
n th
e sw
itch
wit
h th
e V
LA
N n
umbe
r of
the
por
t. W
hen
it r
each
es t
he o
utgo
ing
port
, tha
t in
tern
al t
ag is
rem
oved
. If
the
exit
por
t is
a t
runk
por
t, t
hen
its
VL
AN
is id
enti
fied
eith
er in
the
ISL
enc
apsu
lati
on o
r th
e 80
2.1Q
tag
. The
sw
itch
on
the
othe
r en
d of
the
tr
unk
rem
oves
the
ISL
or 8
02.1
Q in
form
atio
n, c
heck
s th
e V
LAN
of t
he fr
ame,
and
add
s th
e in
tern
al ta
g. If
the
exit
port
is a
use
r po
rt, t
hen
the
orig
inal
fram
e is
sen
t out
unc
hang
ed,
mak
ing
the
use
of V
LAN
s tr
ansp
aren
t to
the
user
.If
a n
on-t
runk
ing
port
rec
eive
s an
ISL-
enca
psul
ated
fram
e, th
e fr
ame
is d
ropp
ed. A
lso,
if th
e IS
L he
ader
and
foot
er c
ause
the
MT
U s
ize
to b
e ex
ceed
ed, i
t mig
ht b
e co
unte
d as
an
erro
r.If
a n
on-t
runk
ing
port
rec
eive
s an
802
.1Q
fram
e, th
e so
urce
and
des
tinat
ion
MA
C
addr
esse
s ar
e re
ad, t
he ta
g fie
ld is
igno
red,
and
the
fram
e is
sw
itche
d no
rmal
ly a
t Lay
er 2
.
Co
nfi
gu
rin
g a
Tru
nk L
ink
Port
s ca
n be
com
e tr
unk
port
s ei
ther
by
stat
ic c
onfig
urat
ion
or d
ynam
ic n
egot
iatio
n us
ing
Dyn
amic
Tru
nkin
g Pr
otoc
ol (D
TP)
. A s
witc
h po
rt c
an b
e in
one
of fi
ve D
TP
mod
es:
•
Acc
ess
—T
he p
ort
is a
use
r po
rt a
nd c
anno
t be
a t
runk
.•
Tru
nk
—T
he p
ort
is a
tru
nk a
nd n
egot
iate
s tr
unki
ng w
ith
the
port
on
the
othe
r en
d of
the
link
.
VLA
N 1
0O
nly
VLA
N 2
0O
nly
VLA
N 2
0O
nly
VLA
N 1
0O
nly
Trun
k C
arrie
sV
LAN
s 1,
10,
and
20
0910_BCMSNssf.fm Page 453 Tuesday, September 9, 2003 8:20 AM
454
BCMSN Quick Reference Sheets
•
Non
nego
tiat
e
—W
hen
this
key
wor
d is
add
ed, t
he p
ort
is a
tru
nk a
nd d
oes
not
do
DT
P ne
goti
atio
n w
ith
the
othe
r si
de o
f th
e lin
k.•
Dyn
amic
Des
irab
le
—A
ctiv
ely
nego
tiat
es t
runk
ing
wit
h th
e ot
her
side
of
the
link.
B
ecom
es a
tru
nk if
the
por
t on
the
oth
er s
wit
ch is
set
to
trun
k
,
dyna
mic
desi
rabl
e
, or
dyna
mic
auto
mod
e.•
Dyn
amic
Aut
o
—Pa
ssiv
ely
wai
ts t
o be
con
tact
ed b
y th
e ot
her
swit
ch. B
ecom
es a
tr
unk
if t
he o
ther
end
is s
et t
o
trun
k
or
dyna
mic
des
irab
le
mod
e.C
onfig
ure
a po
rt f
or t
runk
ing
at t
he in
terf
ace
confi
gura
tion
mod
e:
sssswwwwiiiittttcccchhhhppppoooorrrrtttt mmmmooooddddeeee {{{{ddddyyyynnnnaaaammmmiiiicccc {{{{aaaauuuuttttoooo
|
ddddeeeessssiiiirrrraaaabbbblllleeee}}}}
|
ttttrrrruuuunnnnkkkk}}}}
If d
ynam
ic m
ode
is u
sed,
DT
P ne
goti
ates
tru
nkin
g st
ate
and
enca
psul
atio
n. I
f tr
unk
mod
e is
use
d, y
ou m
ust
spec
ify
enca
psul
atio
n:
sssswwwwiiiittttcccchhhhppppoooorrrrtttt ttttrrrruuuunnnnkkkk eeeennnnccccaaaappppssssuuuullllaaaattttiiiioooonnnn {{{{iiiissssllll
|
ddddooootttt1111qqqq
|
nnnneeeeggggoooottttiiiiaaaatttteeee}}}}
Nati
ve V
LA
N w
ith
802.1
Q
If y
ou a
re u
sing
802
.1Q
, you
mus
t sp
ecif
y a
nati
ve V
LA
N f
or t
he t
runk
link
wit
h th
is
com
man
d:
switchport trunk native vlan
vlan no.
Fram
es f
rom
the
nat
ive
VL
AN
are
sen
t ov
er t
he t
runk
link
unt
agge
d. I
t is
the
VL
AN
th
e po
rt w
ould
be
in if
it w
ere
not
a tr
unk
and
mus
t m
atch
on
both
sid
es o
f th
e tr
unk
link.
VL
AN
1 is
the
def
ault
nat
ive
VL
AN
for
all
port
s.
VLA
N M
ap
pin
g
ISL
tru
nkin
g re
cogn
izes
onl
y V
LA
Ns
num
bere
d 1–
1001
, but
802
.1Q
can
use
VL
AN
s 0–
4094
. If
you
are
usin
g bo
th I
SL a
nd 8
02.1
Q in
you
r ne
twor
k an
d ha
ve V
LA
Ns
num
bere
d ab
ove
1001
, you
hav
e to
map
the
802
.1Q
VL
AN
s to
ISL
num
bers
. Som
e ru
les
abou
t m
appi
ng V
LA
Ns
are
as f
ollo
ws:
•Y
ou c
an c
onfig
ure
only
eig
ht m
appi
ngs.
•M
appi
ngs
are
loca
l to
the
swit
ch—
The
sam
e m
appi
ngs
mus
t be
con
figur
ed o
n al
l sw
itch
es in
the
net
wor
k.•
You
can
map
onl
y to
Eth
erne
t IS
L V
LA
Ns.
•T
he 8
02.1
Q V
LA
Ns
wit
h th
e sa
me
num
ber
as m
appe
d IS
L V
LA
Ns
are
bloc
ked.
(F
or e
xam
ple,
you
map
802
.1Q
VL
AN
150
0 to
ISL
VL
AN
150
, and
the
n 80
2.1Q
V
LA
N 1
50 is
blo
cked
on
that
sw
itch
.)•
Don
’t m
ap t
he 8
02.1
Q n
ativ
e V
LA
N.
VLA
Ns A
llo
wed
on
th
e T
run
k
By
defa
ult,
a t
runk
car
ries
tra
ffic
for
all V
LA
Ns.
You
can
cha
nge
that
beh
avio
r fo
r a
part
icul
ar t
runk
link
by
givi
ng t
he f
ollo
win
g co
mm
and
at t
he in
terf
ace
confi
g m
ode:
switchport trunk allowed vlan
vlans
Mak
e su
re t
hat
both
sid
es o
f a
trun
k lin
k al
low
the
sam
e V
LA
Ns.
Veri
fyin
g a
Tru
nk L
ink
You
can
use
tw
o co
mm
ands
to
veri
fy y
our
trun
k co
nfigu
rati
on:
sssshhhhoooowwww rrrruuuunnnnnnnniiiinnnngggg----ccccoooonnnnffffiiiigggg
show interfaces [interface no.] switchport
| trunk
Usi
ng t
he t
runk
key
wor
d w
ith
the
show
inte
rfac
es c
omm
and
give
s in
form
atio
n ab
out
the
trun
k lin
k:ASW# show interfaces fastethernet 0/1 trunk
Port Mode Encapsulation Status Native vlan
Fa0/1 desirable n-802.1q trunking 1
Port Vlans allowed on trunk
Fa0/1 1-150
<further output omitted>
802.1
Q T
un
nels
Tunn
elin
g is
a w
ay t
o se
nd 8
02.1
Q-t
agge
d fr
ames
acr
oss
a fo
reig
n ne
twor
k (s
uch
as a
se
rvic
e pr
ovid
er’s
netw
ork)
and
sti
ll pr
eser
ve t
he o
rigi
nal 8
02.1
Q t
ag. T
he s
ervi
ce p
ro-
vide
r (S
P) c
onfig
ures
its
end
of t
he t
runk
link
as
a tu
nnel
por
t an
d as
sign
s a
VL
AN
to
carr
y yo
ur t
raffi
c w
ithi
n it
s ne
twor
k. T
he S
P sw
itch
the
n ad
ds a
sec
ond
802.
1Q t
ag t
o ea
ch fr
ame
that
cam
e in
the
tunn
el p
ort.
Oth
er s
wit
ches
in th
e SP
net
wor
k se
e on
ly th
is
seco
nd t
ag, a
nd d
on’t
read
the
ori
gina
l tag
. Whe
n th
e fr
ame
exit
s th
e SP
net
wor
k, t
he
extr
a ta
g is
rem
oved
, lea
ving
the
orig
inal
802
.1Q
tag
to b
e re
ad b
y th
e re
ceiv
ing
swit
ch
in y
our
netw
ork.
DA
SA
ET
YP
ED
ata
802.
1QTr
unk
Por
t.1
Q A
cces
sP
ort
V=
900
DA
SA
ET
YP
ED
ata
ET
YP
E80
2.1Q
802.
1Q
DA
SA
Dat
aE
TY
PE
802.
1QIS
L
DA
SA
Dat
aE
TY
PE
802.
1QV
=5
Acc
ess
Q E
dge
V=
900
Sec
ond
Tag S
econ
d Ta
gC
ore
Cus
tom
erIS
P L
2 C
ore
802.
1Q o
r IS
LTr
unk
Por
t80
2.1Q
or
ISL
Trun
k P
ort
Si
0910_BCMSNssf.fm Page 454 Tuesday, September 9, 2003 8:20 AM
VLAN Implementation 455
Layer
2 P
roto
co
l Tu
nn
elin
gIf
a s
ervi
ce p
rovi
der
sepa
rate
s se
ctio
ns o
f yo
ur n
etw
ork,
you
can
use
Lay
er 2
pro
toco
l tu
nnel
ing
to tu
nnel
CD
P, S
pann
ing
Tre
e Pr
otoc
ol (S
TP)
, and
VL
AN
Tru
nkin
g Pr
otoc
ol
(VT
P) fr
ames
acr
oss
the
SP’s
clou
d. T
his
is c
alle
d G
ener
ic B
ridg
e PD
U T
unne
ling
(GB
PT).
Fram
es f
rom
the
pre
viou
sly
men
tion
ed c
ontr
ol p
roto
cols
are
enc
apsu
late
d as
the
y en
ter
the
SP’s
net
wor
k on
a t
unne
l por
t, a
nd d
e-en
caps
ulat
ed w
hen
they
exi
t th
at n
etw
ork.
Tro
ub
lesh
oo
tin
g T
run
kin
g•
Bot
h si
des
of t
he li
nk in
the
cor
rect
tru
nkin
g m
ode?
•Sa
me
trun
k en
caps
ulat
ion
on b
oth
side
s?•
If 8
02.1
Q, s
ame
nati
ve V
LA
N o
n bo
th s
ides
?
VLA
N T
run
kin
g P
roto
co
l V
LA
N T
runk
ing
Prot
ocol
(V
TP)
run
s ov
er t
runk
link
s an
d sy
nchr
oniz
es t
he V
LA
N
data
base
s of
all
swit
ches
in th
e V
TP
dom
ain.
A V
TP
dom
ain
is a
n ad
min
istr
ativ
e gr
oup.
A
ll sw
itch
es w
ithi
n th
at g
roup
mus
t ha
ve t
he s
ame
VT
P do
mai
n na
me
confi
gure
d, o
r th
ey w
ill n
ot s
ynch
roni
ze d
atab
ases
.V
TP
wor
ks b
y us
ing
confi
gura
tion
rev
isio
n nu
mbe
rs a
nd V
TP
adve
rtis
emen
ts:
•A
ll sw
itch
es s
end
out
VT
P ad
vert
isem
ents
eve
ry fi
ve m
inut
es o
r w
hen
a ch
ange
to
the
VL
AN
dat
abas
e ha
ppen
s (a
VL
AN
is c
reat
ed, d
elet
ed, o
r re
nam
ed.)
•V
TP
adve
rtis
emen
ts c
onta
in a
con
figur
atio
n re
visi
on n
umbe
r. T
his
num
ber
is
incr
ease
d by
1 f
or e
very
VL
AN
cha
nge.
•W
hen
a sw
itch
rec
eive
s a
VT
P ad
vert
isem
ent,
it c
ompa
res
the
confi
gura
tion
re
visi
on n
umbe
r ag
ains
t th
e on
e in
its
VL
AN
dat
abas
e.•
If t
he n
ew n
umbe
r is
hig
her,
the
swit
ch o
verw
rite
s it
s da
taba
se w
ith
the
new
V
LA
N in
form
atio
n an
d fo
rwar
ds t
he in
form
atio
n to
its
neig
hbor
sw
itch
es.
•If
the
num
ber
is t
he s
ame,
the
sw
itch
igno
res
the
adve
rtis
emen
t.•
If t
he n
ew n
umbe
r is
low
er, t
he s
wit
ch r
eplie
s w
ith
the
mor
e up
-to-
date
in
form
atio
n co
ntai
ned
in it
s ow
n da
taba
se.
VT
P S
wit
ch
Ro
les
A V
TP
swit
ch c
an b
e•
A s
erve
r—T
he d
efau
lt. S
erve
rs c
an c
reat
e, d
elet
e, a
nd r
enam
e V
LA
Ns.
The
y or
igin
ate
both
per
iodi
c an
d tr
igge
red
VT
P ad
vert
isem
ents
and
syn
chro
nize
the
ir d
atab
ases
w
ith
othe
r sw
itch
es in
the
dom
ain.
•A
clie
nt—
Clie
nts
cann
ot m
ake
VL
AN
cha
nges
. The
y or
igin
ate
peri
odic
VT
P ad
vert
isem
ents
and
syn
chro
nize
thei
r da
taba
ses
with
oth
er s
witc
hes
in th
e do
mai
n.
•T
rans
pare
nt—
Can
cre
ate,
del
ete,
and
ren
ame
VL
AN
s, b
ut it
s V
LA
Ns
are
loca
l on
ly. D
oes
not
orig
inat
e ad
vert
isem
ents
; doe
s no
t sy
nchr
oniz
e it
s da
taba
se w
ith
any
othe
r sw
itch
es. I
t fo
rwar
ds V
TP
adve
rtis
emen
ts o
ut it
s tr
unk
links
, how
ever
.
VT
P P
run
ing
Rec
all t
hat,
by
defa
ult,
sw
itch
es fl
ood
broa
dcas
ts, m
ulti
cast
s, a
nd u
nkno
wn
unic
asts
ac
ross
tru
nk li
nks.
Sup
pose
a h
ost
in V
LA
N 1
0 on
Sw
itch
B s
ends
a b
road
cast
. Hos
ts
in V
LA
N 1
0 on
Sw
itch
C n
eed
to s
ee t
hat
broa
dcas
t, b
ut S
wit
ch A
has
no
port
s in
V
LA
N 1
0, s
o it
just
dro
ps t
he b
road
cast
tra
ffic.
Ena
blin
g V
TP
Prun
ing
caus
es t
he s
wit
ch t
o ke
ep t
rack
of
VL
AN
por
t as
sign
men
ts in
it
s do
wns
trea
m s
wit
ches
. The
sw
itch
the
n se
nds
only
floo
ded
traf
fic o
n tr
unks
tow
ard
swit
ches
tha
t ha
ve p
orts
ass
igne
d to
the
VL
AN
ori
gina
ting
the
tra
ffic.
It
prun
es fl
oode
d tr
affic
fro
m a
ll o
ther
tru
nks.
VT
P Pr
unin
g in
crea
ses
the
avai
labl
e ba
ndw
idth
by
prev
enti
ng u
nnec
essa
ry t
raffi
c on
tru
nk li
nks.
Two
vers
ions
of
VT
P ex
ist—
Ver
sion
1 a
nd V
ersi
on 2
. To
use
Ver
sion
2, a
ll sw
itch
es in
th
e do
mai
n m
ust
be c
apab
le o
f us
ing
it. C
onfig
ure
one
serv
er f
or V
ersi
on 2
, and
the
in
form
atio
n is
pro
paga
ted
thro
ugh
VT
P. V
ersi
on 2
has
the
fol
low
ing
adde
d fe
atur
es:
•It
sup
port
s To
ken
Rin
g V
LA
Ns.
•T
rans
pare
nt s
wit
ches
pas
s al
ong
mes
sage
s fr
om b
oth
vers
ions
of
VT
P.•
Con
sist
ency
che
cks
are
perf
orm
ed o
nly
whe
n ch
ange
s ar
e co
nfigu
red
thro
ugh
the
com
man
d-lin
e in
terf
ace
(CL
I) o
r Si
mpl
e N
etw
ork
Man
agem
ent
Prot
ocol
(SN
MP)
.
VLA
N 1
0
Sw
itch
A
Sw
itch
BS
witc
h C
0910_BCMSNssf.fm Page 455 Tuesday, September 9, 2003 8:20 AM
456 BCMSN Quick Reference SheetsC
on
fig
uri
ng
VT
PV
TP
confi
gura
tion
is d
one
at t
he g
loba
l con
fig m
ode.
To
confi
gure
the
sw
itch
’s V
TP
mod
e, t
ype
vvvvttttpppp {{{{sssseeeerrrrvvvveeeerrrr
| cccclllliiiieeeennnntttt
| ttttrrrraaaannnnssssppppaaaarrrreeeennnntttt}}}}
To c
onfig
ure
the
VT
P do
mai
n na
me,
typ
evtp domain name
To c
onfig
ure
a V
TP
pass
wor
d (a
ll sw
itch
es in
the
dom
ain
mus
t us
e th
e sa
me
pass
-w
ord)
, typ
evtp password password
To c
onfig
ure
the
swit
ch t
o us
e V
TP
Ver
sion
2, t
ype
vvvvttttpppp vvvv2222----mmmmooooddddeeee
To e
nabl
e pr
unin
g, t
ype
vvvvttttpppp pppprrrruuuunnnniiiinnnngggg
To s
peci
fy w
hich
VL
AN
s ar
e to
be
prun
ed, t
ype
switchport trunk pruning vlan {add
| except
| none
| remove} vlan-list
[,v
lan[,vlan[,,,]]
Veri
fyin
g a
nd
Mo
nit
ori
ng
VT
PTo
get
bas
ic in
form
atio
n ab
out
the
VT
P co
nfigu
rati
on, u
se s
how
vtp
sta
tus.
T
he f
ollo
win
g ex
ampl
e sh
ows
the
defa
ult
sett
ings
:ASW# show vtp status
VTP Version
: 1
Configuration Revision
: 0
Maximum VLANs supported locally
: 1005
Number of existing VLANs
: 5
VTP Operating Mode
: Server
VTP Domain Name
:
VTP Pruning Mode
: Disabled
VTP V2 Mode
: Disabled
VTP Traps Generation
: Disabled
MD5 digest
:
Tro
ub
lesh
oo
tin
g V
TP
Her
e ar
e so
me
com
mon
item
s to
che
ck w
hen
trou
bles
hoot
ing
prob
lem
s w
ith
VT
P:
•M
ake
sure
you
are
trun
king
bet
wee
n th
e sw
itche
s. V
TP
is s
ent o
nly
over
trun
k lin
ks.
•M
ake
sure
the
dom
ain
nam
e m
atch
es o
n bo
th s
wit
ches
(na
me
is c
ase
sens
itiv
e).
•If
the
sw
itch
is n
ot u
pdat
ing
its
data
base
, mak
e su
re it
is n
ot in
tra
nspa
rent
mod
e.•
If u
sing
pas
swor
ds, m
ake
sure
the
y al
l mat
ch. T
o re
mov
e a
pass
wor
d, u
se n
o vt
p pa
ssw
ord.
Ad
din
g a
New
Sw
itch
to
a V
TP
Do
main
Add
ing
a ne
w s
wit
ch in
clie
nt m
ode
does
not
pre
vent
it f
rom
pro
paga
ting
its
inco
rrec
t V
LA
N in
form
atio
n. A
ser
ver
sync
hron
izes
to
a cl
ient
if t
he c
lient
has
the
hig
her
confi
g-ur
atio
n re
visi
on n
umbe
r. Y
ou m
ust
rese
t th
e re
visi
on n
umbe
r ba
ck t
o 0
on t
he n
ew
swit
ch. T
he e
asie
st w
ay t
o do
thi
s is
to
chan
ge t
he d
omai
n na
me.
The
n, c
hang
e it
bac
k to
the
cor
rect
one
and
att
ach
the
swit
ch t
o th
e ne
twor
k.
Un
ders
tan
din
g t
he S
pan
nin
g T
ree
Pro
toco
lSw
itch
es e
ithe
r fo
rwar
d or
filt
er L
ayer
2 f
ram
es. T
he w
ay t
hey
mak
e th
e fo
rwar
ding
/fil
teri
ng d
ecis
ion
can
lead
to
loop
s in
a n
etw
ork
wit
h re
dund
ant
links
. Spa
nnin
g tr
ee is
a
prot
ocol
tha
t de
tect
s po
tent
ial l
oops
and
bre
aks
them
.A
Lay
er 2
sw
itch
is fu
nctio
nally
the
sam
e th
ing
as a
tran
spar
ent b
ridg
e. T
rans
pare
nt b
ridg
es•
Lea
rn M
AC
add
ress
es b
y lo
okin
g at
the
sour
ce a
ddre
ss o
f inc
omin
g fr
ames
. The
y bu
ild a
tabl
e m
appi
ng M
AC
add
ress
to p
ort n
umbe
r.•
Forw
ard
broa
dcas
ts a
nd m
ultic
asts
out
all
port
s ex
cept
the
on
they
cam
e in
on.
(Thi
s is
cal
led
flood
ing.
)•
Forw
ard
unkn
own
unic
asts
out
all
port
s ex
cept
the
one
the
y ca
me
in o
n. A
n un
know
n un
icas
t is
a m
essa
ge b
ound
for
a u
nica
st M
AC
add
ress
tha
t is
not
in t
he
swit
ch’s
tab
le o
f ad
dres
ses
and
port
s.•
Do
not
mak
e an
y ch
ange
s to
the
fra
mes
as
they
for
war
d th
em.
Span
ning
Tre
e Pr
otoc
ol (S
TP)
wor
ks b
y se
lect
ing
a ro
ot b
ridg
e, th
en s
elec
ting
one
loop
-fre
e pa
th fr
om th
e ro
ot b
ridg
e to
eve
ry o
ther
sw
itch.
(ST
P us
es th
e te
rm b
ridg
e be
caus
e it
was
wri
tten
be
fore
ther
e w
ere
switc
hes.
) Con
side
r th
e fo
llow
ing
switc
hed
netw
ork.
Span
ning
tre
e m
ust
sele
ct:
•O
ne r
oot
brid
ge•
One
roo
t po
rt p
er n
on-r
oot
brid
ge•
One
des
igna
ted
port
per
ne
twor
k se
gmen
t
A00
0c.1
111.
0011
B00
0c.2
678.
1010
C00
0c.3
21a.
bcde
000c
.818
1.11
22
E00
0c.2
679.
2222
100
Mbp
s
1000
Mbp
s
10M
bps
10M
bps
100
Mbp
s
100
Mbp
s10
0M
bps
0/1
0/2
D
0910_BCMSNssf.fm Page 456 Tuesday, September 9, 2003 8:20 AM
Understanding the Spanning Tree Protocol 457
Sp
an
nin
g T
ree E
lecti
on
Cri
teri
a1.
Low
est
Roo
t B
ridg
e ID
(B
ID)
2.L
owes
t pa
th c
ost
to t
he r
oot
3.L
owes
t se
nder
Bri
dge
ID4.
Low
est
send
er P
ort
ID (
PID
)B
ridg
e ID
= B
ridg
e pr
iori
ty :
Bri
dge
MA
C a
ddre
ssB
ridg
e pr
iori
ty =
A 2
-byt
e va
lue,
0–6
5,53
5 (0
–FFF
F he
x).
Def
ault
pri
orit
y is
32,
768
(800
0 he
x)Po
rt I
D =
Por
t pr
iori
ty :
port
num
ber
Port
Pri
orit
y =
A 6
-bit
val
ue, 0
–63,
def
ault
is 3
2Pa
th c
ost—
Cum
ulat
ive
valu
e of
the
cos
t of
eac
h lin
k be
twee
n th
e br
idge
and
the
roo
t.
An
old
way
of
calc
ulat
ing
cost
and
a n
ew w
ay o
f ca
lcul
atin
g co
st e
xist
s:
Th
e S
TP
Ele
cti
on
Ro
ot
Bri
dg
e E
lecti
on
Loo
king
at
the
exam
ple,
firs
t se
lect
the
roo
t br
idge
. Ass
ume
each
sw
itch
is u
sing
the
de
faul
t pr
iori
ty.
•Sw
itch
A B
ID =
80-
00-0
0-0c
-11-
11-0
0-11
•Sw
itch
B B
ID =
80-
00-0
0-0c
-26-
78-1
0-10
•Sw
itch
C B
ID =
80-
00-0
0-0c
-32-
1a-b
c-de
•Sw
itch
D B
ID =
80-
00-0
0-0c
-81-
81-1
1-22
•Sw
itch
E B
ID =
80-
00-0
0-0c
-26-
79-2
2-22
Swit
ch A
has
the
low
est
BID
, so
it is
ele
cted
the
roo
t. E
ach
non-
root
sw
itch
mus
t no
w
elec
t a
root
por
t.
Ro
ot
Po
rt E
lecti
on
•Sw
itch
B—
Use
s th
e co
nnec
ted
link
to A
, pat
h co
st o
f 19
(lin
k sp
eed
of 1
00 M
bps)
.•
Switc
h C
—T
he c
onne
cted
link
has
a p
ath
cost
of 1
00 (l
ink
spee
d of
10
Mbp
s), t
he
link
thro
ugh
B h
as a
pat
h co
st o
f 38
(tw
o 10
0 M
bps
links
), an
d so
that
por
t is
chos
en.
•Sw
itch
D—
The
link
thr
ough
B h
as a
pat
h co
st o
f 11
9, t
he p
ath
cost
thr
ough
C t
o A
is 1
19, t
he p
ath
thro
ugh
C t
hen
B is
57,
so
that
por
t is
cho
sen.
•Sw
itch
E—
The
low
est
path
cos
t is
the
sam
e fo
r bo
th p
orts
(76
—th
roug
h D
to
C
to B
to
A).
Nex
t, c
heck
sen
der
BID
. Sen
der
for
both
por
ts is
D, s
o th
at d
oesn
’t br
eak
the
tie.
Nex
t, c
heck
sen
der
Port
ID
. Ass
umin
g de
faul
t po
rt p
rior
ity,
the
PID
fo
r 0/
1 is
low
er t
han
the
PID
for
0/2
, so
the
port
on
the
left
is t
he r
oot
port
.
Desig
nate
d P
ort
Ele
cti
on
•T
he r
oot b
ridg
e is
the
desi
gnat
ed b
ridg
e fo
r ev
ery
segm
ent
conn
ecte
d to
it (
A–B
an
d A
–C in
our
exa
mpl
e).
•Se
gmen
t B
–D—
B h
as t
he lo
wes
t pa
th
cost
to
root
(19
ver
sus
119)
, so
it is
des
-ig
nate
d fo
r th
is s
egm
ent.
•Se
gmen
t C
–D—
C h
as t
he lo
wes
t pa
th
cost
to
the
root
(10
0 ve
rsus
119
), s
o it
is
des
igna
ted
for
this
seg
men
t.•
Segm
ent
B–C
—B
has
the
low
est
path
co
st t
o th
e ro
ot (
19 v
ersu
s 10
0), s
o it
is
desi
gnat
ed f
or t
his
segm
ent.
•B
oth
segm
ents
D–E
—D
has
the
low
est
path
cos
t to
the
roo
t (5
7 ve
rsus
76)
, so
it is
des
igna
ted
for
both
seg
men
ts.
Now
the
loop
ed t
opol
ogy
has
been
tur
ned
into
a t
ree,
wit
h A
at
the
root
. Not
ice
that
no
mor
e re
dund
ant
links
exi
st.
Bri
dg
e P
roto
co
l D
ata
Un
its
Swit
ches
exc
hang
e B
ridg
e Pr
otoc
ol D
ata
Uni
ts (
BPD
Us)
. Tw
o ty
pes
of B
PDU
s ex
ist:
co
nfigu
rati
on a
nd t
opol
ogy
chan
ge.
Lin
k S
peed
Old
Co
st
New
Co
st
10 M
bps
100
100
100
Mbp
s10
19
1 G
bps
14
10 G
bps
12
A
BC
D E
0910_BCMSNssf.fm Page 457 Tuesday, September 9, 2003 8:20 AM
458 BCMSN Quick Reference SheetsC
onfig
urat
ion
BPD
Us
are
sent
eve
ry t
wo
seco
nds
from
the
roo
t to
war
ds d
owns
trea
m
swit
ches
. The
y ar
e us
ed d
urin
g an
ele
ctio
n, m
aint
ain
conn
ecti
vity
bet
wee
n sw
itch
es,
and
send
tim
er in
form
atio
n fr
om t
he r
oot.
Topo
logy
Cha
nge
(TC
N)
BPD
Us
are
sent
tow
ards
the
roo
t w
hen
•T
here
is a
link
fai
lure
.•
A p
ort
star
ts f
orw
ardi
ng, a
nd t
here
is a
lrea
dy a
des
igna
ted
port
.•
The
sw
itch
rec
eive
s a
TC
N f
rom
a n
eigh
bor.
Whe
n a
swit
ch r
ecei
ves
a T
CN
BPD
U, i
t ac
know
ledg
es t
hat
wit
h a
confi
gura
tion
B
PDU
tha
t ha
s th
e To
polo
gy C
hang
e A
ckno
wle
dgm
ent
bit
set.
Whe
n th
e ro
ot b
ridg
e re
ceiv
es a
TC
N, i
t st
arts
sen
ding
con
figur
atio
n B
PDU
s w
ith
the
Topo
logy
Cha
nge
bit
set
for
a pe
riod
of
tim
e eq
ual t
o M
ax A
ge p
lus
Forw
ard
Del
ay.
Swit
ches
tha
t re
ceiv
e th
is c
hang
e th
eir
MA
C t
able
Agi
ng T
ime
to t
he F
orw
ard
Del
ay
tim
e, c
ausi
ng M
AC
add
ress
es to
age
out
fast
er. T
he to
polo
gy c
hang
e al
so c
ause
s a
new
el
ecti
on o
f th
e ro
ot b
ridg
e, r
oot
port
s, a
nd d
esig
nate
d po
rts.
BP
DU
Fie
lds
Som
e of
the
fiel
ds in
the
BPD
U in
clud
e th
e fo
llow
ing:
•R
oot
Bri
dge
ID•
Send
er’s
Roo
t Pa
th C
ost
•Se
nder
’s B
ridg
e ID
•Se
nder
’s P
ort
ID•
Mes
sage
Age
•H
ello
tim
e—2
sec
by d
efau
lt•
Forw
ard
Del
ay—
15 s
ec b
y de
faul
t•
Max
Age
—20
sec
by
defa
ult
Sp
an
nin
g T
ree
Po
rt S
tate
sW
hen
a po
rt is
firs
t ac
tiva
ted,
it t
rans
itio
ns t
hrou
gh t
he f
ollo
win
g st
ages
:
Desig
nin
g f
or
Sp
an
nin
g T
ree
To o
ptim
ize
data
flow
in t
he n
etw
ork,
des
ign
and
confi
gure
sw
itch
es f
or t
he f
ollo
win
g ST
P ro
les:
•Pr
imar
y an
d se
cond
ary
root
bri
dges
(se
t pr
iori
ty v
alue
s)•
Des
igna
ted
and
root
por
ts (
set
port
pri
orit
ies/
path
cos
t)•
Ena
ble
STP
enha
ncem
ents
suc
h as
Roo
t G
uard
Sp
an
nin
g T
ree a
nd
PV
ST
With
PV
ST (p
er-V
LA
N s
pann
ing
tree
), a
diff
eren
t ins
tanc
e of
ST
P ex
ists
for
each
VL
AN
. To
der
ive
the
VL
AN
BID
, the
sw
itch
pick
s a
diff
eren
t MA
C a
ddre
ss fr
om it
s ba
se p
ool f
or
each
VL
AN
. Eac
h V
LA
N h
as it
s ow
n ro
ot b
ridg
e, r
oot p
ort,
etc.
You
can
con
figur
e th
ese
so th
at d
ata
flow
is o
ptim
ized
, and
traf
fic lo
ad is
bal
ance
d am
ong
the
switc
hes.
Span
ning
tre
e is
ena
bled
by
defa
ult
on e
very
VL
AN
.
Co
nfi
gu
rin
g S
pan
nin
g T
ree
To c
hang
e th
e ST
P pr
iori
ty v
alue
, typ
eSwitch(config)# spanning-tree vlan vlan no. priority value
To c
onfig
ure
a sw
itch
as
root
wit
hout
man
ually
cha
ngin
g pr
iori
ty v
alue
s, t
ype
Switch(config)# spanning-tree vlan vlan no. root {primary
| secondary}
To c
hang
e th
e ST
P po
rt c
ost
for
an a
cces
s po
rt, t
ype
Switch(config-if)# spanning-tree cost value
To c
hang
e th
e ST
P po
rt c
ost
for
a V
LA
N o
n a
trun
k po
rt, t
ype
Switch(config-if)# spanning-tree vlan vlan no. cost value
To d
ispl
ay t
he S
TP
info
rmat
ion
for
a pa
rtic
ular
VL
AN
, typ
eSwitch# show spanning-tree vlan vlan no.
Po
rt S
tate
Tim
er
Acti
on
s
Blo
ckin
gM
ax A
ge (
20 s
ec)
Dis
card
s fr
ames
, doe
s no
t le
arn
MA
C
addr
esse
s, d
oes
rece
ive
BPD
Us
Lis
teni
ngFo
rwar
d D
elay
(15
sec
)D
isca
rds
fram
es, d
oes
not
lear
n M
AC
ad
dres
ses,
rec
eive
s B
PDU
s to
det
erm
ine
its
role
in t
he n
etw
ork
Po
rt S
tate
Tim
er
Acti
on
s
Lea
rnin
gFo
rwar
d D
elay
(15
sec
)D
isca
rds
fram
es, d
oes
lear
n M
AC
ad
dres
ses,
doe
s re
ceiv
e an
d tr
ansm
it
BPD
Us
Forw
ardi
ngA
ccep
ts f
ram
es, l
earn
s M
AC
add
ress
es,
rece
ives
and
tra
nsm
its
BPD
Us
0910_BCMSNssf.fm Page 458 Tuesday, September 9, 2003 8:20 AM
Spanning Tree Enhancements 459
To d
ispl
ay t
he S
TP
info
rmat
ion
for
an in
terf
ace,
typ
eSwitch # show spanning-tree interface interface no. [detail]
To v
erif
y ST
P ti
mer
s, t
ype
####sssshhhhoooowwww ssssppppaaaannnnnnnniiiinnnngggg----ttttrrrreeeeeeee bbbbrrrriiiiddddggggeeee bbbbrrrriiiieeeeffff
Sp
an
nin
g T
ree E
nh
an
cem
en
tsC
isco
has
som
e pr
opri
etar
y en
hanc
emen
ts to
spa
nnin
g tr
ee th
at h
elp
spee
d up
net
wor
k co
nver
genc
e. T
hey
incl
ude
the
follo
win
g:•
Port
Fas
t•
Upl
ink
Fast
•B
ackb
one
Fast
Po
rt F
ast
Port
Fas
t is
for
acc
ess
(use
r) p
orts
onl
y. I
t ca
uses
the
por
t to
byp
ass
the
STP
liste
ning
an
d le
arni
ng s
tate
s, a
nd t
rans
itio
n di
rect
ly t
o fo
rwar
ding
. If
a B
PDU
is r
ecei
ved,
Por
t Fa
st is
aba
ndon
ed, t
he p
ort
plac
ed in
blo
ckin
g, a
nd t
he s
wit
ch r
uns
thro
ugh
the
enti
re
Span
ning
Tre
e pr
oced
ure.
(config-if)# spanning-tree portfast
Up
lin
k F
ast
Upl
ink
Fast
is f
or s
peed
ing
conv
erge
nce
whe
n a
dire
ct li
nk t
o an
ups
trea
m s
wit
ch f
ails
. T
he s
wit
ch id
enti
fies
back
up p
orts
for
the
roo
t po
rt (
thes
e ar
e ca
lled
an u
plin
k gr
oup)
. If
the
root
por
t fai
ls, o
ne o
f the
por
ts in
the
uplin
k gr
oup
is u
nblo
cked
and
tran
sitio
ns
imm
edia
tely
to
forw
ardi
ng—
bypa
ssin
g th
e lis
teni
ng a
nd le
arni
ng s
tage
s. I
t sh
ould
be
used
in w
irin
g cl
oset
sw
itch
es w
ith
at le
ast
one
bloc
ked
port
:(config)# spanning-tree uplinkfast
Backb
on
e F
ast
Bac
kbon
e Fa
st is
use
d fo
r sp
eedi
ng c
onve
rgen
ce w
hen
a lin
k fa
ils t
hat
is n
ot d
irec
tly
conn
ecte
d to
the
sw
itch
. It
help
s th
e sw
itch
det
ect
indi
rect
fai
lure
s. I
f a
swit
ch r
unni
ng
Bac
kbon
e Fa
st r
ecei
ves
an in
feri
or B
PDU
from
its
desi
gnat
ed b
ridg
e, it
kno
ws
a lin
k on
th
e pa
th t
o th
e ro
ot h
as f
aile
d. (
An
infe
rior
BPD
U is
one
tha
t lis
ts t
he s
ame
swit
ch f
or
root
bri
dge
and
desi
gnat
ed b
ridg
e.)
The
sw
itch
the
n tr
ies
to fi
nd a
n al
tern
ate
path
to
the
root
by
send
ing
a R
oot
Lin
k Q
uery
(R
LQ
) pr
otoc
ol d
ata
unit
(PD
U)
out
all a
lter
nate
por
ts. T
he r
oot
then
res
pond
s
with
a R
LQ
res
pons
e, a
nd th
e po
rt r
ecei
ving
this
res
pons
e ca
n tr
ansi
tion
to fo
rwar
ding
. A
lter
nate
por
ts a
re d
eter
min
ed in
thi
s w
ay:
•If
the
infe
rior
BPD
U w
as r
ecei
ved
on a
blo
cked
por
t, t
he r
oot
port
and
any
oth
er
bloc
ked
port
s ar
e co
nsid
ered
alt
erna
tes.
•If
the
infe
rior
BPD
U w
as r
ecei
ved
on t
he r
oot
port
, all
bloc
ked
port
s ar
e co
nsid
-er
ed a
lter
nate
s.•
If th
e in
feri
or B
PDU
was
rec
eive
d on
the
root
por
t and
ther
e ar
e no
blo
cked
por
ts, t
he
switc
h as
sum
es it
has
lost
con
nect
ivity
with
the
root
and
adv
ertis
es it
self
as r
oot.
Con
figur
e th
is c
omm
and
on a
ll sw
itch
es in
the
net
wor
k:(config)#spanning-tree backbonefast
Rap
id S
pan
nin
g T
ree P
roto
co
l R
apid
Spa
nnin
g Tr
ee P
roto
col (
RST
P)—
802.
1w—
is a
sta
ndar
ds-b
ased
, non
-pro
prie
tary
w
ay o
f sp
eedi
ng S
TP
conv
erge
nce.
Sw
itch
por
ts e
xcha
nge
an e
xplic
it h
ands
hake
whe
n th
ey tr
ansi
tion
to fo
rwar
ding
. RST
P de
scri
bes
diff
eren
t por
t sta
tes
than
reg
ular
ST
P, a
s sh
own
in t
he f
ollo
win
g ta
ble.
RS
TP
Po
rt R
ole
sR
STP
also
defi
nes
diff
eren
t sp
anni
ng-t
ree
role
s fo
r po
rts:
•R
oot
port
—T
he b
est
path
to
the
root
(sa
me
as S
TP)
•D
esig
nate
d po
rt—
Sam
e ro
le a
s w
ith
STP
•A
lter
nate
por
t—A
bac
kup
to t
he r
oot
port
•B
acku
p po
rt—
A b
acku
p to
the
des
igna
ted
port
•D
isab
led
port
—O
ne n
ot u
sed
in t
he s
pann
ing
tree
•E
dge
port
—O
ne c
onne
cted
onl
y to
an
end
user
ST
P P
ort
Sta
teE
qu
iva
len
t R
ST
P P
ort
Sta
te
Dis
able
dD
isca
rdin
g
Blo
ckin
gD
isca
rdin
g
Lis
teni
ngD
isca
rdin
g
Lea
rnin
gL
earn
ing
Forw
ardi
ngFo
rwar
ding
0910_BCMSNssf.fm Page 459 Tuesday, September 9, 2003 8:20 AM
460 BCMSN Quick Reference SheetsB
PD
U D
iffe
ren
ces in
RS
TP
In r
egul
ar S
TP,
BPD
Us
are
orig
inat
ed b
y th
e ro
ot a
nd r
elay
ed b
y ea
ch s
wit
ch. I
n R
STP,
ea
ch s
wit
ch o
rigi
nate
s B
PDU
s, w
heth
er o
r no
t it
rec
eive
s a
BPD
U o
n it
s ro
ot p
ort.
All
8 bi
ts o
f th
e B
PDU
typ
e fie
ld a
re u
sed
by R
STP.
The
TC
and
TC
Ack
bit
s ar
e st
ill u
sed;
th
e ot
her
6 bi
ts s
peci
fy t
he p
ort’s
rol
e an
d it
s R
STP
stat
e an
d ar
e us
ed in
the
por
t ha
nd-
shak
e. T
he R
STP
BPD
U is
set
to
Type
2, V
ersi
on 2
. PV
ST is
don
e by
Rap
id p
er-V
LA
N
span
ning
tre
e pl
us (
PVST
+) o
n C
atal
yst
swit
ches
.
RS
TP
Fast
Co
nverg
en
ce
•R
STP
uses
a m
echa
nism
sim
ilar
to B
ackb
one
Fast
—W
hen
an in
feri
or B
PDU
is
rece
ived
, the
sw
itch
acc
epts
it. I
f th
e sw
itch
has
ano
ther
pat
h th
e ro
ot, i
t us
es t
hat
and
info
rms
its
dow
nstr
eam
sw
itch
of
the
alte
rnat
e pa
th.
•E
dge
port
s w
ork
the
sam
e as
Por
t Fa
st p
orts
—T
hey
auto
mat
ical
ly t
rans
itio
n di
rect
ly t
o fo
rwar
ding
.•
Lin
k ty
pe—
If y
ou c
onne
ct t
wo
swit
ches
thr
ough
a p
oint
-to-
poin
t lin
k an
d th
e lo
cal p
ort
beco
mes
a d
esig
nate
d po
rt, i
t ex
chan
ges
a ha
ndsh
ake
wit
h th
e ot
her
port
to
quic
kly
tran
siti
on t
o fo
rwar
ding
. Ful
l-du
plex
link
s ar
e as
sum
ed t
o be
po
int-
to-p
oint
; hal
f-du
plex
link
s ar
e as
sum
ed t
o be
sha
red.
•A
lso,
bac
kup
and
alte
rnat
e po
rts
can
tran
siti
on t
o fo
rwar
ding
whe
n no
BPD
Us
are
rece
ived
fro
m a
nei
ghbo
r sw
itch
(si
mila
r to
Upl
ink
Fast
).If
an
RST
P sw
itch
det
ects
a t
opol
ogy
chan
ge, i
t se
ts a
TC
tim
er t
o tw
ice
the
hello
tim
e an
d se
ts t
he T
C b
it o
n al
l BPD
Us
sent
out
its
desi
gnat
ed a
nd r
oot
port
s un
til t
he t
imer
ex
pire
s. I
t al
so c
lear
s th
e M
AC
add
ress
es le
arne
d on
the
se p
orts
.If
an
RST
P sw
itch
rec
eive
s a
TC
BPD
U, i
t cl
ears
the
MA
C a
ddre
sses
on
that
por
t an
d se
ts t
he T
C b
it o
n al
l BPD
Us
sent
out
its
desi
gnat
ed a
nd r
oot
port
s un
til t
he T
C t
imer
ex
pire
s.
Mu
ltip
le S
pan
nin
g T
ree (
MS
T)
With
MST
, you
can
gro
up V
LA
Ns
and
run
just
one
inst
ance
of s
pann
ing
tree
for
a gr
oup
of V
LA
Ns.
Thi
s cu
ts d
own
on t
he n
umbe
r of
BPD
Us
in y
our
netw
ork.
Sw
itch
es in
the
sa
me
MST
Reg
ion
shar
e th
e sa
me
confi
gura
tion
and
VL
AN
map
ping
s. C
onfig
ure
MST
w
ith
thes
e co
mm
ands
:(config)# spanning-tree mode mst
(config)# spanning-tree mst configuration
(config-mst)# name region_name
(config-mst)# revision number
(config-mst)# instance number vlan vlan r
ange
(config-mst)# end
To b
e co
mpa
tibl
e w
ith
802.
1Q t
runk
ing,
whi
ch h
as o
ne C
omm
on S
pann
ing
Tree
(C
ST)
for
all V
LA
Ns,
MST
run
s on
e in
stan
ce o
f an
Int
erna
l Spa
nnin
g Tr
ee (
IST
). T
he
IST
app
ears
as
one
brid
ge t
o a
CST
are
a an
d is
MST
inst
ance
num
ber
0. T
he o
rigi
nal
MST
spa
nnin
g tr
ees
(cal
led
M-T
rees
) ar
e ac
tive
onl
y w
ithi
n th
e re
gion
—th
ey c
ombi
ne
at t
he e
dge
of t
he C
ST a
rea
to f
orm
one
.
Eth
erC
han
nel
Ethe
rCha
nnel
is a
way
of c
ombi
ning
sev
eral
phy
sica
l lin
ks b
etw
een
switc
hes
into
one
logi
cal
conn
ectio
n. N
orm
ally
, spa
nnin
g tr
ee w
ould
blo
ck r
edun
dant
link
s. E
ther
Cha
nnel
get
s ar
ound
that
and
allo
ws
load
bal
anci
ng a
cros
s th
ose
links
. Loa
d ba
lanc
ing
is d
one
base
d on
su
ch th
ings
as
sour
ce o
r de
stin
atio
n M
AC
add
ress
or
IP a
ddre
ss. A
t glo
bal c
onfig
mod
e, ty
peport-channel load-balance type
A lo
gica
l int
erfa
ce—
the
Port
Cha
nnel
inte
rfac
e—is
cre
ated
. Con
figur
atio
n ca
n be
ap
plie
d bo
th t
o th
e lo
gica
l and
phy
sica
l int
erfa
ces.
Her
e ar
e so
me
guid
elin
es f
or E
ther
Cha
nnel
:•
Inte
rfac
es in
the
cha
nnel
do
not
have
to
be p
hysi
cally
nex
t to
eac
h ot
her
or o
n th
e sa
me
mod
ule.
•A
ll po
rts
mus
t be
the
sam
e sp
eed
and
dupl
ex.
•A
ll po
rts
in t
he E
ther
Cha
nnel
bun
dle
shou
ld b
e en
able
d.•
Non
e of
the
bun
dle
port
s ca
n be
a S
wit
ch P
ort
Ana
lyze
r (S
PAN
) po
rt.
•A
ssig
n an
IP
addr
ess
to t
he lo
gica
l Por
t C
hann
el in
terf
ace,
not
the
phy
sica
l one
s.•
Put
all b
undl
e po
rts
in t
he s
ame
VL
AN
, or
mak
e th
em a
ll tr
unks
. If
they
are
tr
unks
, the
y m
ust
all c
arry
the
sam
e V
LA
Ns
and
use
the
sam
e tr
unki
ng m
ode.
•C
onfig
urat
ion
you
appl
y to
the
Port
Cha
nnel
inte
rfac
e af
fect
s th
e en
tire
Ethe
rCha
nnel
. C
onfig
urat
ion
you
appl
y to
a p
hysi
cal i
nter
face
aff
ects
onl
y th
at in
terf
ace.
Co
nfi
gu
rin
g a
n E
therC
ha
nn
el
Bas
ical
ly, f
or a
Lay
er 3
Eth
erC
hann
el, c
onfig
ure
the
logi
cal i
nter
face
and
the
n pu
t th
e ph
ysic
al in
terf
aces
into
the
cha
nnel
gro
up:
interface port-channel number
nnnnoooo sssswwwwiiiittttcccchhhhppppoooorrrrtttt
ip address address mask
The
n, a
t ea
ch p
ort
that
is p
art
of t
he E
ther
Cha
nnel
:interface { number
| range interface – interface}
channel-group number mode {auto
| desirable
| on}
0910_BCMSNssf.fm Page 460 Tuesday, September 9, 2003 8:20 AM
Spanning Tree Enhancements 461
Putt
ing
the
IP a
ddre
ss o
n th
e Po
rt C
hann
el in
terf
ace
crea
tes
a L
ayer
3 E
ther
Cha
nnel
. Si
mpl
y pu
ttin
g in
terf
aces
into
a c
hann
el g
roup
cre
ates
a L
ayer
2 E
ther
Cha
nnel
, and
the
logi
cal i
nter
face
is a
utom
atic
ally
cre
ated
.T
he C
isco
pro
prie
tary
Por
t A
ggre
gati
on P
roto
col (
PAgP
) dy
nam
ical
ly n
egot
iate
s th
e fo
rmat
ion
of a
cha
nnel
. Thr
ee P
AgP
mod
es e
xist
:•
On—
The
por
t ch
anne
ls w
itho
ut u
sing
PA
gP n
egot
iati
on. T
he p
ort
on t
he o
ther
si
de m
ust
also
be
set
to O
n.•
Aut
o—R
espo
nds
to P
AgP
mes
sage
s bu
t doe
s no
t ini
tiat
e th
em. P
ort c
hann
els
if th
e po
rt o
n th
e ot
her
end
is s
et t
o D
esir
able
. Thi
s is
the
def
ault
mod
e.•
Des
irab
le—
Port
act
ivel
y ne
goti
ates
cha
nnel
ing
stat
us w
ith
the
inte
rfac
e on
the
ot
her
end
of t
he li
nk. P
ort
chan
nels
if o
ther
sid
e is
Aut
o or
Des
irab
le.
Als
o, a
non
-pro
prie
tary
pro
toco
l cal
led
Lin
k A
ggre
gati
on C
ontr
ol P
roto
col (
LA
CP)
, IE
EE
802
.3ad
, doe
s th
e sa
me
thin
g. L
AC
P ha
s tw
o m
odes
:•
Act
ive—
Port
act
ivel
y ne
goti
ates
cha
nnel
ing
wit
h th
e po
rt o
n th
e ot
her
end
of t
he
link.
Cha
nnel
for
ms
if o
ther
sid
e is
pas
sive
or
acti
ve.
•Pa
ssiv
e—R
espo
nds
to L
AC
P m
essa
ges
but
does
not
init
iate
the
m. C
hann
el f
orm
s if
oth
er e
nd is
set
to
acti
ve.
If y
ou w
ant
to u
se L
AC
P, s
peci
fy it
und
er t
he in
terf
ace
and
put
the
inte
rfac
e in
eit
her
acti
ve o
r pa
ssiv
e m
ode.
cccchhhhaaaannnnnnnneeeellll----pppprrrroooottttooooccccoooollll llllaaaaccccpppp
Veri
fyin
g a
n E
therC
han
nel
Her
e ar
e so
me
typi
cal c
omm
ands
for
ver
ifyi
ng a
n E
ther
Cha
nnel
:•
show
run
ning
-con
fig in
terf
ace
num
ber
•sh
ow in
terf
aces
num
ber
ethe
rcha
nnel
•sh
ow e
ther
chan
nel n
umbe
r po
rt-c
hann
el•
show
eth
erch
anne
l sum
mar
y
Ad
dit
ion
al S
pan
nin
g T
ree F
eatu
res
Som
e ad
diti
onal
fea
ture
s av
aila
ble
to h
elp
you
tune
spa
nnin
g tr
ee in
clud
e•
BPD
U G
uard
•B
PDU
Filt
erin
g•
Roo
t G
uard
•U
nidi
rect
iona
l Lin
k D
etec
tion
(U
DL
D)
•L
oop
Gua
rd
BP
DU
Gu
ard
BPD
U G
uard
pre
vent
s lo
ops
if a
noth
er s
wit
ch is
att
ache
d to
a P
ort
Fast
por
t. W
hen
BPD
U G
uard
is e
nabl
ed o
n an
inte
rfac
e, it
is p
ut in
to a
n er
ror-
disa
bled
sta
te (
basi
cally
, sh
ut d
own)
if a
BPD
U is
rec
eive
d on
the
inte
rfac
e. I
t ca
n be
ena
bled
at
eith
er g
loba
l co
nfig
mod
e—in
whi
ch c
ase
it a
ffec
ts a
ll Po
rt F
ast
inte
rfac
es—
or a
t in
terf
ace
mod
e.
Port
Fas
t do
es n
ot h
ave
to b
e en
able
d fo
r it
to
be c
onfig
ured
at
a sp
ecifi
c in
terf
ace.
(config)# spanning-tree portfast bpduguard default
(config-if)# spanning-tree bpduguard enable
BP
DU
Filte
rin
gB
PDU
filt
erin
g is
ano
ther
way
of
prev
enti
ng lo
ops
in t
he n
etw
ork.
It
also
can
be
enab
led
eith
er g
loba
lly o
r at
the
inte
rfac
e an
d fu
ncti
ons
diff
eren
tly
at e
ach.
In
glob
al
confi
g, if
a P
ort
Fast
inte
rfac
e re
ceiv
es a
ny B
PDU
s, it
is t
aken
out
of
Port
Fas
t st
atus
. A
t in
terf
ace
confi
g m
ode,
it p
reve
nts
the
port
fro
m s
endi
ng o
r re
ceiv
ing
BPD
Us.
The
co
mm
ands
are
(config)# spanning-tree portfast bpdufilter default
(config-if)# spanning-tree bpdufilter enable
Ro
ot
Gu
ard
Roo
t G
uard
is m
eant
to
prev
ent
the
wro
ng s
wit
ch f
rom
bec
omin
g th
e sp
anni
ng-t
ree
root
. It i
s en
able
d on
por
ts o
ther
than
the
root
por
t, o
n sw
itch
es o
ther
than
the
root
. If
a R
oot
Gua
rd p
ort
rece
ives
a B
PDU
tha
t w
ould
cau
se it
to
beco
me
a ro
ot p
ort,
the
po
rt is
put
into
“ro
ot-i
ncon
sist
ent”
sta
te a
nd d
oes
not
pass
tra
ffic
thro
ugh
it. I
f th
e po
rt s
tops
rec
eivi
ng t
hese
BPD
Us,
it a
utom
atic
ally
re-
enab
les
itse
lf.
(config-if)# spanning-tree guard root
Un
idir
ecti
on
al Lin
k D
ete
cti
on
(U
DLD
)A
sw
itch
not
ices
whe
n a
phys
ical
con
nect
ion
is b
roke
n, b
y th
e ab
senc
e of
Lay
er 1
ele
c-tr
ical
kee
paliv
es (
Eth
erne
t ca
lls t
his
a lin
k be
at).
But
som
etim
es, a
cab
le is
inta
ct e
noug
h to
mai
ntai
n ke
epal
ives
, but
not
to
pass
dat
a in
bot
h di
rect
ions
. Thi
s is
a u
nidi
rect
iona
l lin
k. U
DL
D d
etec
ts a
uni
dire
ctio
nal l
ink
by s
endi
ng p
erio
dic
hello
s ou
t the
inte
rfac
e. It
al
so u
ses
prob
es, w
hich
mus
t be
ackn
owle
dged
by
the
devi
ce o
n th
e ot
her
end
of th
e lin
k.
UD
LD
ope
rate
s at
Lay
er 2
. The
por
t is
shut
dow
n if
a un
idir
ectio
nal l
ink
is fo
und.
•To
ena
ble
UD
LD
on
all fi
ber-
opti
c in
terf
aces
, use
thi
s co
mm
and:
(config)# udld enable
0910_BCMSNssf.fm Page 461 Tuesday, September 9, 2003 8:20 AM
462 BCMSN Quick Reference SheetsA
ltho
ugh
this
com
man
d is
giv
en a
t gl
obal
con
fig m
ode,
it a
pplie
s on
ly t
o fib
er
port
s.
•To
ena
ble
UD
LD
on
non-
fiber
por
ts, g
ive
the
sam
e co
mm
and
at in
terf
ace
confi
g m
ode.
•To
dis
able
UD
LD
on
a sp
ecifi
c fib
er p
ort,
use
thi
s co
mm
and:
(config-if)# udld disable
•To
dis
able
UD
LD
on
a sp
ecifi
c no
n-fib
er p
ort,
use
thi
s co
mm
and:
(config-if)#no udld enable
•To
re-
enab
le a
ll in
terf
aces
shu
t by
UD
LD
:#udld reset
•To
ver
ify
UD
LD
sta
tus:
#show udld interface
Lo
op
Gu
ard
Loo
p G
uard
pre
vent
s lo
ops
that
mig
ht d
evel
op if
a p
ort
that
sho
uld
be b
lock
ing
inad
-ve
rten
tly tr
ansi
tions
to th
e fo
rwar
ding
sta
te. T
his
can
happ
en if
the
port
sto
ps r
ecei
ving
B
PDU
s (p
erha
ps b
ecau
se o
f a
unid
irec
tion
al li
nk o
r a
soft
war
e/co
nfigu
rati
on p
robl
em
in it
s ne
ighb
or s
wit
ch).
Whe
n on
e of
the
por
ts in
a p
hysi
cally
red
unda
nt t
opol
ogy
stop
s re
ceiv
ing
BPD
Us,
the
STP
conc
eive
s th
e to
polo
gy a
s lo
op-f
ree.
Eve
ntua
lly, t
he b
lock
ing
port
bec
omes
des
igna
ted,
and
mov
es t
o fo
rwar
ding
sta
te, t
hus
crea
ting
a lo
op. W
ith
Loo
p G
uard
ena
bled
, an
addi
tion
al c
heck
is m
ade.
If n
o B
PDU
s ar
e re
ceiv
ed o
n a
bloc
ked
port
for
a s
peci
fic le
ngth
of
tim
e, L
oop
Gua
rd
puts
tha
t po
rt in
to “
loop
inco
nsis
tent
” bl
ocki
ng s
tate
, rat
her
than
tra
nsit
ioni
ng t
o fo
rwar
ding
sta
te. L
oop
Gua
rd s
houl
d be
ena
bled
on
all s
wit
ch p
orts
tha
t ha
ve a
cha
nce
of b
ecom
ing
root
or
desi
gnat
ed p
orts
. It
is m
ost
effe
ctiv
e w
hen
enab
led
in t
he e
ntir
e sw
itch
ed n
etw
ork,
in c
onju
ncti
on w
ith
UD
LD
.To
ena
ble
Loo
p G
uard
for
all
poin
t-to
-poi
nt li
nks
on t
he s
wit
ch, u
se t
he f
ollo
win
g co
mm
and:
(config)# spanning-tree loopguard default
To e
nabl
e L
oop
Gua
rd o
n a
spec
ific
inte
rfac
e, t
ype
(config-if)# spanning-tree guard loop
Loo
p G
uard
aut
omat
ical
ly r
e-en
able
s th
e po
rt if
it s
tart
s re
ceiv
ing
BPD
Us
once
aga
in.
Tro
ub
lesh
oo
tin
g S
TP
Som
e co
mm
on th
ings
to lo
ok fo
r w
hen
trou
bles
hoot
ing
Span
ning
Tre
e Pr
otoc
ol in
clud
e•
Dup
lex
mis
mat
ch—
Whe
n on
e si
de o
f th
e lin
k is
hal
f du
plex
and
the
oth
er is
ful
l du
plex
. Cau
ses
late
col
lisio
ns a
nd F
CS
erro
rs.
•U
nidi
rect
iona
l lin
k fa
ilure
—W
hen
the
link
is u
p bu
t dat
a on
ly fl
ows
in o
ne d
irec
tion.
C
an c
ause
loop
s.•
Fram
e co
rrup
tion
—Ph
ysic
al e
rror
s on
the
line
cau
se B
PDU
s to
be
lost
, and
the
po
rt in
corr
ectl
y be
gins
forw
ardi
ng. C
ause
d by
dup
lex
mis
mat
ch, b
ad c
able
, or
too
long
of
cabl
e.•
Res
ourc
e er
rors
—ST
P is
impl
emen
ted
in s
oftw
are,
so
a sw
itch
wit
h an
ove
rloa
ded
CPU
or
mem
ory
can
negl
ect
som
e ST
P du
ties
.•
Port
Fas
t co
nfigu
rati
on e
rror
s—C
onne
ctin
g a
swit
ch t
o tw
o po
rts
that
hav
e Po
rt
Fast
ena
bled
. Can
cau
se a
loop
.•
STP
tuni
ng e
rror
s—M
ax A
ge o
r Fo
rwar
d D
elay
set
too
sho
rt c
an c
ause
a lo
op.
Net
wor
k di
amet
er s
et t
oo lo
w c
ause
s B
PDU
s to
be
disc
arde
d an
d af
fect
ST
P co
nver
genc
e.
Iden
tify
ing
a B
rid
gin
g L
oo
pSu
spec
t a
loop
if y
ou s
ee t
he f
ollo
win
g:•
You
cap
ture
the
tra
ffic
on t
he o
verl
oade
d lin
k an
d se
e th
e sa
me
fram
es m
ulti
ple
tim
es. T
his
sign
ifies
a lo
op.
•A
ll us
ers
in o
ne b
ridg
ing
dom
ain
have
con
nect
ivit
y pr
oble
ms
at t
he s
ame
tim
e.•
An
abno
rmal
ly h
igh
acti
vity
exi
sts
whe
n ch
ecki
ng p
ort
utili
zati
on.
To r
emed
y a
loop
qui
ckly
, shu
t re
dund
ant
port
s an
d th
en e
nabl
e th
em o
ne a
t a
tim
e.
Som
e sw
itche
s al
low
deb
uggi
ng o
f ST
P (n
ot 3
550/
2950
) to
help
in d
iagn
osin
g pr
oble
ms.
0910_BCMSNssf.fm Page 462 Tuesday, September 9, 2003 8:20 AM
Multilayer Switching 463
Wh
at
to U
se W
here
Con
fuse
d by
all
the
acro
nym
s an
d ST
P fe
atur
es?
The
follo
win
g di
agra
m s
how
s th
e ST
P fe
atur
es y
ou m
ight
use
in y
our
netw
ork,
and
whe
re y
ou m
ight
use
the
m.
Mu
ltilayer
Sw
itch
ing
Un
ders
tan
din
g t
he S
wit
ch
ing
Pro
cess
Her
e ar
e th
e st
eps
invo
lved
in L
ayer
2 f
orw
ardi
ng:
Inpu
t1.
Rec
eive
fra
me
2.V
erif
y fr
ame
inte
grit
y3.
App
ly in
boun
d V
LA
N a
cces
s co
ntro
l lis
t (A
CL
)4.
Loo
kup
dest
inat
ion
MA
CO
utpu
t1.
App
ly o
utbo
und
VL
AN
AC
L2.
App
ly o
utbo
und
QoS
AC
L3.
Sele
ct o
utpu
t po
rt4.
Que
ue o
n po
rt5.
Rew
rite
6.Fo
rwar
d
Her
e ar
e th
e st
eps
invo
lved
in L
ayer
3 f
orw
ardi
ng:
Inpu
t1.
Rec
eive
fra
me
2.V
erif
y fr
ame
inte
grit
y3.
App
ly in
boun
d V
LA
N A
CL
4.L
ooku
p de
stin
atio
n M
AC
Rou
ting
1.In
put
AC
L2.
Swit
ch if
ent
ry c
ache
d3.
Iden
tify
exi
t in
terf
ace
and
next
-hop
add
ress
usi
ng r
outi
ng t
able
4.O
utpu
t A
CL
Out
put
1.A
pply
out
boun
d V
LA
N A
CL
2.A
pply
out
boun
d Q
oS A
CL
3.Se
lect
out
put
port
4.Q
ueue
on
port
5.R
ewri
te s
ourc
e an
d de
stin
atio
n M
AC
, IP
chec
ksum
, and
fra
me
chec
k se
quen
ce
(FC
S); d
ecre
men
t T
ime
to L
ive
(TT
L)
6.Fo
rwar
d
Un
ders
tan
din
g t
he S
wit
ch
ing
Tab
leC
onte
nt A
ddre
ssab
le M
emor
y (C
AM
)•
Use
d fo
r C
atal
yst
4000
Lay
er 2
for
war
ding
tab
les
•U
sed
for
Cat
alys
t 65
00 L
ayer
2 a
nd N
etFl
ow f
orw
ardi
ng t
able
s•
Bin
ary
valu
es (
0 or
1)
•M
atch
mus
t be
exa
ctT
erna
ry C
onte
nt A
ddre
ssab
le M
emor
y (T
CA
M)
•U
sed
for
Cat
alys
t 35
50, 4
000,
and
650
0 L
ayer
3 s
wit
chin
g•
Tern
ary
(3)
valu
es (
0, 1
, or
wild
card
)•
Ent
ries
are
in V
MR
for
m:
—V
alue
—Pa
tter
n to
be
mat
ched
—M
ask—
Mas
king
bit
s as
soci
ated
wit
h pa
tter
n
—R
esul
t—C
onse
quen
ces
of a
mat
ch (
perm
it/d
eny,
or
mor
e co
mpl
ex in
form
atio
n
Ro
ot
Bri
dg
e
UD
LD
UD
LD
UD
LD
UD
LD
,LoopG
uard
RootG
uard
,U
DLD
RootG
uard
,U
DLD
UD
LD
UD
LD
,LoopG
uard
Back
boneF
ast
,B
PD
U F
ilter
Port
Fast
,B
PD
U G
uard
Forw
ard
ing
Blo
ckin
g
Uplin
kFast
0910_BCMSNssf.fm Page 463 Tuesday, September 9, 2003 8:20 AM
464 BCMSN Quick Reference SheetsU
nd
ers
tan
din
g S
wit
ch
Fo
rwa
rdin
g A
rch
ite
ctu
res
Cen
tral
ized
For
war
ding
•D
ecis
ion
mad
e by
sin
gle
tabl
e•
Use
d by
400
0 an
d 65
00D
istr
ibut
ed F
orw
ardi
ng•
Dec
isio
n m
ade
at p
ort
or m
odul
e•
Use
d by
355
0 an
d 65
00 w
ith
dist
ribu
ted
forw
ardi
ng c
ard
Net
Flow
Sw
itch
ing
•D
ecis
ion
mad
e co
oper
ativ
ely
by r
oute
pro
cess
or a
nd M
ulti
laye
r Sw
itch
ing
(ML
S)•
Firs
t pa
cket
sw
itch
ed in
sof
twar
e; r
esul
t ca
ched
•Su
bseq
uent
pac
kets
sw
itch
ed in
har
dwar
eC
isco
Exp
ress
For
war
ding
(C
EF)
•To
polo
gy b
ased
sw
itch
ing
(via
For
war
ding
Inf
orm
atio
n B
ase
[FIB
])•
Can
be
cent
raliz
ed o
r di
stri
bute
d
Cis
co
Ex
pre
ss F
orw
ard
ing
(C
EF
)C
EF
does
the
fol
low
ing:
•Se
para
tes
cont
rol p
lane
har
dwar
e fr
om d
ata
plan
e ha
rdw
are
•C
ontr
ols
plan
e ru
ns in
sof
twar
e an
d bu
ilds
Forw
ardi
ng I
nfor
mat
ion
Bas
e (F
IB)
and
adja
cenc
y ta
ble
•T
he d
ata
plan
e us
es h
ardw
are
to f
orw
ard
mos
t IP
uni
cast
tra
ffic
•H
andl
es t
raffi
c th
at m
ust
be f
orw
arde
d in
sof
twar
e (m
uch
slow
er)
incl
udin
g:—
Pack
ets
orig
inat
ing
from
dev
ice
—Pa
cket
s w
ith
IP h
eade
r op
tion
s
—Tu
nnel
ed t
raffi
c
—80
2.3
(IPX
) fr
ames
•Su
ppor
ts lo
ad s
hari
ng•
FIB
is a
n op
tim
ized
rou
ting
tab
le, s
tore
d in
TC
AM
•B
uild
s ad
jace
ncie
s fr
om A
ddre
ss R
esol
utio
n Pr
otoc
ol (
AR
P) d
ata
AR
P th
rott
ling:
•Fi
rst
pack
et t
o de
stin
atio
n fo
rwar
ded
to r
oute
pro
cess
or•
Subs
eque
nt t
raffi
c dr
oppe
d un
til M
AC
res
olve
d•
Prev
ents
ove
rwhe
lmin
g R
P w
ith
redu
ndan
t A
RP
requ
ests
•H
elps
dur
ing
deni
al-o
f-se
rvic
e at
tack
s; r
emov
ed w
hen
MA
C r
esol
ved
or in
2 s
econ
ds
Co
nfi
gu
rin
g a
nd
Tro
ub
lesh
oo
tin
g C
EF
By
defa
ult,
CE
F is
on
and
supp
orts
per
des
tina
tion
load
sha
ring
.To
dis
able
CE
F:•
4000
: no
ip c
ef.
•35
50: O
n ea
ch in
terf
ace,
use
no
ip r
oute
-cac
he c
ef.
•65
50 w
ith
Polic
y Fe
atur
e C
ard,
Dis
trib
uted
FC
, and
Mul
tila
yer
Swit
ch F
C:
Can
not
be d
isab
led.
Vie
w C
EF
info
rmat
ion:
sssshhhhoooowwww iiiinnnntttteeeerrrrffffaaaacccceeee ffffaaaasssstttteeeetttthhhheeeerrrrnnnneeeetttt 2222////2222
| bbbbeeeeggggiiiinnnn LLLL3333
Vie
w s
wit
chin
g st
atis
tics
:sssshhhhoooowwww iiiinnnntttteeeerrrrffffaaaacccceeee ffffaaaasssstttteeeetttthhhheeeerrrrnnnneeeetttt 2222////2222
| iiiinnnncccclllluuuuddddeeee sssswwwwiiiittttcccchhhheeeedddd
BG
P T
able
Add
ress
Pre
fixA
S-P
ath
Com
mun
ities
Oth
er A
ttr.
Nex
t-H
op
10.0
.0.0
/842
13
37:1
21.
2.3.
4
......
......
......
IP R
ou
tin
gTa
ble
Add
ress
Pre
fix
......
FIB
Tab
le(C
EF
Cac
he)
Nex
t-H
opO
utgo
ing
Inte
rfac
eA
ddre
ssP
roto
col
BG
P
AR
P C
ache
Adj
acen
cy P
oint
er
...
1.5.
4.1
Eth
erne
t 01.
2.3.
0O
SP
F
MA
C A
ddre
ss
...
IP A
ddre
ss
...
Laye
r 2
Hea
der
...
Ad
jace
ncy
Tab
le
IP A
ddre
ss
...
1.5.
4.1
MA
C H
ead
er
Pre
fix
/24
Pre
cede
nce
—
QoS
Gro
up
— —
1.2.
3.4
—10
.0.0
.0/8
37
BG
P T
able
Map
Pre
cede
nce
...
QoS
Gro
up
... 0c.0
0.11
.22.
33.4
41.
5.4.
1
10.0
.0.0
/81.
5.4.
13
7
Con
n.1.
5.4.
0/2
4—
Eth
erne
t 0—
0910_BCMSNssf.fm Page 464 Tuesday, September 9, 2003 8:20 AM
Multilayer Switch Reliability 465
Vie
w F
IB: s
how
ip c
efV
iew
det
aile
d C
EF
FIB
ent
ry:
sssshhhhoooowwww iiiipppp cccceeeeffff ffffaaaasssstttteeeetttthhhheeeerrrrnnnneeeetttt 2222////2222 11110000....0000....0000....1111 ddddeeeettttaaaaiiiillll
Tro
uble
shoo
t C
EF
drop
s:ddddeeeebbbbuuuugggg iiiipppp cccceeeeffff ddddrrrrooooppppssss
Tro
uble
shoo
t pa
cket
s no
t fo
rwar
ded
by C
EF:
ddddeeeebbbbuuuugggg iiiipppp cccceeeeffff rrrreeeecccceeeeiiiivvvveeee
Tro
uble
shoo
t C
EF
even
ts:
ddddeeeebbbbuuuugggg iiiipppp cccceeeeffff eeeevvvveeeennnnttttssss
Inte
r-V
LA
N R
ou
tin
g
Inte
r-V
LA
N R
ou
tin
g U
sin
g M
ult
ilayer
Sw
itch
es
Port
rol
es:
•V
LA
N p
ort—
Act
s as
Lay
er 2
sw
itch
ing
port
wit
h a
VL
AN
—St
atic
VL
AN
—U
se s
wit
chpo
rt c
omm
and
to id
enti
fy V
LA
N
—D
ynam
ic V
LA
N—
Use
VL
AN
Mem
bers
hip
Polic
y Se
rver
(V
MPS
)
•T
runk
por
t—Pa
sses
mul
tipl
e V
LA
Ns
and
diff
eren
tiat
es b
y ta
ggin
g—
Use
sw
itch
port
com
man
d to
set
par
amet
ers
—IS
L o
r 80
2.1Q
•Sw
itch
vir
tual
inte
rfac
e (S
VI)
—V
irtu
al r
oute
d po
rt in
a V
LA
N—
Use
to
rout
e or
fal
lbac
k br
idge
bet
wee
n V
LA
Ns
—D
efau
lt S
VI
for
VL
AN
1 a
utom
atic
ally
cre
ated
—A
ssoc
iate
wit
h V
LA
N u
sing
inte
rfac
e vl
an#
•R
oute
d po
rt—
Act
s as
Lay
er 3
rou
ted
port
—Pl
ace
in L
ayer
3 m
ode
wit
h no
sw
itch
port
—N
ot a
ssoc
iate
d w
ith
VL
AN
—Tu
rn o
n ro
utin
g us
ing
ip r
outi
ng
—A
ssig
n ad
dres
s an
d en
able
rou
ting
pro
toco
ls a
s ne
eded
Inte
r-V
LA
N R
ou
tin
gM
ulti
laye
r sw
itch
es d
o th
e fo
llow
ing:
•E
nabl
e IP
rou
ting
usi
ng ip
rou
ting
•C
reat
e SV
I us
ing
inte
rfac
e vl
an#
•A
ssig
n IP
add
ress
to
each
inte
rfac
eR
oute
r-on
-a-s
tick
—A
ttac
h ro
uter
to
swit
ch u
sing
tru
nk li
ne (
ISL
or
802.
1Q):
•E
asy
to im
plem
ent
•U
ses
exis
ting
equ
ipm
ent
•M
uch
mor
e la
tenc
y th
an M
LS
solu
tion
•C
onfig
ure
by c
reat
ing
subi
nter
face
—in
terf
ace
fast
ethe
rnet
1/0
.7•
Ass
ocia
te V
LA
N t
o in
terf
ace
wit
h co
mm
and
enca
psul
atio
n is
l 7 o
r en
caps
ulat
ion
dot1
q 7:
—IS
L—
No
addr
ess
on m
ain
inte
rfac
e
—80
2.1Q
—A
ddre
ss o
n m
ain
inte
rfac
e fo
r na
tive
(un
tagg
ed)
VL
AN
Mu
ltilayer
Sw
itch
Reliab
ilit
y
Eq
uip
men
t G
oals
Net
wor
k ha
rdw
are
shou
ld b
e re
liabl
e an
d fa
ult-
tole
rant
. The
net
wor
k sh
ould
be
opti
-m
ized
and
eve
ry o
ppor
tuni
ty t
o im
plem
ent
redu
ndan
cy s
crut
iniz
ed.
Opp
ortu
niti
es t
o im
plem
ent
hard
war
e re
dund
ancy
:•
Supe
rvis
or c
ard
—Se
cond
Sup
ervi
sor
prov
ides
bac
kup
wit
hout
cos
t of
new
sw
itch
.—
Supe
rvis
or c
onfig
urat
ion
and
swit
chov
er m
aint
aine
d by
Rou
te P
roce
ssor
R
edun
danc
y (R
PR)
or R
oute
Pro
cess
or R
edun
danc
y Pl
us (
RPR
+).
—R
PR—
Red
unda
nt S
uper
viso
r bo
ots,
dra
ws
confi
gura
tion
, whe
n m
ain
Supe
rvi-
sor
dies
. Abo
ut 3
min
utes
fai
love
r.—
RPR
+—R
edun
dant
Sup
ervi
sor
alre
ady
boot
ed a
nd m
aint
aine
d in
syn
chro
nize
d st
ate.
Bot
h Su
perv
isor
s m
ust
use
sam
e IO
S. F
ailo
ver
in le
ss t
han
min
ute.
—FI
B t
able
bla
nk a
t sw
itch
over
.—
Ena
ble
wit
h co
mm
and
redu
ndan
cy.
—Id
enti
fy r
edun
danc
y pr
otoc
ol u
sing
mod
e rp
r-pl
us.
—V
iew
set
ting
s w
ith
show
red
unda
ncy
stat
es.
—U
plin
k po
rts
for
back
up S
uper
viso
r ar
e ac
tive
.—
Split
red
unda
nt li
nks
betw
een
Supe
rvis
ors
so th
at fa
ilure
doe
sn’t
rem
ove
both
link
s.
0910_BCMSNssf.fm Page 465 Tuesday, September 9, 2003 8:20 AM
466 BCMSN Quick Reference Sheets•
Pow
er s
uppl
y—
Som
e sw
itch
mod
els
allo
w f
or r
edun
dant
pow
er s
uppl
ies.
—Pl
ace
in b
acku
p m
ode
wit
h co
mm
and
pow
er r
edun
danc
y-m
ode
redu
ndan
t.
—V
iew
pow
er s
uppl
y se
ttin
gs u
sing
sho
w p
ower
.
•Fa
ns•
Hot
sw
ap m
odul
esTo
polo
gica
l red
unda
ncy:
•Pr
ovid
es r
edun
dant
sw
itch
ing
path
s so
the
re is
n’t
a si
ngle
poi
nt o
f fa
ilure
.•
Impl
emen
ts n
etw
ork
mon
itor
ing
to r
ecog
nize
fai
lure
s an
d re
pair
the
m.
•W
ith
redu
ndan
t pa
ths,
dev
ice
can
be o
fflin
e fo
r up
grad
es w
itho
ut d
isru
ptin
g ne
twor
k se
rvic
e.•
Doe
s no
t co
-loc
ate
devi
ces,
so
that
pro
blem
s in
the
spa
ce d
o no
t af
fect
mor
e th
an
a si
ngle
pie
ce o
f eq
uipm
ent.
Use
all
met
hods
to s
plit
traf
fic b
etw
een
redu
ndan
t pat
hs, i
ncre
asin
g ag
greg
ate
netw
ork
band
wid
th
Defa
ult
Gate
way R
ed
un
dan
cy
Gate
way D
isco
very
Spec
ifyi
ng a
def
ault
gat
eway
lead
s to
a s
ingl
e po
int
of f
ailu
re.
Man
y m
etho
ds e
xist
for
host
s to
dyn
amic
ally
dis
cove
r ga
tew
ays,
but
all
have
pro
blem
s.•
Prox
y A
RP
—H
ost
AR
Ps f
or a
ll de
stin
atio
ns, e
ven
rem
ote.
—R
oute
r re
spon
ds w
ith
its
MA
C.
—Pr
oble
m: S
low
fai
love
r be
caus
e A
RP
entr
ies
take
min
utes
to
tim
eout
.
•IC
MP
Rou
ter
Dis
cove
ry P
roto
col (
IRD
P)—
Rou
ters
use
IR
DP
to a
dver
tise
def
ault
rou
tes.
—IR
DP
adve
rtis
emen
ts h
ave
a lif
etim
e—If
the
life
tim
e ex
pire
s w
itho
ut h
eari
ng a
re
adve
rtis
emen
t, a
noth
er g
atew
ay is
cho
sen.
—Pr
oble
m: S
low
fai
love
r be
caus
e ad
vert
isem
ents
hav
e a
defa
ult
lifet
ime
of 3
0 m
inut
es.
•R
outi
ng p
roto
col
—PC
run
s ro
utin
g pr
otoc
ol t
o di
scov
er b
est
rout
es.
—U
sual
ly R
IP.
Ro
ute
r R
ed
un
dan
cy
Inst
ead
of m
akin
g th
e ho
st r
espo
nsib
le fo
r ch
oosi
ng a
new
gat
eway
, rou
ter
redu
ndan
cy
prot
ocol
s al
low
tw
o or
mor
e ro
uter
s to
sup
port
a s
hare
d M
AC
add
ress
. If
the
prim
ary
rout
er is
lost
, the
bac
kup
rout
er a
ssum
es c
ontr
ol o
f tr
affic
for
war
ded
to t
hat
MA
C.
Ho
t S
tan
db
y R
ou
ter
Pro
toco
l (H
SR
P)
•C
isco
pro
prie
tary
.•
Two
or m
ore
devi
ces
supp
ort
a vi
rtua
l rou
ter
wit
h m
ade
up M
AC
and
uni
que
IP
addr
ess.
•A
ctiv
e ro
uter
for
war
ds t
raffi
c.•
Stan
dby
is b
acku
p. M
onit
ors
peri
odic
hel
los
to d
etec
t A
ctiv
e fa
ilure
.•
Act
ive
rout
er is
cho
sen
beca
use
it h
as h
ighe
r H
SRP
prio
rity
(de
faul
t 10
0).
•A
new
rou
ter
wit
h a
high
er p
rior
ity
does
not
cau
se a
n el
ecti
on u
nles
s it
is c
onfig
-ur
ed t
o PR
EE
MPT
.•
Shar
ed M
AC
is 0
000.
0c07
.AC
xx, w
here
xx
is t
he H
SRP
grou
p.•
Mul
tipl
e gr
oups
(vi
rtua
l rou
ters
) al
low
ed.
•O
n fa
ilure
, sta
ndby
dev
ice
star
ts u
sing
IP
and
MA
C o
f th
e vi
rtua
l rou
ter.
•In
terf
ace
trac
king
allo
ws
prio
rity
to
chan
ge if
a c
onne
ctio
n is
lost
.•
HSR
P de
vice
s m
ove
betw
een
thes
e st
ates
:—
Init
ial—
HSR
P no
t ru
nnin
g.
—L
earn
—T
he r
oute
r do
es n
ot k
now
the
vir
tual
IP
addr
ess
and
is w
aiti
ng t
o he
ar
from
the
act
ive
rout
er.
—L
iste
n—R
oute
r kn
ows
IP a
nd M
AC
of
virt
ual r
oute
r, bu
t no
t th
e id
enti
ty o
f ot
her
HSR
P gr
oup
mem
bers
.
—Sp
eak—
Rou
ter
send
s pe
riod
HSR
P he
llos
and
elec
ts a
ctiv
e ro
uter
.
—St
andb
y—R
oute
r m
onit
ors
hello
s fr
om a
ctiv
e ro
uter
and
ass
umes
res
pons
ibili
ty
if a
ctiv
e ro
uter
fai
ls.
—A
ctiv
e—R
oute
r fo
rwar
ds p
acke
ts o
n be
half
of
the
virt
ual r
oute
r.
Con
figur
ing
HSR
P:•
Con
figur
e ro
uter
as
mem
ber
of H
SRP
grou
p 39
for
vir
tual
rou
ter
wit
h IP
10
.0.0
.1:
Router(config-if)# standby 39 ip 10.0.0.1
•C
onfig
ure
prio
rity
(de
faul
t 10
0, p
refe
rs h
ighe
st):
Router(config-if)# standby 39 priority 150
0910_BCMSNssf.fm Page 466 Tuesday, September 9, 2003 8:20 AM
Default Gateway Redundancy 467
•A
llow
rou
ter
to t
ake
over
if a
ctiv
e ro
uter
has
low
er p
rior
ity:
Router(config-if)# standby 39 preempt
•C
hang
e he
llo t
imer
to
2 se
cond
s an
d ho
ld t
imer
to
7 se
cond
s. C
an b
e se
t be
twee
n 1–
255
seco
nds
(def
ault
is h
ello
3 s
econ
ds a
nd h
old
10 s
econ
ds):
Router(config-if)# standby 39 timers 2 7
•T
rack
inte
rfac
e—If
ser
ial0
is d
own,
dec
rem
ent
HSR
P pr
iori
ty b
y 10
0:Router(config-if)# standby 39 track s0 100
NO
TE
Oth
er r
oute
rs m
ust
be c
onfig
ured
for
PR
EE
MPT
to
take
con
trol
.
•V
iew
HSR
P st
atus
:sssshhhhoooowwww ssssttttaaaannnnddddbbbbyyyy iiiinnnntttteeeerrrrffffaaaacccceeee ffffaaaasssstttteeeetttthhhh 0000////0000 oooo rrrr sssshhhhoooowwww ssssttttaaaannnnddddbbbbyyyy bbbbrrrriiiieeeeffff
•M
onit
or H
SRP
acti
vity
:ddddeeeebbbbuuuugggg ssssttttaaaannnnddddbbbbyyyy
Vir
tual
Rou
ter
Red
unda
ncy
Prot
ocol
(V
RR
P)•
Sim
ilar
to H
SRP,
but
ope
n st
anda
rd (
RFC
233
8).
•Tw
o or
mor
e de
vice
s su
ppor
t ei
ther
rea
l add
ress
es o
r vi
rtua
l rou
ter
addr
esse
s.•
Mas
ter
rout
er f
orw
ards
tra
ffic.
If
a re
al a
ddre
ss is
bei
ng s
uppo
rted
, ow
ner
of r
eal
addr
ess
mus
t be
mas
ter.
•B
acku
p ta
kes
over
if m
aste
r fa
ils. M
onit
ors
peri
odic
hel
los
to d
etec
t ac
tive
fai
lure
.•
Mas
ter
chos
en b
ecau
se 1
) it
ow
ns t
he r
eal a
ddre
ss o
r 2)
it h
as h
ighe
r pr
iori
ty
(def
ault
100
).•
Mul
tipl
e re
dund
anci
es (
real
or
virt
ual)
allo
wed
.G
atew
ay L
oad
Bal
anci
ng P
roto
col (
GL
BP)
•Si
mila
r to
HSR
P or
VR
RP,
but
sim
ulta
neou
s us
e of
gat
eway
s al
low
ed, m
axim
izin
g ba
ndw
idth
.•
Aut
omat
ical
ly d
etec
ts a
nd r
oute
s ar
ound
gat
eway
fai
lure
.•
Thr
ee m
odes
:—
Wei
ghte
d lo
ad b
alan
cing
—Tr
affic
is b
alan
ced
prop
ortio
nal t
o co
nfigu
red
wei
ght.
—H
ost-
depe
nden
t lo
ad b
alan
cing
—A
giv
en h
ost
alw
ays
uses
the
sam
e ro
uter
.
—R
ound
-rob
in lo
ad b
alan
cing
—E
ach
rout
er M
AC
use
d to
res
pond
to
AR
P re
ques
ts in
tur
n.
•A
ctiv
e V
irtu
al G
atew
ay (
AV
G o
r m
aste
r ga
tew
ay)
is t
he o
nly
rout
er t
o re
spon
d to
A
RPs
. It
uses
thi
s ca
paci
ty t
o ba
lanc
e lo
ad.
•G
LB
P ca
n tr
ack
inte
rfac
e; if
inte
rfac
e go
es d
own
AR
Ps r
edir
ect t
raffi
c to
oth
er r
oute
rs.
Sing
le R
oute
r M
ode
(SR
M):
•U
sed
by s
wit
ches
wit
h re
dund
ant
MSF
C2
card
s•
Onl
y on
e M
SFC
for
war
ds t
raffi
c•
If fi
rst
MSF
C f
ails
, bac
kup
star
ts. C
urre
nt F
IB u
sed
unti
l new
rou
ter
star
ts.
•B
oth
mus
t ru
n sa
me
IOS
and
have
sam
e co
nfigu
rati
onC
onfig
urin
g Si
ngle
Rou
ter
Mod
e (S
RM
)•
Ena
ble
redu
ndan
cy:
L3Switch(config)# redundancy
•E
nabl
e hi
gh a
vaila
bilit
y:L3Switch(config-r)# high-availability
•E
nabl
e SR
M:
L3Switch(config-r-ha)# single-router-mode
•V
erif
y:L3Switch# show redundancy
Serv
er L
oad
Bal
anci
ng (
SLB
)SL
B d
istr
ibut
es c
lient
req
uest
s be
twee
n se
vera
l ser
vers
. Clie
nts
send
tra
ffic
to a
sin
gle
virt
ual a
ddre
ss, a
nd S
LB
inte
llige
ntly
dis
trib
utes
req
uest
s to
the
gro
up.
•L
ight
er lo
ad o
n ea
ch s
erve
r re
sult
s in
bet
ter
perf
orm
ance
•Se
rver
fai
lure
s ar
e re
cogn
ized
, and
ser
ver
is r
emov
ed f
rom
gro
up u
ntil
rest
ored
.•
Indi
vidu
al s
erve
r m
ight
be
rem
oved
for
mai
nten
ance
.C
onfig
urin
g SL
B•
Defi
ne a
ser
ver
farm
nam
e:L3Switch(config)# ip slb serverfarm ponderosa
•Id
enti
fy r
eal s
erve
rs b
y IP
add
ress
:L3Switch(config-slb-sfarm)# real 10.1.2.3
•A
ctiv
ate
SLB
for
eac
h re
al s
erve
r:L3Switch(config-slb-real)# inservice
0910_BCMSNssf.fm Page 467 Tuesday, September 9, 2003 8:20 AM
468 BCMSN Quick Reference Sheets•
Vie
w t
he li
st o
f re
al s
erve
rs in
ser
ver
farm
:L3Switch# show ip slb real
•V
iew
sta
tus
of s
erve
r fa
rm:
L3Switch# show ip slb serverfarm
•D
efine
vir
tual
ser
ver
farm
nam
e:L3Switch(config)# ip slb vserver benjamin
•Id
enti
fy v
irtu
al s
erve
r IP
add
ress
:L3Switch(config-slb-vserver# virtual 202.101.100.9 255.255.255.0
•L
ink
virt
ual s
erve
r w
ith
serv
er f
arm
:L3Switch(config-slb-vserver)# serverfarm
•A
ctiv
ate
virt
ual s
erve
r:L3Switch(config-slb-vserver)# inservice
IP M
ult
icast
an
d IP
Tele
ph
on
y in
a
Sw
itch
ed
Netw
ork
A m
ulti
cast
is a
sin
gle
data
str
eam
sen
t fr
om o
ne s
ourc
e to
a g
roup
of
reci
pien
ts. I
n co
ntra
st, a
uni
cast
is t
raffi
c fr
om o
ne s
ourc
e to
one
des
tina
tion
. A b
road
cast
is t
raffi
c fr
om o
ne s
ourc
e to
all
dest
inat
ions
. Som
e fe
atur
es o
f m
ulti
cast
tra
ffic
are
as f
ollo
ws:
•Se
ndin
g ho
st d
oes
not k
now
the
iden
tity
of th
e re
ceiv
ing
host
s; th
ey a
re a
ll id
entifi
ed
by o
ne g
roup
IP
addr
ess.
•G
roup
mem
bers
hip
is d
ynam
ic. H
osts
join
a g
roup
, not
ify
thei
r up
stre
am r
oute
r, an
d th
e ro
uter
beg
ins
forw
ardi
ng d
ata
to t
hem
.•
Hos
ts c
an b
elon
g to
mor
e th
an o
ne g
roup
.•
Hos
ts in
a g
roup
can
be
loca
ted
in m
any
diff
eren
t pl
aces
.
Mu
ltic
ast
IP A
dd
resses
Mul
tica
sts
use
the
IP a
ddre
ss r
ange
of
224.
0.0.
0 to
239
.255
.255
.255
. The
firs
t fo
ur
bits
of
the
first
oct
et a
re a
lway
s bi
nary
111
0. T
he r
emai
ning
28
bits
iden
tify
the
mul
ti-
cast
gro
up. S
ome
addr
esse
s ar
e re
serv
ed:
•22
4.0.
0.1
is t
he a
ll-ho
sts
grou
p.•
224.
0.0.
2 is
the
all-
rout
ers
grou
p.•
The
res
t of
the
224
.0.0
.0/1
6 ra
nge
is r
eser
ved
for
netw
ork
prot
ocol
s.•
224.
0.1.
0 to
238
.255
.255
.255
are
for
use
ove
r th
e In
tern
et a
nd a
re c
alle
d gl
o-ba
lly-s
cope
d ad
dres
ses.
•So
urce
spe
cific
mul
tica
st u
ses
232.
0.0.
0 to
232
.255
.255
.255
add
ress
es.
•23
3.0.
0.0
to 2
33.2
55.2
55.2
55 a
re u
sed
to a
ssig
n a
stat
ic m
ulti
cast
add
ress
for
use
by a
n or
gani
zati
on. T
he s
econ
d an
d th
ird
octe
ts o
f th
e ad
dres
s ar
e th
e or
gani
za-
tion
’s a
uton
omou
s sy
stem
num
ber.
Thi
s is
cal
led
GL
OP—
a co
mbi
nati
on o
f glo
bal
and
scop
e.•
The
239
.0.0
.0 t
o 23
9.25
5.25
5.25
5 ra
nge
is f
or lo
cal u
se w
ithi
n an
org
aniz
atio
n.
The
y ar
e ca
lled
limit
ed s
cope
or
adm
inis
trat
ivel
y sc
oped
add
ress
es.
Mu
ltic
ast
Dis
trib
uti
on
Tre
es
Mul
tica
sts
use
two
diff
eren
t w
ays
to d
istr
ibut
e da
ta b
etw
een
a se
rver
and
hos
ts:
•A
sou
rce-
base
d tr
ee is
the
sim
ples
t ki
nd. I
ts r
oot
is t
he s
erve
r, an
d it
for
ms
bran
ches
out
thr
ough
the
net
wor
k to
all
the
mem
bers
of
the
mul
tica
st g
roup
. A
sour
ce t
ree
is id
enti
fied
by (
S,G
) w
here
S is
the
IP
addr
ess
of t
he s
erve
r an
d G
is
the
grou
p m
ulti
cast
add
ress
. It
crea
tes
opti
mal
pat
hs b
etw
een
the
serv
er a
nd t
he
host
s, b
ut ta
kes
mor
e ro
uter
res
ourc
es. E
very
rou
ter
alon
g th
e pa
th m
ust m
aint
ain
path
info
rmat
ion
for
ever
y se
rver
.•
A s
hare
d tr
ee s
elec
ts a
com
mon
roo
t, c
alle
d a
rend
ezvo
us p
oint
(R
P). T
he s
erve
r se
nds
traf
fic t
o th
e R
P, w
hich
for
war
ds it
tow
ard
host
s be
long
ing
to t
he g
roup
. T
he t
ree
is id
enti
fied
by (
*,G
) w
here
* m
eans
any
sou
rce
and
G is
the
gro
up m
ul-
tica
st a
ddre
ss. S
hare
d tr
ees
use
less
rou
ter
reso
urce
s, b
ut m
ight
res
ult
in s
ubop
ti-
mal
pat
hs.
Re
ve
rse
Pa
th F
orw
ard
ing
Mul
tica
st r
oute
rs id
enti
fy u
pstr
eam
por
ts (
poin
ting
tow
ard
the
serv
er o
r R
P) a
nd
dow
nstr
eam
por
ts (
poin
ting
tow
ard
othe
r re
ceiv
ers)
for
eac
h m
ulti
cast
gro
up. T
he
upst
ream
por
t is
fou
nd u
sing
Rev
erse
Pat
h Fo
rwar
ding
(R
PF).
RPF
invo
lves
look
ing
at
the
rout
ing
tabl
e to
see
whi
ch in
terf
ace
the
rout
er w
ould
use
to
send
uni
cast
tra
ffic
to
0910_BCMSNssf.fm Page 468 Tuesday, September 9, 2003 8:20 AM
IP Multicast and IP Telephony in a Switched Network 469th
at s
erve
r or
RP.
Tha
t in
terf
ace
is t
he u
pstr
eam
por
t, o
r R
PF p
ort,
for
tha
t m
ulti
cast
gr
oup.
The
RPF
che
ck is
don
e ev
ery
5 se
cond
s. I
t is
use
d in
thi
s w
ay:
•If
a m
ulti
cast
pac
ket
arri
ves
on t
he R
PF p
ort,
the
rou
ter
forw
ards
the
pac
ket
out
the
inte
rfac
es li
sted
in t
he o
utgo
ing
inte
rfac
e lis
t of
a m
ulti
cast
rou
ting
tab
le.
•If
the
pac
ket
does
not
arr
ive
on t
he R
PF p
ort,
the
pac
ket
is d
isca
rded
to
prev
ent
loop
s.
Pro
toco
l In
dep
en
den
t M
ult
icast
(PIM
)PI
M is
a p
roto
col u
sed
betw
een
rout
ers
to k
eep
trac
k of
whe
re t
o fo
rwar
d tr
affic
for
ea
ch m
ulti
cast
gro
up. I
t ca
n us
e in
form
atio
n ga
ther
ed f
rom
any
rou
ting
pro
toco
l. PI
M
can
run
in d
ense
mod
e or
spa
rse
mod
e.
PIM
Den
se M
od
e
PIM
den
se m
ode
uses
sou
rce-
base
d tr
ees.
Whe
n ru
nnin
g in
den
se m
ode,
PIM
ass
umes
th
at e
very
rou
ter
need
s to
rec
eive
mul
tica
sts.
Any
rou
ter
that
doe
sn’t
wan
t to
rec
eive
it
mus
t se
nd a
pru
ne m
essa
ge u
pstr
eam
tow
ard
the
serv
er. P
IM d
ense
mod
e is
mos
t ap
prop
riat
e w
hen:
•M
ulti
cast
ser
vers
and
rec
eive
rs a
re n
ear
each
oth
er.
•T
here
are
just
a f
ew s
erve
rs a
nd m
any
rece
iver
s.•
You
hav
e a
high
vol
ume
of m
ulti
cast
tra
ffic.
•T
he m
ulti
cast
str
eam
is f
airl
y co
nsta
nt.
PIM
Sp
ars
e M
od
e
PIM
spa
rse
mod
e us
es s
hare
d di
stri
buti
on t
rees
. It
does
not
ass
ume
that
any
rou
ters
w
ant
to r
ecei
ve t
he m
ulti
cast
, but
inst
ead
wai
ts t
o he
ar a
n ex
plic
it m
essa
ge f
rom
the
m,
join
ing
the
grou
p. T
hen,
it a
dds
bran
ches
to
the
tree
to
reac
h th
e ho
sts
behi
nd t
hose
ro
uter
s. P
IM s
pars
e m
ode
uses
ren
dezv
ous
poin
ts t
o co
nnec
t ho
sts
and
serv
ers.
Aft
er
the
conn
ecti
on is
mad
e, P
IM s
wit
ches
ove
r to
a s
ourc
e tr
ee. S
pars
e m
ode
is u
sed
whe
n:•
Pock
ets
of u
sers
are
wid
ely
disp
erse
d ar
ound
the
net
wor
k.•
Mul
tica
st t
raffi
c is
inte
rmit
tent
.
PIM
Sp
ars
e-D
en
se M
od
e
An
inte
rfac
e ca
n be
con
figur
ed in
spa
rse-
dens
e m
ode.
The
n, if
the
rout
er k
now
s of
a R
P fo
r it
s gr
oup,
it u
ses
spar
se m
ode.
Oth
erw
ise,
it u
ses
dens
e m
ode.
Add
itio
nally
, it
mak
es
the
inte
rfac
e ca
pabl
e of
rec
eivi
ng m
ulti
cast
s fr
om b
oth
spar
se a
nd d
ense
mod
e gr
oups
.
Co
nfi
gu
rin
g M
ult
icast
Ro
uti
ng
an
d P
IM•
Giv
e th
is c
omm
and
to e
nabl
e m
ulti
cast
rou
ting
:(config)# ip multicast routing
•PI
M m
ode
mus
t be
con
figur
ed a
t ea
ch in
terf
ace
wit
h th
e fo
llow
ing
com
man
d.
Con
figur
ing
PIM
on
an in
terf
ace
also
ena
bles
IG
MP
on t
hat
inte
rfac
e:(config-if)# ip pim {sparse-mode | dense-mode
| sparse-dense-mode}
•W
hen
usin
g sp
arse
mod
e, a
RP
mus
t be
spe
cifie
d. A
rou
ter
know
s th
at it
is a
n R
P w
hen
it s
ees
its
own
addr
ess
in t
he c
omm
and:
(config)# ip pim rp-address ip-address
Au
to-R
PA
uto-
RP
auto
mat
es t
he d
isco
very
of
RPs
in a
spa
rse
or s
pars
e-de
nse
PIM
net
wor
k.
RPs
adv
erti
se th
emse
lves
to a
rou
ter
desi
gnat
ed a
s an
RP
map
ping
age
nt. T
he m
appi
ng
agen
t th
en d
ecid
es o
n on
e R
P pe
r gr
oup
and
send
s th
at in
form
atio
n to
the
oth
er r
oute
rs.
•To
con
figur
e a
rout
er a
s an
RP,
typ
e(config)# ip pim send-rp-announce type number scope ttl group-list
access-list-number
•To
con
figur
e a
rout
er a
s a
map
ping
age
nt, t
ype
(config)# ip pim send-rp-discovery scope ttl
PIM
Vers
ion
2C
isco
rou
ters
wit
h re
cent
ver
sion
s of
the
IO
S us
e PI
M v
2 by
def
ault
. Som
e di
ffer
ence
s be
twee
n PI
M v
1 an
d PI
M v
2 in
clud
e th
e fo
llow
ing:
•PI
M v
1 is
Cis
co p
ropr
ieta
ry, w
here
as P
IM v
2 is
sta
ndar
ds-b
ased
.•
Bot
h ve
rsio
ns c
an d
ynam
ical
ly m
ap R
Ps t
o m
ulti
cast
gro
ups.
PIM
v1
uses
an
Aut
o-R
P m
appi
ng a
gent
; PIM
v2
uses
a b
oots
trap
rou
ter
(BSR
).•
PIM
v1
uses
a T
ime-
T22
22o-
Liv
e va
lue
to b
ound
its
anno
unce
men
ts, P
IM v
2 us
es
a confi
gure
d do
mai
n bo
rder
.•
In P
IM v
2, s
pars
e an
d de
nse
mod
e ar
e gr
oup
prop
erti
es, n
ot in
terf
ace
prop
erti
es.
To c
onfig
ure
PIM
v2,
con
figur
e at
leas
t on
e ro
uter
as
a B
SR a
nd s
elec
ted
rout
ers
as
RPs
. To
confi
gure
a B
SR:
(config)# ip pim bsr-candidate in
terface hash-mask-length [priority]
To c
onfig
ure
a ro
uter
as
a ca
ndid
ate
RP:
(config)# ip pim rp-candidate type number ttl group-list access-list-number
0910_BCMSNssf.fm Page 469 Tuesday, September 9, 2003 8:20 AM
470 BCMSN Quick Reference SheetsIn
tern
et
Gro
up
Man
ag
em
en
t P
roto
co
lW
hen
a ho
st w
ants
to
join
a m
ulti
cast
gro
up, i
t se
nds
an I
nter
net
Gro
up M
anag
emen
t Pr
otoc
ol (
IGM
P) m
essa
ge t
o th
e ro
uter
. The
rou
ter
peri
odic
ally
che
cks
for
grou
p m
em-
bers
on
each
seg
men
t. T
here
are
thr
ee v
ersi
ons
of I
GM
P.
IGM
P V
ers
ion
1
Mul
tica
st r
oute
rs q
uery
eac
h se
gmen
t pe
riod
ical
ly t
o se
e if
the
re a
re s
till
host
s in
mul
ti-
cast
gro
ups
wit
h a
quer
y se
nt t
o th
e al
l-ho
sts
addr
ess
of 2
24.0
.0.1
. One
hos
t on
the
se
gmen
t re
spon
ds. H
osts
sile
ntly
leav
e a
grou
p; t
he r
oute
r do
esn’
t kn
ow t
hey
are
gone
un
til i
t qu
erie
s an
d no
body
res
pond
s.
IGM
P V
ers
ion
2
Ver
sion
2 a
dds
expl
icit
leav
e m
essa
ges
that
hos
ts s
end
whe
n th
ey le
ave
a gr
oup.
Q
ueri
es a
re s
ent
to s
peci
fic m
ulti
cast
gro
up a
ddre
sses
, not
the
all-
host
s ad
dres
s.
IGM
P V
ers
ion
3
Hos
ts a
re a
ble
to t
ell t
he r
oute
r no
t on
ly w
hich
mul
tica
st g
roup
s th
ey b
elon
g to
, but
al
so w
hich
sou
rces
the
y ac
cept
mul
tica
sts
from
. It
adds
tw
o m
odes
for
req
uest
ing
mem
bers
hip
in a
mul
tica
st g
roup
:•
Incl
ude
mod
e—T
he r
ecei
ver
lists
the
grou
ps to
whi
ch it
bel
ongs
, and
the
serv
ers
it
uses
.•
Exc
lude
mod
e—T
he r
ecei
ver
lists
the
gro
up t
o w
hich
it b
elon
gs, a
nd t
he s
erve
rs it
do
esn’
t us
e.
Cis
co
Gro
up
Man
ag
em
en
t P
roto
co
l Sw
itch
es fl
ood
mul
tica
sts
by d
efau
lt. C
isco
Gro
up M
anag
emen
t Pr
otoc
ol (
CG
MP)
lets
a
rout
er t
ell a
sw
itch
whi
ch h
osts
bel
ong
to w
hich
mul
tica
st g
roup
, so
the
swit
ch c
an
add
that
info
rmat
ion
to it
s po
rt-t
o-M
AC
add
ress
map
ping
. The
n, w
hen
a m
ulti
cast
co
mes
in, t
he s
wit
ch f
orw
ards
it o
ut o
nly
to p
orts
tha
t ha
ve h
osts
bel
ongi
ng t
o th
at
grou
p. C
GM
P is
Cis
co p
ropr
ieta
ry.
IGM
P S
no
op
ing
IGM
P sn
oopi
ng is
ano
ther
way
for t
he sw
itch
to fi
nd o
ut w
hich
por
ts h
ave
mul
tica
st h
osts
. W
hen
it is
ena
bled
, the
sw
itch
ope
ns a
ll m
ulti
cast
pac
kets
, loo
king
for
IG
MP
join
or
lea
ve m
essa
ges.
Whe
n it
find
s on
e, i
t re
cord
s th
at i
nfor
mat
ion
and
uses
it
for
forw
ardi
ng m
ulti
cast
s. B
ecau
se e
very
mul
ti-
cast
pac
ket h
as to
be
open
ed, t
his
can
caus
e a
perf
orm
ance
hit
on
the
swit
ch.
Veri
fyin
g M
ult
icast
Ro
uti
ng
Som
e co
mm
ands
to v
erif
y m
ulti
cast
rou
ting
in
clud
e th
e fo
llow
ing:
•sh
ow ip
mro
ute—
Thi
s sh
ows
the
cont
ents
of t
he m
ultic
ast r
outin
g ta
ble.
For
eac
h gr
oup,
it li
sts
the
mod
e, th
e R
PF n
eigh
bor,
the
grou
p id
entifi
er, a
nd o
utgo
ing
inte
rfac
es.
•sh
ow ip
mro
ute
sum
mar
y—L
ists
eac
h m
ulti
cast
gro
up w
itho
ut a
s m
uch
deta
il.•
show
ip m
rout
e ac
tive
—Sh
ows
the
acti
ve s
ourc
es, a
nd t
he s
endi
ng r
ate
of e
ach.
•sh
ow ip
mro
ute
coun
t—Sh
ows
traf
fic s
tati
stic
s fo
r ea
ch m
ulti
cast
gro
up.
•sh
ow ip
pim
inte
rfac
e—L
ists
eac
h in
terf
ace
doin
g m
ulti
cast
ing,
its
PIM
mod
e, a
nd
num
ber
of n
eigh
bors
•sh
ow ip
pim
rp—
Lis
ts R
Ps t
he r
oute
r kn
ows
abou
t.•
show
ip p
im r
p-ha
sh—
Show
s th
e R
P se
lect
ed f
or e
ach
mul
tica
st g
roup
.•
show
ip p
im b
sr—
Lis
ts t
he c
urre
nt B
SR.
Cis
co
IP
Tele
ph
on
yPa
cket
loss
is o
ne o
f th
e bi
gges
t en
emie
s of
voi
ce t
rans
mis
sion
s, a
nd is
oft
en c
ause
d by
jitt
er a
nd c
onge
stio
n. J
itte
r (v
aria
ble
dela
y) c
ause
s bu
ffer
ove
r- a
nd u
nder
runs
. C
onge
stio
n at
the
inte
rfac
e ca
n be
cau
sed
by t
raffi
c fr
om a
fas
t po
rt b
eing
sw
itch
ed
to e
xit
out
a sl
ower
por
t, w
hich
cau
ses
the
tran
smit
buf
fer
to b
e ov
erru
n.
PIM
IGM
P
CG
MP
IGM
PS
noop
ing
0910_BCMSNssf.fm Page 470 Tuesday, September 9, 2003 8:20 AM
IP Multicast and IP Telephony in a Switched Network 471
Cis
co s
wit
ches
are
wel
l sui
ted
to s
uppo
rt b
oth
voic
e an
d vi
deo
tran
smis
sion
(AV
VID
) be
caus
e of
the
fol
low
ing
feat
ures
:•
The
y su
ppor
t m
ulti
ple
VL
AN
s on
eac
h ac
cess
por
t, b
y us
ing
Voi
ce V
LA
Ns.
Thi
s en
able
s th
e IP
Pho
nes
to b
elon
g to
a s
epar
ate
VL
AN
fro
m t
he c
ompu
ters
.•
The
y ca
n cl
assi
fy, m
ark,
and
pol
ice
traf
fic, a
s w
ell a
s pr
ovid
e di
ffer
enti
ated
que
uing
to
dif
fere
nt c
lass
es o
f tr
affic
.•
The
y ca
n be
con
figur
ed t
o tr
ust
the
QoS
mar
king
s pr
ovid
ed b
y th
e IP
pho
nes
or
othe
r de
vice
s.
Pre
pari
ng
th
e N
etw
ork
Whe
n ad
ding
voi
ce o
r vi
deo
to a
n ex
isti
ng n
etw
ork,
you
sho
uld
exam
ine
seve
ral t
hing
s in
adv
ance
:1.
Wha
t fe
atur
es a
re n
eede
d?—
Pow
er f
or I
P ph
ones
, voi
ce V
LA
Ns
on t
he s
wit
ches
, ne
twor
k re
dund
ancy
for
hig
h av
aila
bilit
y, s
ecur
ity
for
voic
e ca
lls, Q
oS s
etti
ngs.
2.T
he p
hysi
cal p
lant
—C
ablin
g at
leas
t C
AT-
5.3.
Ele
ctri
cal p
ower
for
the
IP p
hone
s—U
se e
ithe
r in
line
pow
er fr
om C
atal
yst s
wit
ch
or p
ower
pat
ch p
anel
. Nee
d un
inte
rrup
tibl
e po
wer
sup
ply
(UPS
) wit
h au
to-r
esta
rt,
mon
itor
ing,
and
4-h
our
resp
onse
con
trac
t. A
lso
gene
rato
r ba
ckup
. Mai
ntai
n co
rrec
t op
erat
ing
tem
pera
ture
s.4.
Ban
dwid
th—
Com
mit
no
mor
e th
an 7
5 pe
rcen
t of
ban
dwid
th. C
onsi
der
all t
ypes
of
tra
ffic—
voic
e, v
ideo
and
dat
a. H
ave
mor
e th
an e
noug
h ba
ndw
idth
if p
ossi
ble.
In
clud
e bo
th v
oice
and
cal
l-co
ntro
l tra
ffic
in y
our
plan
ning
.
Netw
ork
an
d B
an
dw
idth
Co
nsid
era
tio
ns
The
net
wor
k re
quir
emen
ts f
or V
oice
ove
r IP
(V
oIP)
incl
ude
•M
axim
um d
elay
of
150–
200
ms
(one
-way
)•
No
mor
e th
an 1
per
cent
pac
ket
loss
•M
axim
um a
vera
ge ji
tter
of
30 m
s•
Ban
dwid
th o
f 21
—10
6 kb
ps p
er c
all,
plus
abo
ut 1
50 b
ps p
er p
hone
for
con
trol
tr
affic
The
net
wor
k re
quir
emen
ts f
or s
trea
min
g vi
deo
incl
ude
•M
axim
um d
elay
of
4–5
sec
(one
-way
)•
No
mor
e th
an 2
per
cent
pac
ket
loss
•N
o jit
ter
requ
irem
ents
•B
andw
idth
nee
ded
depe
nds
on t
he v
ideo
str
eam
The
net
wor
k re
quir
emen
ts f
or v
ideo
con
fere
ncin
g in
clud
e•
Max
imum
del
ay o
f 15
0—20
0 m
s (o
ne-w
ay)
•N
o m
ore
than
1 p
erce
nt p
acke
t lo
ss•
Max
imum
ave
rage
jitt
er o
f 30
ms
•B
andw
idth
req
uire
d is
20
perc
ent
mor
e th
an t
he s
ize
of t
he v
ideo
conf
eren
cing
st
ream
A f
orm
ula
to u
se w
hen
calc
ulat
ing
band
wid
th n
eede
d fo
r vo
ice
calls
is a
s fo
llow
s:(P
acke
t pa
yloa
d +
all h
eade
r in
bit
s) *
Pac
ket
rate
per
sec
ond
Au
xilia
ry (
or
Vo
ice)
VLA
Ns
Cis
co s
wit
ches
can
be
confi
gure
d to
dyn
amic
ally
pla
ce I
P te
leph
ones
into
a V
LA
N s
ep-
arat
e fr
om t
he d
ata
VL
AN
s. T
hey
can
do t
his
even
whe
n th
e ph
one
and
PC a
re p
hysi
-ca
lly c
onne
cted
to
the
sam
e sw
itch
por
t. A
ter
m y
ou m
ight
see
is V
VID
—th
is is
the
vo
ice
VL
AN
ID
, whi
ch is
the
sam
e th
ing
as t
he n
umbe
r of
the
aux
iliar
y V
LA
N.
Voi
ce V
LA
Ns
allo
w p
hone
s to
be
dyna
mic
ally
pla
ced
in a
sep
arat
e IP
sub
net
from
ho
sts,
to
have
QoS
(us
ing
802.
1Q/p
hea
ders
) an
d se
curi
ty p
olic
ies
appl
ied,
and
mak
es
trou
bles
hoot
ing
easi
er.
Vo
ice in
th
e B
uild
ing
Access S
ub
mo
du
leIn
clud
e th
e fo
llow
ing
in t
he B
uild
ing
Acc
ess
Subm
odul
e w
hen
impl
emen
ting
VoI
P:•
Aux
iliar
y V
LA
Ns
•80
2.1p
/Q e
ncap
sula
tion
bet
wee
n th
e ph
one
and
the
swit
ch, w
hich
allo
ws
QoS
m
arki
ng•
Use
sw
itch
es t
hat
supp
ort
mul
tipl
e ou
tput
que
ues
•U
se s
wit
ches
tha
t su
ppor
t in
line
pow
er t
o IP
pho
nes
•C
onfig
ure
the
follo
win
g on
sw
itch
por
ts c
onne
cted
to
IP P
hone
s, a
nd in
the
net
-w
ork
in g
ener
al:
—ST
P Po
rt F
ast
—R
oot
Gua
rd
—U
nidi
rect
iona
l Lin
k D
etec
tion
(U
DL
D)
—U
plin
k Fa
st
Su
pp
ort
fo
r V
oic
e in
th
e B
uild
ing
Dis
trib
uti
on
Su
bm
od
ule
To s
uppo
rt V
oIP,
use
the
fol
low
ing
in t
he B
uild
ing
Dis
trib
utio
n Su
bmod
ule:
•M
ake
sure
VoI
P po
rts
do n
ot p
arti
cipa
te in
rou
ting
—ei
ther
use
pas
sive
inte
rfac
e or
con
figur
e th
e ne
twor
k st
atem
ents
und
er t
he r
outi
ng p
roto
cols
pro
perl
y.•
Use
HSR
P fo
r L
ayer
3 r
edun
danc
y.•
Tune
the
rou
ting
pro
toco
l to
allo
w f
or f
ast
dete
ctio
n of
a lo
st p
ath
and
quic
k co
nver
genc
e w
hen
the
netw
ork
chan
ges.
0910_BCMSNssf.fm Page 471 Tuesday, September 9, 2003 8:20 AM
472 BCMSN Quick Reference SheetsIm
ple
men
tin
g Q
oS
in
a S
wit
ch
ed
N
etw
ork
Qua
lity
of s
ervi
ce (
QoS
) co
nfigu
rati
ons
give
spe
cial
tre
atm
ent
to c
erta
in t
raffi
c at
the
ex
pens
e of
oth
ers.
Usi
ng Q
oS in
the
net
wor
k ad
dres
ses
thes
e pr
oble
ms:
•Pa
cket
loss
due
to
data
bei
ng d
ropp
ed a
t a
cong
este
d in
terf
ace
•D
elay
of
sens
itiv
e da
ta s
uch
as v
oice
and
vid
eo•
Jitt
er (
vari
able
del
ay)
Peop
le s
omet
imes
thi
nk t
hat
ther
e is
no
need
for
QoS
str
ateg
ies
in a
LA
N. H
owev
er,
swit
ch p
orts
can
exp
erie
nce
cong
esti
on b
ecau
se o
f po
rt s
peed
mis
mat
ches
, man
y pe
ople
tr
ying
to
acce
ss t
he s
wit
ch b
ackb
one,
and
man
y pe
ople
try
ing
to se
nd tr
affic
to th
e sa
me
switc
h po
rt (s
uch
as a
ser
ver
port
).QoS
is d
isab
led
by d
efau
lt on
sw
itche
s. It
is e
nabl
ed a
t the
in
terf
ace
confi
gura
tion
mod
e w
ith th
e fo
llow
ing
com
man
d:(config-if)# mls qos
Qo
S T
ech
niq
ues
Thr
ee Q
oS s
trat
egie
s ar
e co
mm
only
impl
emen
ted
on in
terf
aces
whe
re t
raffi
c en
ters
the
sw
itch
:•
Cla
ssifi
cati
on—
Dis
ting
uish
ing
one
type
of
traf
fic f
rom
ano
ther
. Aft
er t
raffi
c is
cl
assi
fied,
oth
er a
ctio
ns c
an b
e pe
rfor
med
on
it. E
xam
ples
: acc
ess
lists
, cla
ss m
aps,
N
BA
R.
•M
arki
ng—
Plac
ing
clas
s of
ser
vice
(C
oS),
IP
Prec
eden
ce, o
r D
iffS
erv
Cod
e Po
int
(DSC
P) v
alue
s on
the
cla
ssifi
ed t
raffi
c.•
Polic
ing—
Det
erm
inin
g w
heth
er o
r no
t a
spec
ific
type
of
traf
fic is
wit
hin
pres
et
band
wid
th le
vels
. If
so, i
t is
usu
ally
allo
wed
and
mig
ht b
e m
arke
d. I
f no
t, t
he t
raf-
fic is
typ
ical
ly m
arke
d or
dro
pped
. Exa
mpl
e: C
AR
and
cla
ss-b
ased
pol
icin
g.So
me
othe
r Q
oS t
echn
ique
s ar
e ty
pica
lly u
sed
on o
utbo
und
inte
rfac
es:
•T
raffi
c sh
apin
g an
d co
ndit
ioni
ng—
Att
empt
s to
sen
d tr
affic
out
in a
ste
ady
stre
am,
at a
spe
cifie
d ra
te. B
uffe
rs t
raffi
c th
at g
oes
abov
e th
at r
ate
and
send
s it
whe
n th
ere
is le
ss t
raffi
c on
the
line
.•
Que
uing
—O
nce
traf
fic is
cla
ssifi
ed a
nd m
arke
d, o
ne w
ay it
can
be
give
n sp
ecia
l tr
eatm
ent
is t
o be
put
into
dif
fere
nt q
ueue
s on
the
inte
rfac
e, t
o be
sen
t ou
t at
dif
-fe
rent
rat
es a
nd t
imes
. Exa
mpl
es: p
rior
ity
queu
ing,
wei
ghte
d fa
ir q
ueui
ng, c
usto
m
queu
ing.
The
def
ault
que
uing
met
hod
for
a sw
itch
por
t is
FIF
O.
•D
ropp
ing—
Nor
mal
ly, i
nter
face
que
ues
acce
pt p
acke
ts u
ntil
they
’re
full
and
then
dr
op e
very
thin
g af
ter
that
. You
can
impl
emen
t pr
iori
tize
d dr
oppi
ng, s
o th
at le
ss
impo
rtan
t pa
cket
s ar
e dr
oppe
d be
fore
mor
e im
port
ant
ones
. Exa
mpl
e: W
eigh
ted
Ran
dom
Ear
ly D
etec
tion
(W
RE
D).
Inte
gra
ted
Se
rvic
es (
IntS
erv
)In
tegr
ated
ser
vice
s is
a Q
oS m
odel
tha
t gu
aran
tees
a s
peci
fic a
mou
nt o
f ba
ndw
idth
to
the
iden
tifie
d tr
affic
, thr
ough
out
the
enti
re n
etw
ork.
A c
heck
is m
ade
of t
he p
ath
from
se
nder
to
rece
iver
, and
eac
h ro
uter
alo
ng t
he w
ay h
as t
o re
serv
e ba
ndw
idth
for
tha
t flo
w. T
his
is d
one
usin
g R
SVP—
Res
ourc
e R
eser
vati
on P
roto
col.
If t
he n
etw
ork
cann
ot
prov
ide
the
requ
ired
ban
dwid
th, t
he s
essi
on is
not
allo
wed
. RSV
P is
typ
ical
ly u
sed
for
voic
e ap
plic
atio
ns.
Dif
fere
nti
ate
d S
erv
ice
s (
Dif
fSe
rv)
Dif
fere
ntia
ted
serv
ices
pro
vide
leve
ls o
f se
rvic
e ba
sed
on t
he v
alue
of
cert
ain
bits
in t
he
IP o
r IS
L h
eade
r, or
the
802
.1Q
tag
. Eac
h ho
p al
ong
the
way
mus
t be
con
figur
ed t
o tr
eat
the
mar
ked
traf
fic t
he w
ay y
ou w
ant—
this
is c
alle
d pe
r-ho
p be
havi
or (
PHB
).•
In t
he L
ayer
3 I
P he
ader
, you
use
the
8-b
it T
oS fi
eld.
You
can
set
eit
her
IP P
rece
-de
nce,
usi
ng t
he t
op 3
bit
s, o
r D
iffe
rent
iate
d Se
rvic
es C
ode
Poin
ts (
DSC
P) u
sing
th
e to
p 6
bits
of t
he fi
eld.
The
bot
tom
2 b
its
are
not u
sed.
The
def
ault
DSC
P va
lue
is 0
, whi
ch c
orre
spon
ds t
o be
st-e
ffor
t de
liver
y.•
At
Lay
er 2
, wit
h IS
L, y
ou c
an s
et 3
of
the
4 bi
ts in
the
ISL
pri
orit
y fie
ld t
o se
t th
e cl
ass
of s
ervi
ce (
CoS
). W
ith
802.
1Q, y
ou s
et t
he 3
802
.1p
bits
to
the
CO
S. T
he
valu
es o
f th
ese
3 bi
ts c
orre
spon
d to
the
IP
Prec
eden
ce v
alue
s.
IP P
rece
de
nce
/Cla
ss o
f S
erv
ice
Usi
ng t
hree
bit
s fo
r IP
Pre
cede
nce
give
s yo
u 8
poss
ible
val
ues.
The
fol
low
ing
tabl
e sh
ows
the
valu
es a
nd t
heir
mea
ning
. Pre
cede
nce
5 is
usu
ally
use
d fo
r vo
ice
traf
fic; 6
an
d 7
are
rese
rved
for
suc
h th
ings
as
rout
ing
prot
ocol
s. N
orm
al d
ata
is t
ypic
ally
giv
en
Prec
eden
ce 0
. The
se s
ame
valu
es a
pply
for
CoS
bit
s al
so.
Pre
ced
en
ce/C
oS
Na
me
7N
etw
ork
6In
tern
et
5C
riti
cal
0910_BCMSNssf.fm Page 472 Tuesday, September 9, 2003 8:20 AM
Implementing QoS in a Switched Network 473
Tra
nsla
tin
g B
etw
een
DS
CP
an
d C
oS
Whe
n tr
affic
com
es in
to t
he s
wit
ch a
lrea
dy m
arke
d w
ith
a C
OS
or I
P Pr
eced
ence
val
ue
and
the
swit
ch tr
usts
that
, it a
ssig
ns a
DSC
P va
lue
for
its
own
inte
rnal
use
. If t
he fr
ame
has
an e
xist
ing
DSC
P va
lue
and
the
swit
ch t
rust
s th
at, i
t as
sign
s th
e sa
me
valu
e fo
r th
e in
tern
al D
SCP.
Sim
ilarl
y, th
e sw
itch
can
also
tran
slat
e a
DSC
P va
lue
into
a C
oS s
ettin
g w
hen
send
ing
data
out
a tr
unk
port
. The
def
ault
CoS
to D
SCP
map
ping
s ar
e sh
own
in th
is ta
ble:
The
def
ault
map
ping
s of
DC
SP t
o C
OS
are
show
n in
thi
s ta
ble:
Dif
fSe
rv A
ssu
red
Fo
rwa
rdin
gT
he 6
DSC
P bi
ts c
an b
e br
oken
dow
n in
to tw
o se
ctio
ns: t
he fi
rst 3
bits
defi
ne th
e D
iffSe
rv
Ass
ured
For
war
ding
(A
F) c
lass
, and
the
nex
t 2
bits
defi
ne t
he d
rop
prob
abili
ty w
ithi
n th
at c
lass
. The
six
th b
it is
0 a
nd u
nuse
d. A
F cl
asse
s 1–
4 ar
e de
fined
, and
wit
hin
each
cl
ass,
1 is
low
dro
p pr
obab
ility
, 2 is
med
ium
, and
3 is
hig
h (m
eani
ng t
hat
traf
fic is
m
ore
likel
y to
get
dro
pped
if th
ere
is c
onge
stio
n). E
ach
hop
still
nee
ds to
be
confi
gure
d fo
r ho
w t
o tr
eat
each
AF
clas
s.
Dif
fSe
rv E
xp
ed
ite
d F
orw
ard
ing
Ano
ther
pre
defin
ed D
iffSe
rv c
lass
ifica
tion
is E
xped
ited
Forw
ardi
ng (E
F). T
his
is e
quiv
alen
t to
DSC
P 46
and
is f
or u
se b
y yo
ur h
ighe
st p
rior
ity
traf
fic, s
uch
as v
oice
. You
con
figur
e ea
ch h
op in
the
net
wor
k fo
r th
e ty
pe o
f se
rvic
e yo
u w
ant
EF
traf
fic t
o re
ceiv
e.
Cla
ssif
yin
g T
raffi
c a
nd
Mark
ing
fo
r Q
oS
Mar
k tr
affic
for
QoS
as
clos
e to
the
sou
rce
as p
ossi
ble.
If
the
sour
ce is
an
IP t
elep
hone
, it
can
mar
k it
s ow
n tr
affic
. If
not,
the
bui
ldin
g ac
cess
mod
ule
swit
ch c
an d
o th
e m
ark-
ing.
If
thos
e ar
e no
t un
der
your
con
trol
, you
mig
ht n
eed
to m
ark
at t
he d
istr
ibut
ion
laye
r. C
lass
ifyi
ng a
nd m
arki
ng s
low
s tr
affic
flow
, so
don’
t do
it a
t th
e co
re. A
ll de
vice
s al
ong
the
path
sho
uld
then
be
confi
gure
d to
tru
st t
he m
arki
ng a
nd p
rovi
de a
leve
l of
Pre
ced
en
ce/C
oS
Nam
e
4Fl
ash-
over
ride
3Fl
ash
2Im
med
iate
1Pr
iori
ty
0R
outi
ne
Co
SD
SC
PC
oS
DS
CP
00
432
18
540
216
648
324
756
DS
CP
Co
S
0–7
0
8–15
1
16–2
32
24–3
13
DS
CP
Co
S
32–3
94
40–4
75
48–5
56
56–6
37
Lo
w D
rop
Me
diu
m D
rop
Hig
h D
rop
Cla
ss 1
AF1
1A
F12
AF1
3
Cla
ss 2
AF2
1A
F22
AF2
3
Cla
ss 3
AF3
1A
F32
AF3
3
Cla
ss 4
AF4
1A
F42
AF4
3
0910_BCMSNssf.fm Page 473 Tuesday, September 9, 2003 8:20 AM
474 BCMSN Quick Reference Sheetsse
rvic
e ba
sed
on it
. The
pla
ce w
here
tru
sted
mar
king
is d
one
is c
alle
d th
e tr
ust
boun
d-ar
y. T
o co
nfigu
re a
sw
itch
to
trus
t th
e m
arki
ngs
at a
n in
terf
ace:
(config-if)#mls qos trust {dscp
| cos}
Whe
n IP
tra
ffic
com
es in
alr
eady
mar
ked,
the
sw
itch
has
som
e op
tion
s ab
out
how
to
hand
le it
. It
can
•T
rust
the
DSC
P va
lue
in t
he in
com
ing
pack
et, i
f pr
esen
t•
Tru
st t
he I
P Pr
eced
ence
val
ue in
the
inco
min
g pa
cket
, if
pres
ent
•T
rust
the
CoS
val
ue in
the
inco
min
g fr
ame,
if p
rese
nt•
Cla
ssif
y th
e tr
affic
bas
ed o
n an
IP
acce
ss c
ontr
ol li
st, o
r a
MA
C a
ddre
ss A
CL
Han
dlin
g N
on
-IP
Tra
ffic
Non
-IP
traf
fic d
oes
not
have
fiel
ds in
the
hea
der
for
Type
of
Serv
ice.
The
sw
itch
can
ha
ndle
thi
s in
the
fol
low
ing
way
s:•
Use
the
def
ault
por
t C
oS v
alue
if t
he f
ram
e do
es n
ot h
ave
a va
lue
assi
gned
•T
rust
the
alr
eady
-ass
igne
d C
oS v
alue
in t
he in
com
ing
fram
e, if
pre
sent
•C
lass
ify
the
traf
fic b
ased
on
a M
AC
add
ress
acc
ess
cont
rol l
ist
Cla
ssif
yin
g a
nd
Mark
ing
Usin
g M
QC
Mod
ular
QoS
com
man
d-lin
e in
terf
ace
(MQ
C)
is a
met
hod
of c
lass
ifyi
ng t
raffi
c, m
ark-
ing
the
traf
fic, a
nd s
etti
ng p
olic
ies
for
that
traf
fic th
at c
an b
e us
ed o
n m
ost d
evic
es w
ith
mos
t ki
nds
of p
olic
ies.
Her
e ar
e th
e ge
nera
l ste
ps:
1.C
reat
e th
e ne
cess
ary
acce
ss c
ontr
ol li
sts,
if c
lass
ifyi
ng tr
affic
by
AC
L, o
r co
nfigu
re
NB
AR
if y
our
swit
ch s
uppo
rts
that
(e.
g., 6
500)
.2.
Cre
ate
the
clas
s m
aps
that
spe
cify
mat
chin
g su
ch t
hing
s as
AC
Ls,
pro
toco
l, D
SCPs
, or
IP P
rece
denc
e va
lues
.3.
Cre
ate
a po
licy
map
tha
t ca
lls e
ach
clas
s m
ap a
nd d
efine
s th
e po
licy
for
each
.4.
App
ly t
he p
olic
y m
ap t
o th
e ap
prop
riat
e sw
itch
por
ts.
Whe
n ac
cess
con
trol
list
s (A
CL
s) a
re u
sed
to c
lass
ify
traf
fic, t
he w
ay a
sw
itch
rea
cts
to
spec
ific
acce
ss c
ontr
ol e
ntri
es (
AC
Es)
is d
iffe
rent
in a
QoS
con
text
tha
n w
ith
secu
rity
-ba
sed
AC
Ls.
In
a Q
oS a
cces
s lis
t,•
If t
he t
raffi
c m
atch
es a
per
mit
sta
tem
ent,
the
des
igna
ted
QoS
act
ion
is t
aken
•If
the
tra
ffic
mat
ches
a d
eny
stat
emen
t, t
he r
est
of t
he A
CE
s in
tha
t A
CL
are
sk
ippe
d, a
nd t
he s
wit
ch g
oes
to t
he n
ext
AC
L.
•If
the
re a
re m
ulti
ple
AC
Ls
in a
pol
icy
appl
ied
to a
n in
terf
ace,
the
sw
itch
sto
ps
read
ing
them
as
soon
as
a pe
rmit
sta
tem
ent
mat
ch is
fou
nd f
or t
he t
raffi
c.
•If
the
tra
ffic
does
not
mat
ch a
ny A
CL
ent
ry, t
he s
wit
ch ju
st g
ives
bes
t-ef
fort
del
iv-
ery
to t
he t
raffi
c.
Co
nfi
gu
rin
g M
QC
Firs
t, c
onfig
ure
the
acce
ss li
sts
if u
sing
the
m.
Seco
nd, c
onfig
ure
a cl
ass
map
for
eac
h cl
assi
ficat
ion
of t
raffi
c:(config)# class-map [match-any
| match-all] name
(config-cmap)# match match options, such as ACL
Thi
rd, c
onfig
ure
a po
licy
map
tha
t ca
lls t
he c
lass
map
s an
d se
ts p
olic
ies
or t
ypes
of
trea
tmen
t fo
r ea
ch c
lass
:(config)#policy-map name
(config-pmap)#class class-map name
(config-pmap-c)#policy options, such as set DSCP
Fina
lly, a
pply
the
MQ
C p
olic
y to
the
des
ired
inte
rfac
e(s)
, eit
her
inbo
und
or o
utbo
und.
N
ote:
Pol
icy
map
s th
at c
lass
ify
traf
fic u
sing
AC
Ls,
tha
t se
t D
SCP
or I
P Pr
eced
ence
, or
that
tel
l the
inte
rfac
e to
tru
st e
xist
ing
mar
king
s ca
n be
app
lied
only
inbo
und.
(config-if)#service-policy {output
| input} name
Qu
eu
ing
Meth
od
s
FIF
O (
Fir
st-
In, Fir
st-
Ou
t)
The
def
ault
on
swit
ch p
orts
. If Q
oS is
not
ena
bled
, the
re is
one
sof
twar
e qu
eue.
If Q
oS is
en
able
d, t
here
are
fou
r so
ftw
are
queu
es p
er p
ort,
but
the
y ar
e al
l wei
ghte
d an
d se
rvic
ed
equa
lly, w
ith
best
-eff
ort
deliv
ery.
Tra
ffic
is p
lace
d in
the
m b
ased
on
CoS
val
ue:
Que
ue 1
—C
oS v
alue
s 0
and
1Q
ueue
2—
CoS
val
ues
2 an
d 3
Que
ue 3
—C
oS v
alue
s 4
and
5Q
ueue
4—
CoS
val
ues
6 an
d 7
Pri
ori
ty Q
ueu
ing
(P
Q)
Que
ues
are
assi
gned
dif
fere
nt p
rior
ity
valu
es, a
nd t
he h
igh
prio
rity
que
ue g
ets
serv
iced
be
fore
any
thin
g el
se. P
rior
ity
queu
ing
is d
one
on t
he 3
550
usin
g th
e ex
pedi
te q
ueue
, w
hich
is a
str
ict
prio
rity
que
ue. I
t is
ser
vice
d ah
ead
of t
he o
ther
que
ues
unti
l it
is
empt
y. T
his
queu
e is
con
figur
ed o
n th
e 35
50 a
t in
terf
ace
confi
gura
tion
mod
e w
ith
the
com
man
d: p
rior
ity-
queu
e ou
t.
0910_BCMSNssf.fm Page 474 Tuesday, September 9, 2003 8:20 AM
Implementing QoS in a Switched Network 475
Cu
sto
m Q
ueu
ing
(C
Q)
Res
erve
s a
part
of
the
inte
rfac
e ba
ndw
idth
for
the
dif
fere
nt q
ueue
s. C
an c
lass
ify
and
plac
e sp
ecifi
c tr
affic
into
the
que
ues.
Weig
hte
d F
air
Qu
eu
ing
(W
FQ
)
Giv
es w
eigh
ts t
o di
ffer
ent
type
s of
tra
ffic,
and
allo
ws
low
er w
eigh
ted
traf
fic m
ore
band
wid
th. T
raffi
c ca
n be
wei
ghte
d by
flow
(co
nver
sati
on)
or u
sing
cla
ss m
aps.
Lo
w L
ate
ncy Q
ueu
ing
(LLQ
)
Has
one
pri
ority
que
ue a
nd u
sual
ly v
oice
traf
fic is
put
into
this
. Use
s cl
ass-
base
d W
FQ fo
r th
e re
st o
f the
inte
rfac
e tr
affic
. Con
figur
e th
is u
nder
the
clas
s st
atem
ent i
n th
e po
licy
map
:(config-pmap-c)# priority bandwidth
IP R
TP
Pri
ori
ty
Is s
imila
r to
LL
Q in
that
is h
as a
pri
ority
que
ue a
nd u
ses
WFQ
for
othe
r tr
affic
. How
ever
, he
re t
he p
rior
ity
queu
e is
com
plet
ely
for
voic
e tr
affic
. RT
P is
Rea
l Tim
e Pr
otoc
ol, t
he
prot
ocol
use
d by
Voi
ce o
ver
IP. I
t is
con
figur
ed a
t th
e in
terf
ace:
(config-if)# ip rtp priority start-port po
rt-range BW
Weig
hte
d R
ou
nd
Ro
bin
(W
RR
)
Thi
s is
the
proc
ess
that
take
s pa
cket
s fr
om th
e qu
eues
, dec
ides
whi
ch q
ueue
goe
s w
hen,
an
d ho
w m
any
pack
ets
can
be s
ent f
rom
eac
h qu
eue
at a
tim
e. D
urin
g tim
es o
f int
erfa
ce
cong
esti
on, W
RR
wei
ghts
que
ues,
and
mor
e pa
cket
s ar
e se
nt f
rom
hig
her
wei
ghte
d qu
eues
, thu
s gi
ving
the
m m
ore
band
wid
th.
Wh
at
Hap
pen
s W
hen
th
e S
oft
ware
Qu
eu
es G
et
Fu
ll?
By
defa
ult,
whe
n a
soft
war
e qu
eue
is f
ull (
cong
este
d) t
he s
wit
ch ju
st d
rops
all
othe
r tr
affic
bou
nd f
or t
hat
queu
e. T
his
is c
alle
d ta
il dr
op. I
t ca
n ca
use
som
e pr
oble
ms:
•T
CP
glob
al s
ynch
roni
zati
on.
•T
CP
buff
er s
tarv
atio
n.•
Del
ay a
nd ji
tter
.•
Hig
h pr
iori
ty t
raffi
c is
dro
pped
whi
le lo
w p
rior
ity
traf
fic is
sen
t.C
onge
stio
n av
oida
nce
is a
ccom
plis
hed
by u
sing
Wei
ghte
d R
ando
m E
arly
Det
ecti
on
(WR
ED
). W
RE
D s
tart
s dr
oppi
ng lo
wer
pri
ority
traf
fic (b
ased
on
DSC
P or
IP P
rece
denc
e va
lues
) as
the
queu
e st
arts
to fi
ll, a
nd d
rops
hig
h pr
iori
ty tr
affic
onl
y w
hen
the
queu
e is
al
mos
t fu
ll. T
he d
rop
thre
shol
ds a
nd t
he d
rop
rati
os a
re c
onfig
urab
le. W
RE
D w
orks
be
st w
ith
TC
P tr
affic
, bec
ause
TC
P dy
nam
ical
ly a
djus
ts it
s se
ndin
g ra
te w
hen
pack
ets
are
drop
ped.
Do
not u
se W
RE
D fo
r vo
ice
traf
fic. I
f the
que
ue fi
lls c
ompl
etel
y, ta
il dr
op
is u
sed.
On
the
3550
, the
gig
abit
Eth
erne
t po
rts
can
use
eith
er t
ail d
rop
or W
RE
D (
Wei
ghte
d R
ando
m E
arly
Det
ecti
on).
The
10/
100
port
s ca
n us
e on
ly t
ail d
rop.
WR
ED
is e
nabl
ed
eith
er in
a p
olic
y m
ap o
r at
the
inte
rfac
e—th
e co
mm
and
is t
he s
ame:
rrrraaaannnnddddoooommmm----ddddeeeetttteeeecccctttt ddddssssccccpppp----bbbbaaaasssseeeedddd
Tra
ffic P
olicin
gB
y us
ing
the
QoS
pol
icin
g fu
ncti
on, b
andw
idth
use
can
be
cont
rolle
d on
phy
sica
l int
er-
face
s in
the
swit
ch. T
raffi
c ca
nnot
be
polic
ed p
er V
LA
N o
r on
an
SVI.
Pol
icin
g sp
ecifi
es
an a
mou
nt o
f ba
ndw
idth
allo
wed
for
a p
arti
cula
r ty
pe o
f tr
affic
, and
gen
eral
ly d
rops
tr
affic
ove
r th
at a
mou
nt. I
t ca
n al
so b
e co
nfigu
red
to a
llow
the
exc
ess
traf
fic, b
ut m
ark
it w
ith
a di
ffer
ent
DSC
P va
lue.
The
355
0 sw
itch
can
pol
ice
band
wid
th u
se e
ithe
r fo
r ea
ch in
divi
dual
cla
ss o
f tr
affic
(i
ndiv
idua
l pol
icin
g), o
r it
can
lim
it b
andw
idth
use
for
all
traf
fic (
aggr
egat
e po
licin
g).
Tra
ffic S
hap
ing
Tra
ffic
shap
ing
also
con
trol
s th
e am
ount
of
traf
fic u
sed
by a
spe
cifie
d ty
pe o
f tr
affic
, bu
t sh
apin
g bu
ffer
s th
e ex
cess
tra
ffic
inst
ead
of d
ropp
ing
it. B
ecau
se d
ata
is u
sual
ly
burs
ty, t
he b
uffe
red
traf
fic c
an b
e se
nt o
ut b
etw
een
burs
ts. I
t th
us s
moo
thes
out
the
flo
w o
f tr
affic
.
Cre
ati
ng
Ban
dw
idth
by C
om
pre
ssio
nC
ompr
essi
ng t
he t
raffi
c on
a li
ne c
reat
es m
ore
usea
ble
band
wid
th; b
ecau
se e
ach
fram
e is
sm
alle
r, th
ere
are
few
er b
its
to t
rans
mit
. You
can
com
pres
s th
e w
hole
pay
load
, or
just
com
pres
s th
e pr
otoc
ol h
eade
rs w
ith
TC
P or
RT
P he
ader
com
pres
sion
. Cis
co
supp
orts
thr
ee L
ayer
2 p
aylo
ad c
ompr
essi
on a
lgor
ithm
s:•
Stac
ker
•Pr
edic
tor
•M
icro
soft
Poi
nt-t
o-Po
int
Com
pres
sion
(M
PPC
)
Lin
k F
rag
men
tati
on
an
d In
terl
eave (
LFI)
A ty
pica
l net
wor
k ha
s a
rang
e of
pac
ket s
izes
. Sm
all p
acke
ts c
an b
e de
laye
d w
aiti
ng fo
r a
larg
e pa
cket
to
be s
ent
out
the
inte
rfac
e. L
FI b
reak
s la
rge
pack
ets
into
sm
alle
r se
g-m
ents
and
inte
rspe
rses
the
sm
alle
r pa
cket
s be
twee
n th
e pi
eces
of
the
big
ones
. Thi
s re
duce
s de
lay
and
jitte
r.
0910_BCMSNssf.fm Page 475 Tuesday, September 9, 2003 8:20 AM
476 BCMSN Quick Reference SheetsIn
sum
mar
y, o
ptio
ns t
hat
are
avai
labl
e to
you
whe
n co
nfigu
ring
a s
wit
ch’s
outb
ound
(e
gres
s) q
ueue
s in
clud
e•
Cha
ngin
g th
e C
oS-t
o-qu
eue
map
•A
ssig
ning
dro
p th
resh
olds
to
each
que
ue•
Map
ping
DSC
Ps t
o th
e dr
op t
hres
hold
s•
Ena
blin
g ei
ther
WR
ED
or
tail
drop
•C
hang
ing
the
size
of
buff
er s
pace
allo
tted
to
each
que
ue•
Cha
ngin
g th
e re
lati
ve w
eigh
t of
eac
h qu
eue
Qo
S a
t th
e B
uild
ing
Access L
ayer
Ena
ble
QoS
at t
he b
uild
ing
acce
ss la
yer,
then
cla
ssify
and
mar
k th
e tr
affic
, and
per
haps
do
polic
ing.
If t
he t
raffi
c is
alr
eady
cla
ssifi
ed b
y a
trus
ted
end
stat
ion,
con
figur
e th
e sw
itch
to
tru
st t
he m
arki
ngs.
Con
figur
e vo
ice
VL
AN
s if
usi
ng I
P ph
ones
.
Qo
S a
t th
e B
uild
ing
Dis
trib
uti
on
Layer
Ena
ble
QoS
at t
he b
uild
ing
dist
ribu
tion
laye
r an
d th
en c
onfig
ure
the
swit
ch to
trus
t the
pr
iori
ty m
arki
ng it
rec
eive
s fr
om t
he a
cces
s la
yer
swit
ches
. If
the
mar
king
s ar
e fr
om a
n un
trus
ted
sour
ce, c
onfig
ure
the
swit
ch t
o ov
erri
de t
hem
. You
mig
ht t
hen
wan
t to
mod
-if
y th
e sw
itch
’s de
faul
t pe
r-ho
p be
havi
or b
ased
on
thes
e va
lues
. If
usin
g W
RE
D, y
ou
mig
ht c
hang
e th
e D
SCP-
to-t
hres
hold
map
ping
s. Y
ou m
ight
als
o ch
ange
the
DSC
P-to
-C
oS m
appi
ngs,
to p
ut tr
affic
in d
iffe
rent
egr
ess
queu
es. L
astl
y, y
ou ty
pica
lly c
hang
e th
e re
lati
ve w
eigh
ts o
f th
e qu
eues
on
the
egre
ss in
terf
ace.
Qo
S a
t th
e C
am
pu
s B
ackb
on
eN
o cl
assi
ficat
ion
or m
arki
ng s
houl
d be
don
e at
the
core
laye
r, as
this
slo
ws
dow
n tr
affic
. A
cong
esti
on a
void
ance
mec
hani
sm s
uch
as W
RE
D m
ight
be
used
, alo
ng w
ith
inte
rfac
e qu
euin
g te
chni
ques
suc
h as
cla
ss-b
ased
wei
ghte
d fa
ir q
ueui
ng o
r lo
w la
tenc
y qu
euin
g to
gu
aran
tee
band
wid
th t
o cr
itic
al a
pplic
atio
ns.
Qo
S f
or
Vo
ice o
ver
IPIn
a n
etw
ork
wit
h vo
ice
traf
fic, c
onfig
ure
eith
er t
he e
nd s
tati
ons
or t
he s
wit
ch t
o m
ark
the
voic
e tr
affic
wit
h IP
Pre
cede
nce
5 or
DSC
P 46
. Con
figur
e th
e eg
ress
inte
rfac
e fo
r pr
iori
ty q
ueui
ng, t
hen
confi
gure
the
DSC
P-to
-CoS
map
ping
s to
put
the
voi
ce t
raffi
c in
th
e E
xped
ite
queu
e (o
n th
e 35
50)
or t
he h
ighe
st p
rior
ity
queu
e (o
n th
e 29
50).
Veri
fyin
g Q
oS
Use
the
fol
low
ing
com
man
ds t
o ve
rify
you
r Q
oS c
onfig
urat
ions
and
act
ions
:•
show
cla
ss-m
ap [
nam
e]—
Dis
play
s th
e co
nfigu
red
clas
s m
aps,
or
just
the
one
na
med
.•
show
pol
icy-
map
[na
me]
—D
ispl
ays
the
confi
gure
d po
licy
map
s, o
r ju
st t
he o
ne
nam
ed.
•sh
ow p
olic
y-m
ap [
inte
rfac
e [in
terf
ace-
spec
[in
put
| out
put]
[ c
lass
cla
ss-n
ame]
]]—
Dis
play
s th
e po
licy
map
s an
d st
atis
tics
by
inte
rfac
e an
d/or
cla
ss.
•sh
ow q
ueue
ing
[inte
rfac
e in
terf
ace-
no.]—
Show
s th
e qu
euin
g st
rate
gy a
nd s
tati
stic
s fo
r an
y qu
eues
con
figur
ed o
n th
e in
terf
ace.
•sh
ow p
olic
y in
terf
ace
inte
rfac
e-no
.—D
ispl
ays
the
polic
ies
for
all c
lass
es a
pplie
d to
th
e in
terf
ace,
alo
ng w
ith
stat
isti
cs.
•de
bug
ip r
svp—
If u
sing
RSV
P fo
r vo
ice,
sho
ws
info
rmat
ion
abou
t pa
cket
s re
ceiv
ed a
nd s
ent.
•de
bug
prio
rity
—Sh
ows
info
rmat
ion
on t
he p
rior
ity
queu
e.
Op
tim
izin
g P
erf
orm
an
ce o
f C
am
pu
s
Netw
ork
s
Te
ch
niq
ue
s t
o O
pti
miz
e P
erf
orm
an
ce
•M
onit
or n
etw
ork
cont
inuo
usly
•U
nder
stan
d no
min
al b
ehav
ior
(bas
elin
e)—
Uti
lizat
ion
—R
espo
nse
tim
es
—E
rror
s
•A
ntic
ipat
e ca
paci
ty is
sues
—N
ew h
ardw
are
or c
ircu
its
can
take
wee
ks t
o be
in
stal
led
Pro
toco
l A
naly
sis
to
ols
in
Cis
co
sw
itch
es
Swit
ched
Por
t A
naly
zer
(SPA
N)
•C
opie
s ne
twor
k tr
affic
from
a s
witc
h po
rt o
r V
LA
N to
a li
sten
ing
port
. Can
mon
itor
inco
min
g, o
utgo
ing,
or
both
.•
Cap
ture
s th
e tr
affic
wit
h a
prot
ocol
ana
lyze
r (s
uch
as S
niff
er o
r E
ther
eal)
att
ache
d to
list
enin
g po
rt.
0910_BCMSNssf.fm Page 476 Tuesday, September 9, 2003 8:20 AM
Security in the Campus Network 477
•M
ulti
ple
SPA
N s
essi
ons
are
supp
orte
d.•
The
follo
win
g ex
ampl
e co
nfigu
res
SPA
N to
cop
y tr
affic
from
por
t fas
teth
erne
t 2/2
(i
ncom
ing
and
outg
oing
) to
fas
teth
erne
t 2/
48 a
s se
ssio
n nu
mbe
r 7.
L3Switch(config)# monitor session 7 source interface fastethernet 2/2 both
L3Switch(config)# monitor session 7 destination interface fastethernet 2/48
VL
AN
-Bas
ed S
PAN
(V
SPA
N)
•Sa
me
idea
as
SPA
N b
ut c
opie
s al
l tra
ffic
inco
min
g or
out
goin
g on
por
ts in
a
VL
AN
to
mon
itor
por
t.•
Tra
ffic
inte
rnal
ly r
oute
d to
VL
AN
not
mon
itor
ed (
does
not
com
e in
or
go o
ut a
V
LA
N p
ort)
.•
Mon
itor
por
t m
ight
be
in s
ame
or d
iffe
rent
VL
AN
.R
emot
e SP
AN
(R
SPA
N)
•Sa
me
idea
as
SPA
N b
ut c
opie
s tr
affic
to
a re
mot
e m
onit
or p
ort.
•Su
ppor
ts s
ourc
e po
rts
and
sour
ce V
LA
Ns.
•V
TP
prun
ing
can
bloc
k m
onit
ored
tra
ffic.
•M
onit
ored
tra
ffic
carr
ied
over
a s
ingl
e-pu
rpos
e V
LA
N.
L3Switch(config)# vlan 999
L3Switch(config-vlan)# remote-span
•T
he fo
llow
ing
exam
ple
confi
gure
s R
SPA
N to
cop
y tr
affic
from
por
t fas
teth
erne
t 2/2
(i
ncom
ing
and
outg
oing
) to
VL
AN
999
as
sess
ion
num
ber
8:L3Switch(config)# monitor session 8 source interface fastethernet 2/2 both
L3Switch(config)# monitor session 7 destination remote vlan 999
•V
iew
SPA
N s
etti
ngs:
L3Switch# show monitor session 7
Net
wor
k A
naly
sis
Mod
ule
(NA
M)
•M
odul
e fo
r C
atal
yst
6000
/650
0•
Acc
umul
ates
flow
info
rmat
ion
usin
g R
emot
e M
onit
orin
g (R
MO
N)
and
by
mon
itor
ing
VL
AN
s•
Use
s T
raffi
cDir
ecto
r or
any
RM
ON
app
licat
ion
to a
naly
ze d
ata
To c
onfig
ure
NA
M, a
ssig
n IP
set
ting
s an
d st
art
web
ser
ver:
L3Switch# sssseeeessssssssiiiioooonnnn ssssllllooootttt pppprrrroooocccceeeessssssssoooorrrr 1111
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp aaaaddddddddrrrreeeessssssss 11110000....0000....0000....2222 222255555555....222255555555....222255555555....0000
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp bbbbrrrrooooaaaaddddccccaaaasssstttt 11110000....0000....0000....222255555555
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp hhhhoooosssstttt MMMMyyyyNNNNAAAAMMMM
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp ggggaaaatttteeeewwwwaaaayyyy 11110000....0000....0000....1111
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp ddddoooommmmaaaaiiiinnnn sssstttteeeewwwwaaaarrrrtttt....hhhhiiiicccckkkkoooorrrryyyy....nnnncccc....uuuussss
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####iiiipppp nnnnaaaammmmeeeesssseeeerrrrvvvveeeerrrr 11110000....0000....0000....222255554444
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####ssssnnnnmmmmpppp llllooooccccaaaattttiiiioooonnnn AAAAtttt hhhhoooommmmeeee
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####ssssnnnnmmmmpppp ccccoooonnnnttttaaaacccctttt BBBBrrrreeeennnntttt SSSStttteeeewwwwaaaarrrrtttt
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####ssssnnnnmmmmpppp ccccoooommmmmmmmuuuunnnniiiittttyyyy ppppuuuubbbblllliiiicccc rrrroooo
rrrrooooooootttt@@@@llllooooccccaaaallllhhhhoooosssstttt####ssssnnnnmmmmpppp ccccoooommmmmmmmuuuunnnniiiittttyyyy pppprrrriiiivvvvaaaatttteeee rrrrwwww
•Id
enti
fy t
he s
et o
f in
form
atio
n yo
u w
ant
colle
cted
. Cho
ose
from
the
se c
olle
ctio
ns:
—ad
dres
smap
—ar
t (a
pplic
atio
n re
spon
se t
ime)
—et
hers
tat
—pr
iost
ats
—vl
anst
ats
root@localhost#autostart addressmap enable
•C
onfig
ure
the
NA
M c
olle
ctio
n po
rt 1
. NA
M m
ust
mon
itor
ses
sion
1.
L3Switch(config)# monitor session 1 destination interface gigabit 8/0
Vie
win
g N
AM
:sssshhhhoooowwww mmmmoooodddduuuulllleeee
sssshhhhoooowwww iiiinnnntttteeeerrrrffffaaaacccceeee ggggiiiiggggaaaabbbbiiiitttt 8888////1111
Secu
rity
in
th
e C
am
pu
s N
etw
ork
Secu
rin
g C
isco
Devic
es
Her
e ar
e so
me
basi
c se
curi
ty s
ugge
stio
ns f
or n
etw
ork
devi
ces:
•U
se p
assw
ords
tha
t ar
e no
t su
scep
tibl
e to
dic
tion
ary
atta
ck. A
dd n
umbe
rs o
r su
b-st
itut
e nu
mbe
rs a
nd s
ymbo
ls f
or le
tter
s, f
or e
xam
ple,
sub
stit
utin
g 0
for
o an
d us
ing
cisc
0.—
Con
sole
—A
UX
—E
nabl
e
—SN
MP
—V
TP
•L
imit
Tel
net
acce
ss u
sing
acc
ess
lists
.
0910_BCMSNssf.fm Page 477 Tuesday, September 9, 2003 8:20 AM
478 BCMSN Quick Reference Sheets•
Phys
ical
ly s
ecur
e ac
cess
to
the
devi
ce.
•U
se b
anne
rs t
hat
war
n ag
ains
t un
auth
oriz
ed a
cces
s.•
Rem
ove
unus
ed s
ervi
ces:
nnnnoooo sssseeeerrrrvvvviiiicccceeee ffffiiiinnnnggggeeeerrrr
nnnnoooo sssseeeerrrrvvvviiiicccceeee ccccoooonnnnffffiiiigggg
nnnnoooo sssseeeerrrrvvvviiiicccceeee ttttccccpppp----ssssmmmmaaaallllllll----sssseeeerrrrvvvviiiicccceeeessss
nnnnoooo sssseeeerrrrvvvviiiicccceeee uuuuddddpppp----ssssmmmmaaaallllllll sssseeeerrrrvvvviiiicccceeeessss
nnnnoooo ccccddddpppp eeeennnnaaaabbbblllleeee
nnnnoooo iiiipppp hhhhttttttttpppp
•Se
t up
and
mon
itor
sys
log.
•D
isab
le a
utom
atic
tru
nkin
g on
all
non-
trun
k po
rts
Aut
hent
icat
ion,
aut
hori
zati
on, a
nd a
ccou
ntin
g (A
AA
):•
Ver
ifies
ID
.•
Lim
its
priv
ilege
s.•
Log
s us
age
for
billi
ng o
r m
onit
orin
g.•
Con
figur
es a
uthe
ntic
atio
n:L3Switch(config)# aaa new-model
—Id
enti
fy a
uthe
ntic
atio
n m
etho
ds (
RA
DIU
S fir
st a
nd t
hen
the
loca
l use
rnam
e/pa
ssw
ord
data
base
in t
his
exam
ple)
:
L3Switch(config)# aaa authentication login default radius local
—A
pply
to
a lin
e:
L3Switch(config)# line vty 0 4
L3Switch(config-line)# login authentication default
•C
onfig
ure
auth
oriz
atio
n:—
Iden
tify
aut
hori
zati
on m
etho
ds (
RA
DIU
S in
thi
s ex
ampl
e):
L3Switch(config)#aaa authorization network default radius
—A
pply
to
inte
rfac
e:
L3Switch(config)# iiiinnnntttteeeerrrrffffaaaacccceeee ssss0000////1111
L3Switch(config-line)# pppppppppppp aaaauuuutttthhhhoooorrrriiiizzzzaaaattttiiiioooonnnn ddddeeeeffffaaaauuuulllltttt
•C
onfig
ure
acco
unti
ng:
—Id
enti
fy a
ccou
ntin
g m
etho
d:
L3Switch(config)# aaaaaaaaaaaa aaaaccccccccoooouuuunnnnttttiiiinnnngggg nnnneeeettttwwwwoooorrrrkkkk ddddeeeeffffaaaauuuulllltttt ssssttttaaaarrrrtttt----ssssttttoooopppp rrrraaaaddddiiiiuuuussss
—A
pply
to
inte
rfac
e:
L3Switch(config)# iiiinnnntttteeeerrrrffffaaaacccceeee ssss0000////1111
L3Switch(config-line)# pppppppppppp aaaaccccccccoooouuuunnnnttttiiiinnnngggg ddddeeeeffffaaaauuuulllltttt
Lim
itin
g M
AC
Access
•Po
rt s
ecur
ity
limit
s th
e nu
mbe
r of
MA
C a
ddre
sses
lear
ned
on a
por
t:L3Switch(config-if)# ssss wwww iiii tttt cccc hhhh pppp oooo rrrr tttt pppp oooo rrrr tttt ---- ssss eeee cccc uuuu rrrr iiii tttt yyyy mmmm aaaa xxxx 1111 vvvv iiii oooo llll aaaa tttt iiii oooo nnnn ssss hhhh uuuu tttt dddd oooo wwww nnnn
•80
2.1X
lim
its
netw
ork
acce
ss b
y au
then
tica
ting
at
data
link
bef
ore
allo
win
g ac
cess
:L3Switch(config)# aaaaaaaaaaaa nnnneeeewwww----mmmmooooddddeeeellll
L3Switch(config)# aaaaaaaaaaaa aaaauuuutttthhhheeeennnnttttiiiiccccaaaattttiiiioooonnnn ddddooootttt1111xxxx ddddeeeeffffaaaauuuulllltttt ggggrrrroooouuuupppp rrrraaaaddddiiiiuuuussss
L3Switch(config)# ddddooootttt1111xxxx ssssyyyysssstttteeeemmmm----aaaauuuutttthhhh----ccccoooonnnnttttrrrroooollll
L3Switch(config)# iiiinnnntttt ffffaaaasssstttteeeetttthhhh2222////1111
L3Switch(config-if)# ddddooootttt1111xxxx ppppoooorrrrtttt----ccccoooonnnnttttrrrroooollll aaaauuuuttttoooo
•V
iew
sec
urit
y se
ttin
gs:
L3Switch# sssshhhhoooowwww ppppoooorrrrtttt----sssseeeeccccuuuurrrriiiittttyyyy
Access L
ists
Cis
co s
wit
ches
sup
port
•T
radi
tion
al R
oute
r A
CL
(R
AC
L)
•Q
oS A
CL
•V
LA
N A
CL
(V
AC
L)
VL
AN
AC
L (
VA
CL
)•
App
lied
agai
nst
all V
LA
N t
raffi
c.•
Sim
ilar
to r
oute
-map
s:—
Stat
emen
ts c
onta
in m
atch
and
set
con
diti
ons
—St
atem
ents
num
bere
d fo
r or
deri
ng
•A
ctio
ns: P
erm
it, D
eny,
Red
irec
t•
The
fol
low
ing
is a
sam
ple
VA
CL
to
drop
tra
ffic
that
mat
ches
AC
L 1
01:
L3Switch(config)# vlan access-map Kaitlyn 5
L3Switch(config-access-map)# match ip address 101
L3Switch(config-access-map))# action drop
L3Switch# vlan filter Kaitlyn vlan_list 10
•V
iew
VA
CL
set
ting
s:sssshhhhoooowwww vvvvllllaaaannnn aaaacccccccceeeessssssss----mmmmaaaapppp KKKKaaaaiiiittttllllyyyynnnn
sssshhhhoooowwww vvvvllllaaaannnn ffffiiiilllltttteeeerrrr aaaacccccccceeeessssssss----mmmmaaaapppp KKKKaaaaiiiittttllllyyyynnnn
0910_BCMSNssf.fm Page 478 Tuesday, September 9, 2003 8:20 AM
Metro Ethernet Tunneling Options 479
Pri
vate
VLA
N (
PV
LA
N)
PVL
AN
s al
low
ser
vice
pro
vide
rs t
o is
olat
e cu
stom
ers
into
sep
arat
e m
ulti
acce
ss
dom
ains
. Usi
ng a
VL
AN
for
eac
h cu
stom
er is
n’t
scal
able
. PV
LA
Ns
isol
ate
a se
t of
po
rts
from
oth
er p
orts
in a
VL
AN
.Po
rt a
nd V
LA
N t
ypes
•C
omm
unit
y—C
omm
unic
ate
wit
h a
com
mun
ity,
plu
s pr
omis
cuou
s•
Isol
ated
—C
omm
unic
ate
just
wit
h pr
omis
cuou
s•
Prom
iscu
ous—
Com
mun
icat
e w
ith
all
To c
onfig
ure
VL
AN
, ent
er t
he f
ollo
win
g at
the
pro
mpt
:L3Switch(config)# vlan 777
L3Switch(config-vlan)# private-vlan isolated
Metr
o E
thern
et
Eth
erne
t as
a m
etro
polit
an a
rea
solu
tion
pro
vide
s at
trac
tive
fea
ture
s.Fo
r co
nsum
ers:
•L
ow c
ost
•H
igh
band
wid
th (
>1
G)
For
serv
ice
prov
ider
s:•
Prov
isio
ned
over
dar
k fib
er o
r ex
isti
ng s
ervi
ces
•Pr
ofita
ble
•Su
ppor
ts n
ew s
ervi
ces
Tra
nsp
are
nt
LA
N S
erv
ice
(T
LS
)•
Cus
tom
er s
wit
ches
see
MA
N a
s si
ngle
VL
AN
•Su
ppor
ts p
oint
-to-
poin
t an
d m
ulti
poin
t•
All
loca
tion
s m
ust
peer
. Som
e ro
utin
g pr
otoc
ols
have
tro
uble
pee
ring
mor
e th
an
40 d
evic
es.
•E
asy
to im
plem
ent.
•B
road
cast
and
mul
tica
sts
aren
’t co
ntro
lled,
QoS
is d
iffic
ult,
and
it’s
not
scal
able
.
Dir
ecte
d V
LA
N S
erv
ice
(D
VS
)•
Cus
tom
er s
witc
hes
see
MA
N a
s m
ultip
le V
LA
Ns,
eac
h go
ing
to a
spe
cific
nei
ghbo
r.•
Supp
orts
poi
nt-t
o-po
int
and
mul
tipo
int.
•V
LA
N id
enti
fies
dest
inat
ion,
sca
labl
e, S
Ps p
refe
r.•
Req
uire
s m
any
VL
AN
s.
Metr
o E
thern
et
Over
SO
NE
TM
etro
Eth
erne
t ove
r Sy
nchr
onou
s O
ptic
al N
etw
ork
(SO
NE
T) u
ses
exis
ting
ban
dwid
th
and
redu
ndan
cy o
f SO
NE
T t
o fa
cilit
ate
sim
ulat
ed E
ther
net
serv
ice.
•SO
NE
T h
as r
ing
stru
ctur
e.•
Met
ro E
ther
net
over
SO
NE
T e
mul
ates
hub
.•
SON
ET
gen
eral
ly a
vaila
ble,
qui
ck f
ailo
ver.
•C
usto
mer
buy
s ba
ndw
idth
in c
hunk
s of
51.
84 M
. (O
C-x
)
Metr
o E
thern
et
Over
DW
DM
Met
ro E
ther
net
over
den
se w
avel
engt
h di
visi
on m
ulti
plex
ing
(DW
DM
) us
es d
ark
fiber
or
wav
elen
gth.
•M
etro
Eth
erne
t ov
er S
ON
ET
em
ulat
es h
ub.
•G
igab
it p
lus
band
wid
th, a
nd e
asy
to c
onfig
ure.
•B
uilt
on
dark
fibe
r or
wav
elen
gth
(not
gen
eral
ly a
vaila
ble)
.
Metr
o E
thern
et
Over
CW
DM
Met
ro E
ther
net
over
Cou
rse
Wav
e-D
ivis
ion
Mul
tipl
exin
g (C
WD
M)
uses
dar
k fib
er o
r w
avel
engt
h.•
Las
t m
ile t
echn
olog
y•
Doe
sn’t
use
band
wid
th a
s ef
ficie
ntly
•L
ast
mile
tec
hnol
ogy
•C
heap
(co
mpa
rati
vely
)
Metr
o E
thern
et
Tu
nn
elin
g O
pti
on
sT
raffi
c cr
ossi
ng t
he s
ervi
ce p
rovi
der
can
be e
ncap
sula
ted
to p
rese
rve
priv
ate
VL
AN
ta
gs a
cros
s th
e ba
ckbo
ne.
No
Tu
nn
elin
g•
Cus
tom
er t
raffi
c is
olat
ed in
one
or
mor
e V
LA
Ns
in s
hare
d de
finit
ion
set.
•E
asy
to im
plem
ent.
•D
oesn
’t sc
ale—
Serv
ice
prov
ider
run
s ou
t of
VL
AN
s!•
Use
d to
bui
ld lo
w-c
ost
MA
N s
ervi
ces.
0910_BCMSNssf.fm Page 479 Tuesday, September 9, 2003 8:20 AM
480 BCMSN Quick Reference Sheets802.1
Q-i
n-Q
•Tw
o do
t1q
tags
ass
ocia
ted
wit
h fr
ame—
One
for
ent
erpr
ise
and
one
for
serv
ice
prov
ider
.•
Als
o ca
lled
tag
stac
king
.•
SP r
eads
the
ir t
ag, r
emov
es b
efor
e pa
ssin
g ba
ck.
•Is
olat
es e
nter
pris
es f
rom
eac
h ot
her.
•E
nter
pris
e se
es Q
-in-
Q a
s tr
unk
serv
ice
betw
een
site
s.•
Span
ning
tre
e us
ed t
o pr
even
t lo
ops.
•ST
P ca
n ca
use
issu
es w
ith
back
bone
.•
Red
unda
nt li
nks
supp
orte
d w
ith
Eth
erC
hann
el.
•E
asy
to s
et u
p an
d su
ppor
t.
MP
LS
Secre
t D
eco
der
Rin
gB
efor
e w
e di
scus
s M
etro
Eth
erne
t ov
er M
PLS,
her
e’s
a re
min
der
of im
port
ant
MPL
S ac
rony
ms
is a
ppro
pria
te:
•L
abel
Sw
itch
Rou
ter
(LSR
)—D
evic
e th
at f
orw
ards
tra
ffic
insi
de a
n M
PLS
dom
ain.
•L
abel
Dis
trib
utio
n Pr
otoc
ol (
LD
P)—
Prot
ocol
tha
t sy
nchr
oniz
es la
bel d
efini
tion
s be
twee
n L
SR.
•L
abel
Sw
itch
Con
trol
ler
(LSC
)—M
PLS
rout
er t
hat
wor
ks w
ith
AT
M s
wit
ch t
o fo
rwar
d M
PLS
traf
fic.
•L
abel
Edg
e R
oute
r (L
ER
)—D
evic
e th
at s
its
betw
een
Eth
erne
t an
d M
PLS.
Map
s E
ther
net
traf
fic t
o M
PLS
labe
ls.
Eo
MP
LS
•V
LA
N m
appe
d to
MPL
S tu
nnel
.•
Poin
t-to
-poi
nt o
nly.
•R
equi
res
eith
er f
ull m
esh,
or
traf
fic t
o ex
it M
PLS
to a
sw
itch
and
be
pass
ed b
ack
to M
PLS
(a h
airp
in t
urn)
.•
Ver
y sc
alab
le.
•Su
ppor
ts T
rans
port
Lay
er S
ecur
ity
(TL
S) f
unct
iona
lity—
mak
es d
ispa
rate
net
-w
orks
app
ear
as o
ne L
AN
.•
Use
s a
tunn
el la
bel a
nd a
vir
tual
cir
cuit
labe
l app
lied
by L
ER
.•
Ingr
ess
LE
R u
ses
Forw
ardi
ng E
quiv
alen
ce C
lass
(FE
C)
to m
ap t
raffi
c to
Lab
el
Swit
ch P
ath.
•L
SRs
alon
g L
SP ju
st u
se t
unne
l lab
el t
o di
rect
tra
ffic.
•V
irtu
al c
ircu
it la
bel u
sed
by L
ER
to
dem
ux.
•C
oS m
appe
d to
3 b
it E
XP
field
in la
bel.
Eo
MP
LS
Po
int-
to-M
ult
ipo
int
•Pr
ovid
es f
eatu
res
of E
oMPL
S pl
us m
ulti
poin
t co
nfigu
rati
ons.
•Se
rvic
e ac
ts li
ke a
n E
ther
net
swit
ch.
•E
ffici
entl
y ha
ndle
s tr
affic
(so
lves
hai
rpin
tur
n).
DA
SA
ET
YP
ED
ata
802.
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unk
Por
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802.
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0910_BCMSNssf.fm Page 480 Tuesday, September 9, 2003 8:20 AM
0910_BCMSNssf.fm Page 481 Tuesday, September 9, 2003 8:20 AM