qos in pppoe quality of service in the point-to-point protocol over ethernet master’s thesis...
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QoS in PPPoE
Quality of Service in the Point-to-Point Protocol over Ethernet
Master’s Thesis
Patrik LahtiKTH, Telia Research AB
25/10/2000 QoS in PPPoE 2
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 3
Quality of Service
• Enhance the network with the intelligence to treat traffic according to application requirements.– Delay
– Delay variation
– Loss
– Others...
• IP– Differentiated Services
– Integrated Services
• Ethernet– Priorities (802.1p)
– Subnet Bandwidth Manager
25/10/2000 QoS in PPPoE 4
Point-to-Point Protocol over Ethernet
• Purpose– To set up Client to Access Concentrator relationship
– Encapsulate PPP, and multiplex multiple PPPoE sessions
• Operation– Simple Active discovery
– Session
25/10/2000 QoS in PPPoE 5
PPP/PPPoE
t
Mulitcast PADI, w Service-Name
Unicast PADR, w Service-Name
Unicast PADO, w Service-Name(s)& AC-Name
Unicast PADS, w Service-Name& Session ID
Unicast PADO, w Service-Name(s)& AC-Name *)
*) There may be multiple ACs answering with a PADO**) May be sent by either side
PPP session Stage
Unicast PADT, w Session ID **)
Client AC
LCP
Auth
IPCP
IP data
ACClient
25/10/2000 QoS in PPPoE 6
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 7
Background& Model
• CPN
• VLAN
• IP Access Node
• New Services => QoS
• NSP selection
• Protocols ATM
STB
PC
IPT
Ethernet Sw
Ethernet Sw
Ethernet Sw
IP-accessNode
AAA
IP Network
100Mbps Ethernet
10Mbps Ethernet
1Gbps Ethernet
ADSLmod.
STB
PC
IPT10Mbps Ethernet
ADSL
DS
LA
M
Ethernet
PPPoE
Physical
PPP
IP
Ethernet
Physical
Ethernet
Physical
Ethernet
Physical
Ethernet
Physical
Ethernet
PPPoE
Physical
PPP
IP
Sw Sw
?
IP
CustomerEquipment
EthernetSwitch
EthernetSwitch
IP-accessNode
25/10/2000 QoS in PPPoE 8
Why PPP/PPPoE?
+ NSP selection
+ IP address allocation
+ Reuse of Legacy Equipment
+ Unified Model (Bridged ADSL)
+ Familiar to users
+ Per user access control and billing
- Overhead and Connection delay(?)
- Software update for Clients
- QoS issues unresolved (?)
25/10/2000 QoS in PPPoE 9
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 10
Problem Definition
• With what methods can QoS be support be introduced in PPPoE?
• Can services with different QoS requirements be multiplexed in one PPPoE session?
• Does PPP/PPPoE cope with loss, delay, reordering, and duplication?
• How is performance affected by PPP/PPPoE?• What issues have to be addressed in the IP access?
25/10/2000 QoS in PPPoE 11
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 12
QoS in the PPPoE-based Broadband IP Access.
• IP Differentiated Services
– Guaranteed Service
– Low Delay
– Low Loss
– Best Effort
• Ethernet User Priorities, 802.1p– 7 Traffic types: NC, Voice, Video, Controlled Load, Excellent
Effort, BE, Background
• PPP/PPPoE?
25/10/2000 QoS in PPPoE 13
QoS
• PPPoE
– Service Name Tag, request certain DS or Service.• Allows CAC
• Integrate with/similar to SBM?
• One session/service or DSCP
• PPP
– DiffServ SLA negotiation• Allows CAC
– Fragmentation (slow link)
25/10/2000 QoS in PPPoE 14
QoS• QoS scope
25/10/2000 QoS in PPPoE 15
QoS
• Mapping DS to 802.1p– Static
– Hint in DS field
– SBM
• Recommendation:– Static
– Proposed mapping
– No change to PPP/PPPoE
Ethernet Traffic Class Service Class
7 Network Control Guaranteed Service
6 Voice Low Delay (-jitter)
5 Video
4 Controlled Load Low Loss
3 Excellent Effort
0 Best Effort Best Effort
1 Background
25/10/2000 QoS in PPPoE 16
Multiplexing QoS
• Alternatives– One PPPoE session/NSP
– One PPPoE session/DS class
– One PPP session/DS class
25/10/2000 QoS in PPPoE 17
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 18
Stability and Performance of PPPoE
• Stability– Loss– Delay– Reorder– Duplication
• Performance– Connection delay– Maximum throughput
25/10/2000 QoS in PPPoE 19
Stability
• Lab
25/10/2000 QoS in PPPoE 20
Stability
• Result– PADS, PAP Authentication sensitive to loss
– Old LCP, IPCP packet Ids not ignored
– TCP segment size smaller than necessary
– Termination and Link maintenance
– Delays < 3s
25/10/2000 QoS in PPPoE 21
Performance
• Lab– 10Mbps FD
– 1Mbps HD
– 9 Mbps Load w/wo VLAN
– Connection Delay
25/10/2000 QoS in PPPoE 22
Performance
• Results– No significant
difference
– Except on1Mbps HD
– ConnectionDelay ~7s
– Can be optimised to ~1s
0
100
200
300
400
500
600
700
800
900
1000
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65
Time [s]
Th
rou
gh
pu
t [k
bp
s]
Serie1
Throughput [kbps] (variance) IP PPPoE Difference
10Mbps Full-Duplex 7955 (208) 7520 (242) -5.5%
1Mbps Bottleneck 853 (60.0) 767 (170) -10.1%
9 Mbps Load 4760 (12.3) 4644 (14.4) -2.4%
9 Mbps Load VLAN sep. 4759 (18.3) 4646 (16.1) -2.4%
25/10/2000 QoS in PPPoE 23
Outline
• Introduction– Quality of Service
– Point-to-Point Protocol over Ethernet
• Background and Model
• Problem Definition
• QoS in the PPPoE-based Broadband IP Access.
• Stability and Performance of PPPoE
• Summary, Questions & Credits
25/10/2000 QoS in PPPoE 24
Summary
• QoS can be incorporated in the PPPoE architecture without changes to protocol standards.
• PPPoE implementation to set Ethernet user priorities according to IP DS.
• Simple multiplexing should be used, one PPPoE session/NSP.
• PPP/PPPoE is reasonably stable and performs well. Some issues to be further investigated and improved.
25/10/2000 QoS in PPPoE 25
Opposition
• ...
25/10/2000 QoS in PPPoE 26
Questions
• ?
25/10/2000 QoS in PPPoE 27
Thank you!
• Tack till Fredrik Roos, Stefan Sandell
• Alla på Bredbandsnät, Telia Research AB
• Tack till Björn Pehrson och Mikael Lind
• Tack till alla som kom.
25/10/2000 QoS in PPPoE 28
Information
• http://www.e.kth.se/~e95_pla/exjobb
• Still have my opposition to do.
• I am currently working at Nortel Networks’ Routing Architecture Lab:patrik.lahti@nortelnetworks.com
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