m-hbh efficient mobility management in multicast

M-HBHM-HBHEfficient Mobility Management in MulticastEfficient Mobility Management in Multicast

Rolland Vida, Luis Costa, Serge FdidaRolland Vida, Luis Costa, Serge FdidaLaboratoire d’Informatique de Paris 6 – LIP6 Laboratoire d’Informatique de Paris 6 – LIP6

Université Pierre et Marie Curie, ParisUniversité Pierre et Marie Curie, Paris

NGC ‘02, October 23-25, Boston, MANGC ‘02, October 23-25, Boston, MA

NGC ’02, Boston, MANGC ’02, Boston, MA 22

OutlineOutline

The mobility problem in a multicast group Traditional solutions

Bi-directional tunneling Remote subscription

The original HBH protocol Mobility handling in M-HBH Performance analysis Conclusion


The problemThe problem

More and more emerging mobile devices Mobility handling became an important service

requirement The multicast service:

a multicast group, identified by a multicast address G

a source S that sends data to G a receiver r that listens to packets sent to G

How to assure multicast data delivery if … the source S is mobile

or the receiver r is mobile


Traditional solutions (1)Traditional solutions (1)

Proposed by Mobile IP [Perkins, RFC 3220] Bi-directional tunneling (BT)

tunnel between the home and the foreign location of the MN

Source mobility: data is tunneled to the home network, and then

retransmitted on the old tree Receiver mobility: data is delivered on the old

tree, and then tunneled to the MN

Drawbacks: triangular routing encapsulation/decapsulation of data tunnel convergence (receiver mobility)


ExampleExample

R1

R5

R4

R2

R3

S

r4r3

r2

r1

S’ HA


Traditional solutions (2)Traditional solutions (2)

Remote subscription (RS) reconfiguration of the multicast tree according

to the new location of the MN Source mobility: receivers redirect their Join

messages towards the new location of the source Receiver mobility: the MN joins the tree from

its new location Drawbacks:

Source mobility: • the entire tree must be reconstructed• reconstruction is costly, not efficient for a highly

mobile source Receiver Mobility

• cost is lower, only a branch has to be added


ExampleExample

R1

R5

R4

R2

R3

S

r4r3

r2

r1

S’

R6

R7


ExampleExample

R1

R5

R4

R2

R3

S

r4r3

r2

r1

S’

R6

R7

R1

S


Hybrid solutionsHybrid solutions

Switch between the two techniques, based on specific criteria

Mobile Multicast Protocol (MoM) [Harrison et al., Mobicom ’97]

Range-Based MoM [Lin et al., Infocom ’00]

Hierarchical Multicast Architecture [Wang et al., ACM Mobile Networks and

Applications, 2001]


HBH multicast HBH multicast

In traditional multicast, the group is a single unit, identified by the multicast address

Mobility of an individual member is hard to handle Keep the unit (tree) + tunnel Reconstruct the unit (tree)

HBH – Hop-By-Hop Multicast Routing [Costa et al., Sigcomm ’01] Uses a recursive unicast addressing scheme to

provide multicast Data is not sent to the group, but to the next

branching node Nodes are handled as individuals, not as a

group


Data delivery in HBHData delivery in HBH

H1

H5

H4

H2

H3

S

r4r3

r2

r1

r4r3S

H4S H3

S H2

H2S

r2

r2r1S

S

MFT

MFT

MFTMFT

MCT

MCT

H1

H2

Relay Node

Branching Node

MFT – Multicast Forwarding Table

MCT – Multicast Control Table


The M-HBH protocol The M-HBH protocol

In HBH multicast, nodes are treated as individuals, not as a group

Mobility is easier to handle Mobile Hop-By-Hop Multicast Routing

Protocol Extension of HBH Handles both source and receiver mobility Mobile Node

Multicast connectivity – M-HBHUnicast connectivity – Mobile IP


Source mobility with M-HBHSource mobility with M-HBH

H1

H5

H4

H2

H3

S

r4r3

r2

r1

r4r3

H4S/S H3

H2

H2

r2

r2r1

MFT

MFT

MFTMFT

MCT

MCT

S’

U1

U2

S/S

S/S

S/S

S/S

S/SH2

MFTS/S’

S/S’

S/S’S/S’

S/S’

U Unicast Router


Receiver mobility with M-HBHReceiver mobility with M-HBH

H1 H2

U

S

r3

r2’r2

r1

r3H1S

S

MFT

MCT

H3

H4r2

SMCT

r2

SMFT

r1 r2r2/r2’ SMCT

r3

Join (r2/r2’)

Multicast Data

HA

HA Home Agent

r2


Advantages of M-HBHAdvantages of M-HBH

Reduces triangular routingBetter delivery path

No encapsulation, no tunneling Transparent handling of mobility Preserves the advantages of HBH

Passes through unicast-only cloudsTakes into account asymmetric routes,

data is forwarded on direct shortest path

Limits tree reconstruction …


The M-HBH tradeoffThe M-HBH tradeoff

M-HBH represents a trade-off between:Shortest path deliveryTree reconstruction

M-HBH shortcuts routing triangles, but…Passing through the first (or the last)

branching node does not assure shortest path delivery

Periodical tree reconfiguration can be considered

Reconfiguration frequency is limited


Routing triangleRouting triangle

SS’

F

xS

yS

zS

S

L

z r

y r

x r

F First branching node

L Last branching node


Performance analysisPerformance analysis

Mathematical modelsK-ary treesSelf-similar trees

SimulationRealistic Internet-like generated

topology


Simulation results (multicast Simulation results (multicast tree shape)tree shape) Average length of Xs vs. Xr


Simulation results (source Simulation results (source mobility)mobility) A) Average delivery delay M-HBH vs. BT vs. RS B) Relative gains in average delivery delay, for M-

HBH over BT, proportional to the average length of Xs


Simulation results (receiver Simulation results (receiver mobility)mobility) A) Average delivery delay M-HBH vs. BT vs. RS B) Relative gains in average delivery delay, for M-

HBH over BT, proportional to the average length of Xr


ConclusionConclusion

Traditional solutions have drawbacks: Triangular routing, encapsulation (BT) Frequent tree reconstruction (RS)

M-HBH uses a recursive unicast addressing scheme Reduces routing triangles eliminates tunneling limits tree reconstruction

Simple, transparent, incrementally deployable Simulations show important performance gains Further details and analysis:

hhtp://www-rp.lip6.fr/~vida/mhbh_techrep.pdf


Questions?


Mobile multicast sourceMobile multicast source

Shared Multicast Tree (CBT, PIM-SM) S sends data in unicast to the core (RP) data is retransmitted on the shared tree if S moves in a new network, it still can send

unicast packets to the core (RP). Data is delivered to receivers.

Source-Specific Multicast Tree (PIM-SSM) the multicast tree is rooted in the home

network of S S moves in a new network and obtains a new

address (S’): Multicast packets sent by S’ are dropped if …

• no multicast router in the visited network• no multicast routing state in the router

m-hbh efficient mobility management in multicast

Documents

multicast tree

hbh multicast

traditional multicast

multicast addressmobility

multicast data delivery

group mobility

multicast routing costa

mnsource mobility