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A Fast Delay-Constrained Multicast Routing Algorithm

Baoxian Zhang; Krunz, M.M.; Changjia Chen

Communications, 2001. ICC 2001. IEEE International Conference on , Volume: 9 , 2001

Page(s): 2676 -2680

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Outline

Motivation,model and problem SDCR heuristic for unicast DCMA heuristic for multicast Simulation results Conclusion

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Motivation

Objective

– Construct a delay-constrained multicast tree with lower complexity

– DCMA heuristic : Earlier research

– BSMA heuristic :– KPP heuristic :– CKMB heuristic :

)log||( 3 VVkO

)||( 3VO )||( 2VmO

|)|log( VmmO

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Model and Problem

Given – A network graph : G(V,E)– Each link has

• Delay value D(e)• Link cost C(e)

– Source node s– Destination set – Delay constraint

Ee

sVS

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Model and Problem

Finda tree T rooted at s and span all nodes satisfying – – is minimum

)( GT

),()(

vsPeeD

TeeC )(

Sv

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Routing information

Source routing strategy– Source maintain full information– OSPF is used

Two vectors – Delay vector– Cost vector– Each has |V|-1 entries for sVv j

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Routing information (cont.)

Entry for in delay vector– Destination ID– End to end delay of least delay path– Predecessor of on

Entry for in cost vector – Destination ID– End to end delay of least cost path – Predecessor of on

jv

),( jld vsP

jv ),( jld vsP

jv

),( jlc vsP

),( jlc vsPjv

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Outline

Motivation,model and problem SDCR heuristic for unicast DCMA heuristic for multicast Simulation results Conclusion

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Source-based Delay Constrained Routing (SDCR)

Objective– Find a delay-constrained least cost path

between source and a destination Idea

– Start from d – Backward to s along until

•

– Then continues along until reach s

),( dsPld

)),(()),(( dvPDvsPD ldlc

),( vsPlc

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Example of SDCR Heuristic

s

D

F

E

Destination : F

Each link has {cost,delay} pair

Delay constraint : 6

(1,3) (1,4)

(5,1) (3,1)

(3,1)

s

D

E

F s

D

F

ERelay node

(a) (b)

(a) SDCR

(b) LD path

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SDCR Heuristic (cont.)

Complexity is O(|V|) Lemma

– SDCR returns a loop-free path Idea

– can not contain any node on ,besides relay node u

),( usPlc ),( duPld

s u v d

LD path

LC path

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Outline

Motivation,model and problem SDCR heuristic for unicast DCMA heuristic for multicast Simulation results Conclusion

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Delay Constrained Multicast Algorithm (DCMA)

Based on SDCR algorithm Earlier research

– Union of all delay-constrained unicast paths– Loop will happen

Loop phenomenon

s v

d2

d1

w

relay node of d1

u

relay node of d2LD path

LC path

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Loop free DCMA Heuristic

Idea – First phase

• Proceed along path• Until a node v

– Marked or satisfy

– Second phase • Connect each v to s along• Until

– Reach s or a node on existing tree

),( dsPld

)),(()),(( dvPDvsPD ldlc

),( vsPlc

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First Phase of DCMA Heuristic

while S is not empty active_node d remove d while ON[active_node]=0 if ON[active_node] ld_lhop active_node ld_lhop else Q[d]=active_node break

)),_(())_,(( dnodeactivePDnodeactivesPD ldlc

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Second Phase of DCMA Heuristic

for i=1 to |S| if Q[i] NULL active_node = Q[i] while ON[active_node]=0 ON[active_node] lc_lhop active_node lc_lhop

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Example of DCMA Heuristic

s

d1

d2v

uS = {d1,d2}Q[d1]=Q[d2]=u LD path LC path

relay node=Q[d1]

s

u

v

d1

d2

Final tree

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DCMA Heuristic (cont.)

Lemma– The tree constructed by DCMA is always

loop-free Possible case for loop

– Source s,destination {x,y,z}

s

u

q

z

vx

y

s

u

q

z

v w

x

y

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Outline

Motivation,model and problem SDCR heuristic for unicast DCMA heuristic for multicast Simulation results Conclusion

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Simulation

Parameters – Link capacity with 155 Mbps– Cost

• Total reserved bandwidth

– Traffic• Uniform distributed 10M and 120Mbps

Performance evaluation• Cost of LD, DCMA, CDKS heuristics with

respect to CKMB

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Simulation Results

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Outline

Motivation,model and problem SDCR heuristic for unicast DCMA heuristic for multicast Simulation results Conclusion

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Conclusion

Complexity– SDCR : O(|V|)– DCMA : O(mlogm+|V|)

DCMA heuristic– achieve good performance and complexity