1 A Fast Delay-Constrained Multicast Routing Algorithm Baoxian Zhang; Krunz, M.M.; Changjia Chen Communications, ICC IEEE International Conference on, Volume: 9, 2001 Page(s):

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

3 Motivation Objective –Construct a delay-constrained multicast tree with lower complexity –DCMA heuristic : Earlier research –BSMA heuristic : –KPP heuristic : –CKMB heuristic :

4 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

5 Model and Problem Find a tree T rooted at s and span all nodes satisfying – – is minimum

6 Routing information Source routing strategy –Source maintain full information –OSPF is used Two vectors –Delay vector –Cost vector –Each has |V|-1 entries for

7 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

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

9 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

10 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) s D E Fs D F E Relay node (a)(b) (a)SDCR (b)LD path

11 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 suvd LD path LC path

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

13 Delay Constrained Multicast Algorithm (DCMA) Based on SDCR algorithm Earlier research –Union of all delay-constrained unicast paths –Loop will happen Loop phenomenon sv d2 d1 w relay node of d1 u relay node of d2 LD path LC path

14 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

15 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

16 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

17 Example of DCMA Heuristic s d1 d2v u S = {d1,d2} Q[d1]=Q[d2]=u LD path LC path relay node=Q[d1] s u v d1 d2 Final tree

18 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 v x y s u q z vw x y

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

20 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

21 Simulation Results

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

23 Conclusion Complexity –SDCR : O(|V|) –DCMA : O(mlogm+|V|) DCMA heuristic –achieve good performance and complexity