QoS-based Multicast Routing Mechanism

1. QoS-based Multicast Routing Mechanism 숙명여대 컴퓨터과학과 최종원(임유진) choejn@cc.sookmyung.ac.kr yujin@cs.sookmyung.ac.kr

2. Contents • What is Quality-of-Service? • QoS-based Routing Overview • Issues • Multicast QoSR • Conclusion SIG Router Korea

3. What is Quality-of-Service?

4. Definition • Quality • the process of delivering data in a reliable manner or even somehow in a manner better than normal. • Service • something offered to the end-users of any network • Service Guarantees • not only no loss occur, but also the performance of the network is consistent and predictable. SIG Router Korea

5. QoS-parameter • Performance-oriented • end-to-end delay, bit rate, ... • Format-oriented • Synchronization-oriented • Cost-oriented • User-oriented SIG Router Korea

6. QoS Issues • User Interface • Encoding mechanism • Operating Systems • Communication Protocol • lower layer protocols • network and transport protocols • application layer protocol SIG Router Korea

7. QoS-based Routing

8. Background • Routing in today’s Internet • focus on connectivity • support one type of datagram service, “best-effort” • optimizing for a single metric • QoS-based Routing • based on some knowledge of resource availability in the network as well as the QoS requirement of flows SIG Router Korea

9. Integrated Service • Best Effort Service • Controlled-Load Service • Guaranteed Service SIG Router Korea

10. Issues • How do routers determine the QoS capability of each outgoing link? • What is the granularity of routing decision? • What routing metrics are used and how are QoS-accommodating path computed? • For Unicast & Multicast flows SIG Router Korea

11. Issues (Cont.) • What are the performance objectives? • What are the administrative control issues? • What factors affect the routing overheads? • How is scalability achieved? SIG Router Korea

12. IETF QoSR WG

13. Charter • Define a framework and techniques for QoS Routing in the Internet • focus on how to select and maintain packet forwarding paths capable of meeting specific service class objectives. • Mailing lists • qosr@newbridge.com • RFC 2386 • A Framework for QoS-based Routing in the Internet SIG Router Korea

14. IETF Meetings • 36th, 37th IETF (1996’) • QoSR BOF • 38th, 39th, 40th IETF (1997’) • QoSR meetings • 41th, 42th, 43th IETF (1998’) • No meeting SIG Router Korea

15. QoS-based Multicast Routing

16. Framework • sender traffic adv are multicast over best-effort tree • each receiver-side router independently computes a QoS-accommodating path from source, based on the receiver reservation • routing processing unicast reserve msg from receivers aggregate resource reservations from multiple receivers SIG Router Korea

17. Metrics • Tree Cost • end-to-end delay • bandwidth • delay variation SIG Router Korea

18. Multiple Metrics • The complexity is primarily determined by the composition rules of the metrics. • Additive metric • Multiplicative metric • Concave metric SIG Router Korea

19. Constrained Steiner Tree Problem Given a graph G=(V,E) with a link-cost function cost(e), a link-delay function delay(e), a source s, a set of destinations D={d1, …, dm}  V-{s}, and a QoS constraints i for each di D, construct a CMT spanning D  {s}, such that minimize eTcost(e), subject to ePT(s,di)delay(e)  i diD SIG Router Korea

20. KPP algorithm • Based on KMB algorithm • Combined function (cost + delay) Cm=W(u,v) / D-DP(u)-D’(u,v) • Centralized version vs. Distributed version SIG Router Korea

21. Sun’s algorithm • Centralized version • based on Dijkstra’s algorithm • firstly constructing a constrained low cost tree, T1 • then computing the shortest delay path tree, T2 • for nodes which are not in the constructed constrained tree. • Combining T1 and T2. SIG Router Korea

22. Sun’s algorithm (cont’) • Distributed Delay-constrained Dynamic multicast routing algorithm (DCDMR) • FAST mode • based on DCR (Delay-Constrained unicast routing algorithm) • SLOW mode • based on Greedy heuristic SIG Router Korea

23. A A A (20,2) (20,2) (20,2) (30,1) (30,1) B (30,1) B B C C (10,1) C (10,1) (10,1) (10,1) (10,1) (10,1) D D (30,1) D (30,1) (30,1) (10,2) (10,2) (10,2) E E E Sun’s algorithm (cont’) • Delay-Constrained unicast routing algorithm (cost, delay) =5 SIG Router Korea

24. F{4} F{4} 3,2.5 A A E{4} G{5} E{4} G{5} S S 2,2 10,1.5 B B 14, 1.5 D D C{5.5} C{5.5} Garcia • Bounded Shortest Multicast algorithm (BSMA) • Centralized version SIG Router Korea

25. Garcia (Cont.) • Distributed Constrained Multicast algorithm (DCMA) • starts with minimum delay tree • delay-bounded tree Rearrangement • iterative and periodic computation • to minimize the cost while satisfying the delay constraints • adapts to the network topology and link quality changes and group dynamics SIG Router Korea

26. DVMA algorithm • Delay Variation Multicast algorithm • considered metric • source-destination delay lPT(s,v)D(l), vM • Interdestination delay variation |lPT(s,v)D(l) - lPT(s,u)D(l)|, v,uM • firstly constructing minimum delay tree • based on Dijkstra’s algorithm • pick the node with the longest path in the tree SIG Router Korea

27. QOSPF Zhang • Extension of OSPF / MOSPF • 2 additional advertisement • RES-LSA • RRA SIG Router Korea

28. Domain B Domain B Domain B Domain A Domain A Domain A QoSMIC • One-to-Many Join (based on YAM) SIG Router Korea

29. QoSMIC (Cont.) • Joining a group • Local Search • similar to YAM • Multicast Tree Search • new concept of “Manager” node • causes some of the intree nodes to propose themselves as Candidate routers • to reduce the scope of the Local Search SIG Router Korea

30. source manager Local Search new QoSMIC (Cont.) • Search procedure SIG Router Korea

31. QoS extension to CBT • Extension to the CBT protocol to maintain a multicast tree with user-specified QoS properties • Metric • Additive QoS • Multiplicative QoS • Concave QoS SIG Router Korea

32. QoS extension to CBT (Cont.) • Eligibility Test • to verify whether or not a new member can join a tree at adequate QoS • while not violating the QoS received by on-tree members SIG Router Korea

33. Core Join_Req msg. U Join_Req msg. V D_{Max}(*,u) QoS extension to CBT (Cont.) • Additive QoS (end-to-end delay) SIG Router Korea

34. Conclusions • In the last few years, QoS-based routing and Multicast routing have attracted a lot of attention from NC • Inter-Domain QoS-based Routing is also an important issue • The issues are only outlined! SIG Router Korea

35. References • E.Crawley, R.Nair, B.Rajagopalan, and H.Sandick. “A Framework for QoS-based Routing in the Internet”. RFC 2386, Aug 1998. • R.Guerin, S.Kamat, A.Orda, T.Przygienda, D.Williams. “ QoS Routing Mechanism and OSPF Extensions”. Internet-Draft. March 1997. • H.F.Salama, D.S.Reeves, Y.Viniotis. “A Distributed Algorithm for Delay-Constrained Unicast Routing”. IEEE INFOCOM. April 1997. • N.S.V.Rao, S.G.Batsell. “QoS Routing Via Multiple Paths Using Bandwidth Reservation”. IEEE INFOCOM. March 1998. • V.P.Kompella, J.C.Pasuale, G.C.Polyzos. “Multicasting For Multimedia Applications”. IEEE Trans. on networking. 1993. • M.Parsa, J.J.Garcia. “A Source-based Algorithm for Delay-Constrained Minimum-Cost Multicasting”. IEEE INFOCOM. 1995. • M.Faloutsos, A.Banerjea, R.Pankaj. “QoSMIC: Quality of Service sensitive Multicast Internet protoCol”. ACM SIGCOMM. Sep 1998. SIG Router Korea