1 / 26

Traffic Engineering and Routing

Traffic Engineering and Routing . Hansen Bow. Topics. Traffic Engineering with MPLS Issues Concerning Voice over IP Features of Netscope QoS Routing for High-Speed Networks QoS Routing for Multimedia. Traffic Engineering with MPLS: Methods. MPLS – multiprotocol label switching

wayland
Télécharger la présentation

Traffic Engineering and Routing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Traffic Engineering and Routing Hansen Bow

  2. Topics • Traffic Engineering with MPLS • Issues Concerning Voice over IP • Features of Netscope • QoS Routing for High-Speed Networks • QoS Routing for Multimedia

  3. Traffic Engineering with MPLS:Methods • MPLS – multiprotocol label switching • Constraint-based routing • Enhanced link state IGP

  4. MPLS-multiprotocol label switching • forwarding scheme • at ingress of MPLS network, IP packets are classified, tagged, and routed • at next router, tag is used to determine destination • before leaving, tag is removed

  5. Constraint-Based Routing • computes bounded routes • reservable bandwidth of a link is an approximation • can be done online or offline

  6. Enhanced Link State IGP (interior gateway protocol) • distribute link information • flood network to obtain information

  7. Deploying MPLS System (GlobeCenter) • Statistics Collection • Deploy LSP (label-switched path) with bandwidth constraint • Periodic update of LSP Bandwidth • Offline Constraint-Based Routing

  8. Voice over IP Issues • modify capacity management and routing methods in IP to support IP telephony • delay less than 300ms • loss rate <1% • First Model: RSVP • Second Model: voice service uses Virtual Private Network

  9. RSVP Routing • Shortest Path First • Shortest Available Path First • Widest Available Path First

  10. Virtual Private Networks • interconnects telephony switches • Direct Path Only • Success to the Top • State-Dependent Routing • Approximate State-Dependent Routing

  11. Direct and Alternate Routing Policies

  12. Differently Routed Calls with Trunk Reservation

  13. Routing Policies with Integrated Services Model • not much difference between SPF, SAPF, WAPF • fewer blocked calls for a given network capacity because of better sharing of network capacity

  14. Features of Netscope • traffic measurement and network modeling • provide global views of configuration and useage data

  15. Utility of Netscope • realizing customer SLAs • tuning parameters of network components • unite configuration • experiment with possible solutions to variable complex traffic

  16. Data • Network components • Modeling Traffic • Routing • multiple shortest paths

  17. Visualization • Objects • Statistics • Traffic and Links • Changing Routes

  18. QoS Routing Issues for High Speed Networks • Goals • satisfy QoS requirements for admitted connection • global efficiency • Classes • Source routing • Distributed routing • Hierarchical routing

  19. Routing • Collection of State Information • local and global state • aggregated global state

  20. Routing • Finding Feasible Path • Unicast • link optimization • link constrained • path optimization • path constrained • Dijkstra’s algorithm • http://www.cs.uwa.edu.au/undergraduate/courses/230.300/readings/graphapplet/graph.html • Multicast • Steiner Tree

  21. Routing Strategies • Source routing • centralized problem, loop-free • need global state, computation overhead • Distributed routing • routing response faster, scalable • need global state, more messages, loops • Hierarchical routing • scales well, computation shared • imprecision because aggregate state, complicated with constraints,

  22. Future Directions • Efficient Routing Algorithms • Routing with imprecise state information • Multipath Routing • Rerouting

  23. QoS Routing for Multimedia • Metric Selection • Efficient algorithms must exist for path computation • Reflect basic information of network • orthogonal • Multiple Metrics • additive, multiplicative, concave

  24. Bandwidth and Delay as Metrics • finding path subject to two or more additive and multiplicative metrics is NP-complete • only feasible combination is bandwidth and, for example, delay

  25. Path Computation Algorithms • Source Routing • Hop-by-hop • compute best path to every destination • shortest-widest path is free of loops

  26. References • “NetScope: Traffic Engineering for IP Networks,” A. Feldmann, A. Greenberg, C. Lund, N. Reingold, and J. Rexford, IEEE Network, Mar./Apr. 2000, pp. 11-19 • “Traffic Engineering with MPLS in the Internet,” X. Xiao, A. Hannan, B. Bailey, and L.M. Ni, Ibid., pp. 28-33 • “Capacity Management and Routing Policies for Voice over IP Traffic,” P.P. Mishra, and H. Saran, Ibid, pp. 20-27 • “Quality-of-Service Routing for Supporting Multimedia Applications,” Z. Wang, and J. Crowcroft, IEEE Journal on Selected Areas in Communications, Vol. 14, No. 7, Sept. 1996 • “An Overview of Quality of Service Routhing for Next-Generation High-Speed Networks: Problems and Solutions,” S. Chen and K. Nahrstedt, IEEE Network, Nov./Dec. 1998, pp. 64-79

More Related