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									MPLS and Traffic
Engineering



    CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
Outline

   Traffic engineering in IP Networks

   Multiprotocol Label Switching

   MPLS Applications

   Traffic Engineering with MPLS


                      CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
Traffic Engineering in IP Networks
   Coping with Internet growth
       Network architecture
       Capacity expansion
            Increase the number of circuits
            Increase the bandwidth of existing circuits
            Increase the capacity of the core routers
            Add more core routers
       Traffic engineering
            Wait until QoS becomes ubiquitous and leverage it for admission
             control
            Better utilize all available bandwidth in the core


                                 CMPT771 - 2008 Spring      Liang Zhou Jiang (Jeff)
BGP Topology




           CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
    Internet Traffic Engineering
   Motivation
      Architecture paradigms and simple capacity expansion are necessary, but
        not sufficient, to deliver high quality Internet service under all
        circumstances.
   Definition
      The aspect of Internet network engineering that addresses the issue of
        performance optimization of operational networks.
      Application of technology and scientific principles to the
           measurement

           Modeling

           Characterization

           Control of Internet traffic

      Application of knowledge and techniques to achieve specific performance
        objectives.
   Goal and purpose
      Reliable and expeditious movement of traffic through the network
      Efficient utilization of network resources
      Planning of network capacity
                                  CMPT771 - 2008 Spring       Liang Zhou Jiang (Jeff)
Conventional IP Technologies
   Advantages
       Highly distributed and scalable
   Disadvantages
     Doesn’t consider the characteristics of offered traffic and network
      capacity constrains when making routing decisions
     Inadequacy of measurement functions
     The limitations of intra-domain routing control functions
   Consequences
     Poor network resources allocation
     Some subnet resources become congested
     Some subnet resources along alternate paths remain underutilized




                                CMPT771 - 2008 Spring       Liang Zhou Jiang (Jeff)
                                CMPT771 - 2008 Spring        Liang Zhou Jiang (Jeff)

MPLS
   Idea: leverage layer 3 interior routing protocols (OSPF and IS-IS) to calculate
    shortest paths to all possible destinations, but then assign a sequence of
    labels/tags along each path.
   Label Switched Path (LSP) and LSP tunnel
           CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)

MPLS – Cont’
    MPLS – Cont’                            CMPT771 - 2008 Spring             Liang Zhou Jiang (Jeff)

   Traffic parameters
      Adaptivity attributes
      Priority attributes
      Preemption attributes
      Resilience attributes
      Resource class affinity attributes
      Policing attributes
   Components of the MPLS Traffic Engineering Model
      Path management
             Path selection

             Path placement

             Path maintenance

      Traffic assignment
             Partitioning function – partition ingress traffic according to some principle of
              division
             Apportionment function – allots the partitioned traffic to established LSP tunnels
              according to some principle of allocation
      Network state information dissemination
             Extending conventional IGP to propagate additional information: Maximum link
              bandwidth, maximum allocation multilplier default traffic engineering metric,
              reserved bandwidth per priority class, and resource class attributes
        Network management
    MPLS Applications
   Short cut routing
     BGP Next Hop
     A MPLS Short Cut to BGP Next Hop
   Tunnel Restoration
     Planned Head   End Reroute Capability
     Fast Reroute
   Integrating MPLS and QoS
     Integrated Services
     Differentiated Services
     IntServ Meets DiffServ and   MPLS at the Internet Core


                         CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
MPLS – Cont’




          CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
MPLS – Cont’




           CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
MPLS – Cont’
   L-LSP’s for Mapping DiffServ to MPLS
   E-LSP’s for Mapping DiffServ to MPLS
   Major components of Traffic Engineering with MPLS
     User interface for articulating traffic engineering policy in terms of
      constraints to conventional SPF
     IGP component which is composed of traffic engineering extensions to
      IS-IS and OSPF
     Signaling component which is based on traffic engineering extensions to
      RSVP or CR-LDP
     Traffic Engineering Policy




                              CMPT771 - 2008 Spring      Liang Zhou Jiang (Jeff)
Traffic Engineering with MPLS
   Administratively Specified Explicit Path Selection
   Resource Class Affinity
   Label Switched Path Adaptivity
   Label Switched Path Bandwidth Reservation Priority
   Label Switched Path Preemption
   Load Distribution Across Parallel Label Switched Paths
   Label Switched Path Resilience




                        CMPT771 - 2008 Spring   Liang Zhou Jiang (Jeff)
Conclusion
The resiliency and adaptability of the Internet is unparalleled in the history of
communications. The Internet, with its growing suite of open and standardized
protocols, is the clear winner in the inevitable convergence of private line,
voice, video, and outsourced data services. MPLS is only the latest entrant in
this remarkable evolution. MPLS when combined with traffic engineering
deliver a formable tool for meeting the rigid requirements of differentiated
services by leveraging the strengths of IP routing, the proven scalability of
terabit routers, and the mechanisms for end to end QoS.




                                CMPT771 - 2008 Spring        Liang Zhou Jiang (Jeff)
References
   "A Framework for MPLS", Ross Callon, George Swallow, N. Feldman, A.
   Viswanathan, P. Doolan, A. Fredette, 09/22/1999. (180569 bytes)
   "Multiprotocol Label Switching Architecture", Ross Callon, A. Viswanathan, E.
   Rosen, 08/27/1999. (145481 bytes)
   "MPLS Label Stack Encoding", Dino Farinacci, Tony Li, A. Conta, Y Rekhter, Dan
   Tappan, E. Rosen, G. Fedorkow, 09/13/1999. (46971 bytes)
   "Extensions to RSVP for LSP Tunnels", Der-Hwa Gan, Tony Li, George Swallow,
   Lou Berger, Vijay Srinivasan, Daniel Awduche, 09/29/1999. (105164 bytes)
   "MPLS Support of Differentiated Services", Bruce Davie, Pasi Vaananen, Liwen Wu,
   Francois Le Faucheur, Pierrick Cheval, Ram Krishnan, Shahram Davari, 10/11/1999.
   "Applicability Statement for Extensions to RSVP for LSP-Tunnels", Alan Hannan,
   Daniel Awduche, X Xiao, 10/05/1999. (17395 bytes)
   “MPLS Optimized Multipath (MPLS--OMP)”, Curtis Villamizar, February 25, 1999
   "OSPF Optimized Multipath (OSPF-OMP)", Curtis Villamizar, 02/25/1999. (90622
   bytes)
   “IS-IS Extensions for Traffic Engineering”, Henk Smit, Tony Li, May 1999
   “OSPF Extensions for Traffic Engineering” Derek M. Yeung, February 1999
   “RSVP Label Allocation for Backup Tunnels”, Robert Goguen, George Swallow,
   October 1999




                                      CMPT771 - 2008 Spring             Liang Zhou Jiang (Jeff)

								
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