MPLS and Traffic Engineering CMPT Spring Liang Zhou Jiang (Jeff)

Outline Traffic engineering in IP Networks Multiprotocol Label Switching MPLS Applications Traffic Engineering with MPLS CMPT 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 CMPT Spring Liang Zhou Jiang (Jeff)

BGP Topology CMPT 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 CMPT 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 CMPT 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 CMPT Spring Liang Zhou Jiang (Jeff)

MPLS – Cont’ CMPT Spring Liang Zhou Jiang (Jeff)

MPLS – Cont’ 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 CMPT Spring Liang Zhou Jiang (Jeff)

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 CMPT Spring Liang Zhou Jiang (Jeff)

MPLS – Cont’ CMPT Spring Liang Zhou Jiang (Jeff)

MPLS – Cont’ CMPT 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 CMPT 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 CMPT 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. CMPT 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. ( bytes) "Multiprotocol Label Switching Architecture", Ross Callon, A. Viswanathan, E. Rosen, 08/27/1999. ( 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. ( 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 CMPT Spring Liang Zhou Jiang (Jeff)