Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Segment Routing: MPLS & Ethernet World Congress 2013

7,353 views

Published on

Published in: Technology, Education

Segment Routing: MPLS & Ethernet World Congress 2013

  1. 1. Segment RoutingClarence Filsfils – cf@cisco.comDistinguished Engineer© 2013 Cisco and/or its affiliates. All rights reserved. 1
  2. 2. •  Introduction•  Technology•  Use Cases•  Conclusion© 2013 Cisco and/or its affiliates. All rights reserved. 2
  3. 3. Introduction© 2013 Cisco and/or its affiliates. All rights reserved. 3
  4. 4. •  Leverage the efficient MPLS dataplane•  Leverage all the services supported over MPLS© 2013 Cisco and/or its affiliates. All rights reserved. 4
  5. 5. •  Simplicity –  less protocols to operate –  less protocol interactions to troubleshoot –  avoid directed LDP sessions between core routers –  deliver automated FRR for any topology•  Scale –  avoid millions of labels in LDP database –  avoid millions of TE LSP’s in the network –  avoid millions of tunnels to configure© 2013 Cisco and/or its affiliates. All rights reserved. 5
  6. 6. •  Applications must be able to interact with the network –  cloud based delivery –  internet of everything•  Programmatic interfaces and Orchestration –  Necessary but not sufficient•  The network must respond to application interaction –  Rapidly-changing application requirements –  Virtualization –  Guaranteed SLA and Network Efficiency© 2013 Cisco and/or its affiliates. All rights reserved. 6
  7. 7. •  Simple to deploy and operate –  Leverage MPLS services & hardware –  straightforward ISIS/OSPF extension to distribute labels –  LDP/RSVP not required•  Provide for optimum scalability, resiliency and virtualization•  Perfect integration with application –  simple network, highly programmable –  highly responsive© 2013 Cisco and/or its affiliates. All rights reserved. 7
  8. 8. •  SR EFT is available! –  12k, ASR9k, CRS1, CRS3 –  ask to test it at the Cisco/Cariden booth on Thursday –  get it to your lab•  Working aggressively with lead customers towards productization© 2013 Cisco and/or its affiliates. All rights reserved. 8
  9. 9. •  Simple ISIS/OSPF extension•  Welcoming contribution© 2013 Cisco and/or its affiliates. All rights reserved. 9
  10. 10. •  Ahmed Bashandy•  Bertrand Duvivier•  Clarence Filsfils•  Dan Frost•  David Ward•  Stefano Previdi•  Stewart Bryant© 2013 Cisco and/or its affiliates. All rights reserved. 10
  11. 11. Segment Routing© 2013 Cisco and/or its affiliates. All rights reserved. 11
  12. 12. •  Forwarding state (segment) is established by IGP –  LDP and RSVP-TE are not required –  Agnostic to forwarding dataplane: IPv6 or MPLS•  MPLS Dataplane is leveraged without any modification –  push, swap and pop: all what we need –  segment = label•  Source Routing –  source encodes path as a label or stack of segments –  two segments: node or adjacency© 2013 Cisco and/or its affiliates. All rights reserved. 12
  13. 13. A packet injected at A B C D node C with label Pop Z 65 9003 is forced 9003 through datalink CO M N O P•  C allocates a local label•  C advertises the adjacency label in ISIS –  simple sub-TLV extension•  C is the only node to install the adjacency segment in MPLS dataplane© 2013 Cisco and/or its affiliates. All rights reserved. 13
  14. 14. 9105 9107 9107 9101 9103 9103 9105 9105 9105 9107 B C D 9103 9101 9105 9105 A 9107 Z N O P 9105 9103 9103 9105 9105•  Source routing along any explicit path –  stack of adjacency labels•  SR provides for entire path control© 2013 Cisco and/or its affiliates. All rights reserved. 14
  15. 15. Pop 9003 9001 switches on blue member Pop 9001 B C 9002 switches on green member Pop 9002 9003 load-balances on any Pop 9003 member of the adj•  Adjacency segment represents a specific datalink to an adjacent node•  Adjacency segment represents a set of datalinks to the adjacent node© 2013 Cisco and/or its affiliates. All rights reserved. 15
  16. 16. •  SR requires only 1 label per node in the IGP domain –  insignificant: < 1% of label space•  Node SR Range –  a range of labels allocated to the SR control-plane –  e.g. [64, 5000]•  Each node gets one unique label from SR Range –  Node Z gets label 65© 2013 Cisco and/or its affiliates. All rights reserved. 16
  17. 17. FEC Z swap 65 swap 65 push 65 to 65 to 65 pop 65 A B C D A packet injected Z 65 anywhere with top label 65 will reach Z via shortest-path•  Z advertises its node segment –  simple ISIS sub-TLV extension•  All remote nodes install the node segment to Z in the MPLS dataplane© 2013 Cisco and/or its affiliates. All rights reserved. 17
  18. 18. FEC Z swap 65 swap 65 push 65 to 65 to 65 pop 65 A B C D A packet injected Z 65 anywhere with top 65 65 65 label 65 will reach Z Packet to Z Packet to Z Packet to Z Packet to Z Packet to Z via shortest-path•  Z advertises its node segment –  simple ISIS sub-TLV extension•  All remote nodes install the node segment to Z in the MPLS dataplane© 2013 Cisco and/or its affiliates. All rights reserved. 18
  19. 19. 72 72 9003 9003 9003 65 65 65 Packet to Z Packet to Z Packet to Z 72 72 A B C D Pop Z 9003 65 M N O P 65 Packet to Z 65 65 Packet to Z Packet to Z•  Source Routing•  Any explicit path can be expressed: ABCOPZ© 2013 Cisco and/or its affiliates. All rights reserved. 19
  20. 20. 72 72 78 78 78 65 65 65 Packet to Z Packet to Z Packet to Z 72 72 A B C D 78 Z 65 M N O P 65 Packet to Z 65 65 Packet to Z Packet to Z•  Node Segment is at the heart of the proposal –  ecmp multi-hop shortest-path –  in most topologies, any path can be expressed as list of node segments© 2013 Cisco and/or its affiliates. All rights reserved. 20
  21. 21. Nodal segment to C Nodal segment to C A B C D Adj Segment Z M N O P Nodal segment to Z•  Simple extension•  Excellent Scale: a node installs N+A FIB entries –  N node segments and A adjacency segments© 2013 Cisco and/or its affiliates. All rights reserved. 21
  22. 22. •  IP-based FRR is guaranted in Backbone any topology –  2002, LFA FRR project at Cisco C1 C2 –  draft-bryant-ipfrr-tunnels-03.txt•  Directed LFA (DLFA) is E1 E4 guaranteed when metrics are symetric 1000 E2 E3•  No extra computation (RLFA) Adj segment Node segment to P node to Q node•  Simple repair stack –  node segment to P node –  adjacency segment from P to Q Default metric: 10© 2013 Cisco and/or its affiliates. All rights reserved. 22
  23. 23. Use Cases© 2013 Cisco and/or its affiliates. All rights reserved. 23
  24. 24. A B PE1 PE2 M N All VPN services ride on the node segment to PE2•  Efficient packet networks leverage ecmp-aware shortest-path! –  node segment!•  Simplicity –  no complex LDP/ISIS synchronization to troubleshoot –  one less protocol to operate© 2013 Cisco and/or its affiliates. All rights reserved. 24
  25. 25. •  An SR core router scales much than with RSVP-TE –  The state is not in the router but in the packet –  N+A vs N^2 N: # of nodes in the network A: # of adjacencies per node © 2013 Cisco and/or its affiliates. All rights reserved. 25
  26. 26. SR avoids state in the core SR avoids enumerating RSVP-TE tunnels for each ECMP paths•  A sends traffic with [65] Classic ecmp “a la IP”•  A sends traffic with [111, 65] Packet gets attracted in blue plane and then uses classic ecmp “a la IP”© 2013 Cisco and/or its affiliates. All rights reserved. 26
  27. 27. •  Tokyo to Brussels –  data: via US: cheap capacity –  voip: via russia: low latency•  CoS-based TE with SR –  IGP metric set such as >  Tokyo to Russia: via Russia Node segment to Brussels >  Tokyo to Brussels: via US Node segment to Russia >  Russia to Brussels: via Europe –  Anycast segment “Russia” advertised by Russia core routers•  Tokyo CoS-based policy –  Data and Brussels: push the node segment to Brussels –  VoIP and Brussels: push the anycast node to Russia, push Brussels© 2013 Cisco and/or its affiliates. All rights reserved. 27
  28. 28. B C D 9101 9101 9101 9105 9105 9107 A 9107 Z 9105 9103 9105 N O P 9101 9103•  For Traffic Engineering•  or for OAM Nanog57, Feb 2013© 2013 Cisco and/or its affiliates. All rights reserved. 28
  29. 29. 65 2G from A to Z please FULL 65 Link CD is full, I cannot use the shortest-path 65 straight to Z•  The network is simple, highly programmable and responsive to rapid changes –  perfect support for centralized optimization efficiency, if required© 2013 Cisco and/or its affiliates. All rights reserved. 29
  30. 30. Tunnel AZ onto {66, 68, 65} 66 FULL 68 65 Path ABCOPZ is ok. I account the BW. Then I steer the traffic on this path•  The network is simple, highly programmable and responsive to rapid changes© 2013 Cisco and/or its affiliates. All rights reserved. 30
  31. 31. Millions of Applications•  Each engineered application flow is flows mapped on a path –  millions of paths A path is•  A path is expressed as an ordered list mapped on a list of of segments segments•  The network maintains segments The network –  thousands of segments only maintains segments –  completely independent of application No application size/frequency state•  Excellent scaling and virtualization –  the application state is no longer within the router but within the packet© 2013 Cisco and/or its affiliates. All rights reserved. 31
  32. 32. Conclusion© 2013 Cisco and/or its affiliates. All rights reserved. 32
  33. 33. •  Simple to deploy and operate –  Leverage MPLS services & hardware –  straightforward ISIS/OSPF extension•  Provide for optimum scalability, resiliency and virtualization•  Perfect integration with application•  EFT and IETF available – test and contribute© 2013 Cisco and/or its affiliates. All rights reserved. 33

×