1. 1 PCE Communications Protocol Requirements (draft-ash-pce-comm-protocol-reqs-00.txt) Design Team Jerry Ash (AT&T) Alia Atlas (Avici) Arthi Ayyangar (Juniper) Igor Bryskin (Independent Consultant) Dean Cheng (Cisco) Durga Gangisetti (MCI) Kenji Kumaki (KDDI) Jean-Louis Le Roux (France Telecom) Eiji Oki (NTT) Raymond Zhang (Infonet)

2. 2 Outline qPCE communication protocol applications qrequirements qissues raised on list qnext step: working group draft

3. 3 PCE Communication Protocol Application External PCE Node

4. 4 PCE Communication Protocol Application Multiple PCE Path Computation

5. 5 PCE Communication Protocol Application Multiple PCE Path Computation with Inter-PCE Communication

6. 6 PCE Communications Protocol Relationship to PCE Discovery qPCE discovery mechanism/protocol not included as part of PCE communications protocol vseparate PCE discovery protocol/mechanism qPCC MAY use information in PCE communications protocol derived from PCE discovery protocol/mechanism ve.g., PCC may learn location of one or more PCEs from the discovery protocol/mechanism vPCC can pick one PCE & start to exchange communication protocol messages with the PCE qalso, an operator MAY configure location of PCE for the PCC qtwo methods not exclusive vPCC may choose a desired PCE from what it learnt from PCE discovery or being configured

7. 7 PCE Communications Protocol Requirements qPCE communication protocol MUST support vcommunication between PCC-PCE & PCE-PCE in (G)MPLS networks –one protocol for both cases vreliable message exchange –reliable transport –request-response message exchange vsecurity of PCC-PCE & PCE-PCE messages –encryption for some data fields, prevent snooping –authentication, prevent spoofing –DoS protection vconfidentiality of PCE communication messages, possibly across multiple domains –little coordination of SP internal topology –use loose routes –replace ERO segment with cookie entry point to domain consults local PCE using cookie to retrieve next ERO segment

8. 8 PCE Communications Protocol Requirements qPCE communication protocol MUST support vprotocol recovery procedures –graceful restart for stateful PCE vscale well with the following –number of PCCs –number of PCEs –TED size (number of links/nodes) –number of domains vminimize communication overhead qPCE communication protocol SHOULD support vcollection of TE information –LSP traffic volume, LSP route

9. 9 PCE Communications Protocol Requirements qPCE communication protocol MUST support operation in various SP/networking environments vIP-MPLS, GMPLS, & optical networks vP2P path computation vintra/inter-domain & inter-layer path computation vinter-layer reconfiguration & path setup/release –path computation triggered by higher-layer PCC, PCE, or lower-layer PCC PCE optionally triggers inter-layer path computation based on traffic/topology change or failure –lower-layer path established/released if necessary use (optional) support setup/release request/reply messages vcentralized & distributed computation model vsingle & multiple PCE path computation vexternal PCE node vstateful & stateless PCEs vsynchronized & non-synchronized PCE

10. 10 PCE Communications Protocol Requirements qPCC-PCE & PCE-PCE path request message MUST support carrying various constraints including (but not limited to): vpath source/destination vdesired bandwidth, minimum bandwidth, QoS parameters (e.g., hop count, delay, preemption priority, etc.) vdiversity, SRLGs, optical impairments, wavelengh continuity vmaximum number of paths vnumber of disjoint paths required –if near-disjoint paths acceptable vloose path to be expanded vpath previously returned (useful for stateless PCEs) vlink/node protection capability –multiple correlated paths for protection

11. 11 PCE Communications Protocol Requirements qPCC-PCE & PCE-PCE path request message MUST support carrying various constraints including (but not limited to): vresources (links/nodes), resource affinities & SRLGs to use/avoid –exclusions unsorted list of links/nodes/SRLGs that must not appear in the resulting path(s) –inclusions sorted list of links/nodes that must appear in resulting path(s) in specified order strict & loose inclusions »specify if additional links can appear in resulting path(s) –sharables unsorted list of links that must not be excluded in resulting path(s) because of insufficient resources vswitching type, encoding type, GPID vswitching capabilities to be included/excluded from the path vcarrying multiple requests, correlated or not

12. 12 PCE Communications Protocol Requirements qPCC-PCE & PCE-PCE path request message MUST support ability to prefer/customize various path computation algorithms & policies vshortest intra/inter-domain TE paths –not require full graph to compute shortest/diverse path –recursive CSPF computation vreoptimization for intra/inter-domain TE paths vcomplex routing requiring high CPU & memory –multiple constraints, e.g. bounded delay minimum cost path vbackup path computation vQoS CAC

13. 13 PCE Communications Protocol Requirements qPCE-PCC & PCE-PCE path response message MUST support returning various objects including (but not limited to): vprimary & alternate P2P paths vexplicit or strict/loose routing path vprimary & backup path (for FRR) vless-constrained path (if cannot find path satisfying all constraints) vindication of PCE inability to support service/constraint –specify services/constraints PCE can support va cookie, in case path must be hidden

14. 14 PCE Communications Protocol Requirements qPCE communication protocol SHOULD account for future extensions not currently in PCE WG scope vP2MP paths qPCE communication protocol SHOULD consider reuse of existing encodings for data objects in signaling & management protocols qPCE communication protocol candidates vRSVP-TE extensions –http://www.watersprings.org/pub/id/draft-vasseur-mpls- computation-rsvp-05.txt vTCP extensions –http://www.watersprings.org/pub/id/draft-lee-mpls-path- request-04.txt vLDP extensions vBGP extensions vPCE  GMPLS controller –draft-oki-ccamp-gtep-01.txt vother

15. 15 Issues Raised on List qconsiderable discussion about re-use of encodings vproposed wording: PCE communication protocol SHOULD consider reuse of existing encodings for data objects in signaling & management protocols qsome suggestions to remove listing of PCE communication protocol candidates

16. 16 Next Steps qpropose draft as PCE WG draft