PCE Communication Protocol Application Model

1
PCE Communication Protocol Application Model

• draft-zhang-pce-comm-app-model-01.txt
• Zhang Renhai zhangrenhai_at_huawei.com

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Foreseeable problem

• In a PCE-based TE environment where multiple
  stateful PCEs are responsible for the path
  computation
• How to avoid the resources contention when
  re-establishing many LSPs at a time after a
  inter-as TE link fail and recovery
• How to reasonably make the computation load
  balacing among these PCEs
• How to get the PCEs quickly informed the changed
  resources information

3
motivation

• A scenario about the application of the PCE
  protocol
• With corresponding mechanism to solve some
  foreseeable problems
• The proposal may need some supports of the PCE
  communication protocol and PCE discovery
  protocol.

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summary

• For the environment of the distributed and
  stateful PCE
• each request (including hard resources request
  and only the computation of a path) is sent to
  all PCEs in a domain, certainly, only one pce is
  responsible for the request
• LSPs are reported to all PCEs by the originators
  of the LSPs when established for fast
  synchronization.

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Global Computing Table

• A table contained in each PCE holding all current
  requests (being and to be served) in a domain
• With the table and a consistent decision
  mechanism, all resources in the domain can be
  managed through among the PCEs

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Global Computing Table

• Furthermore, computation load balancing also can
  be performed among the PCEs.
• All PCEs in a domain can be treated as a whole
  PCE
• With this table, each PCE can know the number of
  requests that other PCEs are serving
• Only generic capabilities are announced to PCCs
• Detailed capabilities are exchaned among PCEs
• In case of the PCCs fault selection of PCE for a
  request, PCE can help to select the right one for
  the request and inform it in the Reply message,
  reduce the bandwidth consumpution (PCEs dont
  need to announce the detailed capabilities to
  PCCs).

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Next steps

• Interested in this work?
• Please send your comments to me and PCE mailing
  list.