A Path Computation Element PCE Application for Precomputed Routing

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A Path Computation Element (PCE) Application for
Pre-computed Routing

• draft-bao-pce-pre-configured-routing-00.txt

Yuanlin Bao Xihua Fu Gang Xie ZTE Corporation
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Background

• Traditional Pre-configured route
• pre-configured by NMS
• not used until primary route fails
• usually not be updated
• unavailablity
• need to be checked before used
• faster restoration can be achieved
• Pre-computed route
• Pce-based pre-configured route
• pre-configured route is misunderstanding in 00
  version, it will be substituted by pre-computed
  route in 01 version
• PCC asks for 2 (or more) routes, the first one
  will be signaled, the other will be kept in case
  a failure happens on the first route
• requested/cancelled by PCC
• dynamically updated according to network failure
  or the configured policy by pce
• provider can offer better service for customer

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Application
compute a primary route and a pre-computed route
to node G
pre-computed route A,D,F,G is affected, find
another one ...
primary routeA,B,C,G pre-computed route
A,D,F,G
A,D,F,G
A,D,E,F,G
new pre-computed route A,D,E,F,G
request a service to Client2 with a pre-computed
routing service level
Oh, link BC is cut ...
Aha! Im not scared! I have pre-computed route
A,D,E,F,G
signal the service with the pre-computed route
signal the service
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Requirements

• PCC
• SHOULD be able to request pre-computed routing
  service
• SHOULD be able to cancel pre-computed routing
  service
• PCE
• SHOULD be able to store the information of
  pre-computed routing service
• SHOULD be able to re-compute the pre-computed
  route according to network states change and
  other configured policy
• SHOULD be able to send the result of re-computed
  pre-computed route without PCC request

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PCEP extension

• New Flag Of RP Object
• Pre-Computed Routing Service Flag (bit 20)
• PCC use it to request pre-computed routing
  service
• PCE use it to send pre-computed route
• Extension to Notification Object
• Notification-type3 Pre-Computed Routing Service
  cancelled
• Notification-value1 PCC cancels one
  pre-computed routing service
• Notification-value2 PCC cancels all
  pre-computed routing services it requested

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Summary Next Steps

• The term pre-configured route is
  misunderstanding
• it will be substituted by pre-computed route
• Draft will continue to evolve
• Evaluating requirements
• Evaluating PCEP extentions
• Refine it according to the feedback from meeting
  or mailing list
• Comments are always appreciated