Page - 1 IETF 76, Hiroshima, November 8-13, 2009

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

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

Yuanlin BaoXihua FuGang Xie

ZTE Corporation

Page - 2 IETF 76, Hiroshima, November 8-13, 2009

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

Page - 3 IETF 76, Hiroshima, November 8-13, 2009

B

PCE

Client2

C

D

E

F

GClient1

UNI UNI

A

Application

request a service to Client2 with a pre-computed routing service level

compute a primary route and a pre-computed route to node G

primary route{A,B,C,G}pre-computed route {A,D,F,G}

signal the service

pre-computed route {A,D,F,G} is affected,find another one ...

new pre-computed route {A,D,E,F,G}

Oh, link BC is cut ... Aha! I’m not scared!

I have pre-computed route {A,D,E,F,G}

signal the service with the pre-computed route

Primary route {A, B, C, G}Pre-computed route {A,D,F,G}{A,D,E,F,G}

Page - 4 IETF 76, Hiroshima, November 8-13, 2009

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

Page - 5 IETF 76, Hiroshima, November 8-13, 2009

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-type=3: Pre-Computed Routing Service

cancelled• Notification-value=1: PCC cancels one pre-computed

routing service• Notification-value=2: PCC cancels all pre-computed

routing services it requested

Page - 6 IETF 76, Hiroshima, November 8-13, 2009

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