Zafar Ali (zali@cisco) George Swallow (swallow@cisco) Rahul Aggarwal (rahul@juniper)

169th IETF, MPLS WG, Chicago, July 200769th IETF, MPLS WG, Chicago, July 2007

Non PHP Behavior and out-of-band mapping for RSVP-TE LSPs

draft-ali-mpls-rsvp-te-no-php-oob-mapping-01.txt

Zafar Ali ([email protected])George Swallow ([email protected])

Rahul Aggarwal ([email protected])


Agenda

• Application Space and Requirement.

• Proposed Solution.

• Next Steps.


Application Space and Requirement

• Application Space Scenarios where Egress LSR receives the binding of the RSVP-TE LSP to an application, using an "out-of- band" (OOB) mechanism (e.g., using BGP). MVPN, VPLS, etc.

• Requirements Induced In order to apply the binding information, the Egress needs to identify the incoming LSP (using local label). Therefore, non Penultimate Hop Popping (non-PHP) behavior is required at the Egress for OOB mapping. Egress LSR cannot make correct forwarding decision until such OOB mapping information is received.

• Other applications of non-PHP Behavior Enables multicast routing to perform RPF check on the packets coming from the MPLS core. Enables Egress LSR to determine whether traffic is received on the expected P2MP LSP. Non-PHP behavior is also required to determine the context of upstream assigned labels, when the context is a MPLS LSP.


Proposed Solution

• This document defines two new optional bits in the Attributes Flags TLV of the LSP_ATTRIBUTES Object defined in [RFC4420].

Bit Number 6 (TBD): non-PHP behavior desired bit.

Bit Number 7 (TBD): OOB mapping indication bit.

• The procedures are equally applicable for P2P and P2MP LSPs.

• Non-PHP behavior desired and OOB mapping indication bit can appear and be processed independently of each other.

• An Ingress node requesting OOB mapping MAY also set non-PHP behavior desired bit (As OOB mapping requires non-PHP behavior).


Next Steps

• We would like to request WG to accept this ID as a WG document.


Backup Slides


Signaling and Enforcing non-PHP Behavior

• Set by Ingress node in the Attributes Flags TLV of the LSP_ATTRIBUTES object in the Path message for the LSP that desires Non-PHP behavior.

• Egress node supporting the “non-PHP behavior desired bit” MUST allocate a non-NULL local label.

• Ignored in all other cases (i.e., optional) and by all other nodes.

• An ingress node requesting non-PHP behavior MAY examine the label value corresponding to the Egress node(s) in the RRO, and MAY send a Path Tear to the Egress which assigns a Null label value.


Signaling OOB Mapping Indication

• Set by Ingress node in the Attributes Flags TLV of the LSP_ATTRIBUTES object in the Path message for the LSP that desires OOB mapping.

• Egress node supporting the “OOB mapping indication bit”, waits for the OOB mapping before accepting traffic on the P2MP LSP.

RSVP-TE signaling completion and the OOB mapping information reception happen asynchronously at the Egress.

• Ignored in all other cases (i.e., optional) and by all other nodes.

• Egress proceeds with RSVP-TE signaling and sends RESV messages as per regular RSVP-TE procedures.

• Egress overwrites the signaled value of L3PID in the Label Request Object with the L3PID is also obtained from OOB mapping (if available).


Egress Procedure for label binding and cleanup

• RSVP-TE signaling completion and the OOB mapping information reception happen asynchronously at the Egress.

• Egress waits for the OOB mapping before accepting traffic on the P2MP LSP.

• In order to avoid unnecessary use of the resources and possible block-holing of traffic, if the OOB mapping information is not received within a reasonable time, Egress MAY trigger a Path Error message with the error code/sub-code "Notify Error/ no OOB mapping received" for all affected LSPs.

Zafar Ali (zali@cisco) George Swallow (swallow@cisco) Rahul Aggarwal (rahul@juniper)

Documents

Transcript of Zafar Ali (zali@cisco) George Swallow (swallow@cisco) Rahul Aggarwal (rahul@juniper)