Signaling RSVP-TE P2MP LSPs in an Inter-domain Environment draft-ali-mpls-inter-domain-p2mp-rsvp-te-lsp-01.txt Zafar Ali, Cisco Systems

RSVP-TE P2MP LSPs in an Inter-domain Environment Path computation for P2MP LSP that span multiple domain is a difficult problem to solve (e.g., Steiner tree computation for P2MP LSP is NP-hard). BRPC based heuristic extensions for P2MP-TE is a work in progress. End-to-end Path has to be remerged free (may also need to be cross-over free). Need for finding an end-to-end path that is remerge free also increases chances for crankbacks during setting up a P2MP LSP. Crankback mechanisms for P2MP LSP are not addressed by RFC4875. P2MP LSPs may need to be stitched at the border nodes, or hierarchical P2MP LSPs. Loose hop expansion at the border node such that overall P2MP LSP is remerge free. Some of these aspects are also applicable to intra-domain environment. 73th IETF, MPLS WG, Minneapolis, MN, USA November 2008

Loose Hop Expansion at the Border Node Document proposes a notion of passing a list of addresses to a border node, for all S2Ls of a P2MP LSP that transits from that border node. This list of addresses contains addresses for which the given border node needs to expend the EROs to, for all S2L of the P2MP LSP that transit through the border router. When ERO in the Path message of a P2MP LSP contains a loose hop, the Path message MAY (optionally) contain a "Related Addresses for Sibling S2L sub-LSP" object for each loose hop specified in the ERO. When multiple S2Ls are carried in the single Path messages, the path message may aggregate all related siblings that transits from that border node. 73th IETF, MPLS WG, Minneapolis, MN, USA November 2008

73th IETF, MPLS WG, Minneapolis, MN, USA November 2008 Next Steps This is a work in progress. Looking for comments/ feedback on the document. 73th IETF, MPLS WG, Minneapolis, MN, USA November 2008

73th IETF, MPLS WG, Minneapolis, MN, USA November 2008 Thank You. 73th IETF, MPLS WG, Minneapolis, MN, USA November 2008