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Jianping Wu Yong Cui Xing Li Tsinghua University / CERNET Chris Metz Gargi Nalawade Simon Barber

A Framework for Softwire Mesh Signaling, Routing and Encapsulation across Backbone Networks draft-wu-softwire-mesh-framework-00. Jianping Wu Yong Cui Xing Li Tsinghua University / CERNET Chris Metz Gargi Nalawade Simon Barber Pradosh Mohapatra Cisco Systems, Inc. Problem to Solve.

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Jianping Wu Yong Cui Xing Li Tsinghua University / CERNET Chris Metz Gargi Nalawade Simon Barber

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  1. A Framework for Softwire Mesh Signaling, Routing and Encapsulationacross Backbone Networksdraft-wu-softwire-mesh-framework-00 Jianping Wu Yong Cui Xing Li Tsinghua University / CERNET Chris Metz Gargi Nalawade Simon Barber Pradosh Mohapatra Cisco Systems, Inc.

  2. Problem to Solve • draft-ietf-softwire-problem-statement-02.txt • describes softwire mesh scenario and requirements • Basically we need a generalized, network-based solution for supporting client IP AF(i)-over-backbone IP AF(j) routing and forwarding • e.g. IPv4-over-IPv6, IPv6-over-IPv4, VPNv6-over-IPv4, etc.

  3. Same as a dual-stack backbone SW IPv4 static or eBGP peering Encapsulation and Setup IPv4 Access IPv4 Access edge edge CERNET2 Backbone IPv4 Access IPv4 Access edge edge IPv6 Access IPv6 Access Native IPv6 backbone CERNET2 Requirements

  4. Reference Model of Mesh Solution | | | | | | | | | |<------<SW Signaling>------>| | | | | | |<---AF(i)---->|<----<BGP: AF(i)prefixes,-->|<-----AF(i)--->| | Routing | SW_NHOP> | Routing | | | | | +-------+ +-------+ +-------+ +-------+ |AF(i) | | | (Single AF(j)) | | |AF(i) | |Access |------| AFBR |===(Transit Core)===| AFBR |------|Access | |Island | |AF(i,j)| |AF(i,j)| |Island | +-------+ +-------+ +-------+ +-------+ /|\ /|\ | | | [STH] | ---[SPH]---->SW Encap=======[SPH]==========>SW Decap---[SPH]---> [payload] [payload] [payload] AFBR=Address Family Border Router SPH=Softwire Payload Header STH=Softwire Transport Header

  5. Softwire Signaling BGP Update RR SW Encap Set SW Tunn IDSW End-Point Addr • AFBR 1 advertises the following to AFBR 2, …, AFBR N: • softwire encap set, softwire tunnel ID and softwire end-point • Now AFBR 2, … AFBR N have learned the SW encap set and SW tunnel with end-point address to use when forwarding packets to prefixes advertised by AFBR 1 IP AF (i) Access Island IP AF (j) Transit Core AFBR 2 IP AF (i) Access Island AFBR 1 . . IP AF (i) Access Island AFBR N = Softwire

  6. Softwire Signaling Drafts MP_REACH_NLRI • draft-nalawade-kapoor-tunnel-safi-05.txt • defines a new tunnel SAFI=64 contained in MP_REACH_NLRI • NLRI value contains tunnel ID: tunnel IPv4/IPv6 address • draft-nalawade-softwire-mesh-encap-attribute-00.txt • defines a payload type carried inside softwire • TLVs for encap types (e.g. IPnIP, GRE, etc.), encap parameters, and preferences +---------------------------------------------------------+ | AFI (IPv4=1, IPv6=2) | +---------------------------------------------------------+ | SAFI (TUNNEL=64) | +---------------------------------------------------------+ | Length of Next Hop Network Address (1 octet) | +---------------------------------------------------------+ | Network Address of Next Hop (variable) | +---------------------------------------------------------+ | Reserved (1 octet) | +---------------------------------------------------------+ | SW Tunnel ID=2 Octets: SW End-Point Address (IPv4/IPv6) | +---------------------------------------------------------+

  7. Softwire Routing and Tunnel Selection BGP Update IP AF(i) Prefix RR • AFBR 1 advertises: • IP AF(i) prefixes using BGP protocols • specific softwire-to-use to reach those prefixes (via SW_NHOP) • SW_NHOP attribute contains: • pointer to softwire tunnel-to-use leading to AFBR1 • IP AF(j) address that overrides next-hop address contained in MP_REACH_NLRI • draft-nalawade-softwire-nhop-00.txt specific SW to use to reach that prefix IP AF (j) Transit Core IP AF (i) Access Island IP AF (i) Access Island AFBR 1 AFBR 2 = Softwire

  8. Additional Softwire Items • OAM/MIBs • Security • control plane via TCP MD5 • data plane via encryption (e.g. IPsec) • apply L3VPN practices (RFC4111) • Multicast • possibilities are tunnel over unicast softwire mesh, extend mVPN, etc. • Inter-AS • Options A, B and C

  9. In summary • Dynamic and scalable method for IP(x)-over-IP(y) routing and forwarding needed • BGP ideal of softwire signaling • conveys softwire end-point addresses and sw encap sets • BGP ideal for softwire routing and tunnel selection • employ existing multi-AF BGP solutions • include SW_NHOP attribute to link reachability with softwire encap action and next_hop address • Re-use existing IP (and MPLS) tunnel encapsulation schemes • Generalized for any client IP AF(x)-over-IPv4/IPv6/MPLS backbones

  10. Next Steps • Request that the following become Softwires WG documents • draft-wu-softwire-mesh-framework-00 • draft-nalawade-kapoor-tunnel-safi-05.txt • draft-nalawade-softwire-mesh-encap-attribute-00.txt • draft-nalawade-softwire-nhop-00.txt

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