Presentation on theme: "BGP based Multi-homing in VPLS IETF-75"— Presentation transcript:
1 BGP based Multi-homing in VPLS IETF-75 Bhupesh KothariKireeti KompellaWim HenderickxFlorin Balus
2 Status draft-kothari-henderickx-l2vpn-vpls-multihoming-01.txt Common BGP based multi-homing procedures for LDP and BGP signaled VPLSDraft is based on:draft-kompella-l2vpn-vpls-multihoming-02.txtdraft-henderickx-l2vpn-vpls-multihoming-00.txt
4 Background: BGP VPLSPW infrastructure is created based on VE-IDs (RFC 4761)VE-ID=2BGP VPLSPE2ACVE-ID=1PE1PE3BVE-ID=3Single VE-ID on PE1 is sufficient for customer sites A and BVE-ID is assigned per VPLS instance irrespective of ACs (no customer site attached to PE3)
5 Background: LDP VPLSPW infrastructure is created based on procedures defined in RFC 4762LDP VPLSPE2ACPE1PE3BPWs can be created either using FEC-128 or FEC-129Procedures defined in this draft for LDP signaled VPLS do not depend on use of BGP Auto-discovery
6 Provisioning ModelMulti-homing Identifier (MH-ID): Same MH-ID must be configured on PEs connected to the same customer siteMH-ID=10VPLSPE3BPE1Customer site A dual-homed toPE devices for redundancyPE4APE2CMH-ID=10
7 Multi-homing NLRI VPLS Use of NLRI defined in RFC 4761 VE-ID field in the NLRI is set to MH-IDLB, OFF and LR are set to zeroMH-ID=10VPLSPE3BPE1PE4APE2CMH-ID=10MH-ID is not used to create PWs
8 Designated Forwarder Election Based on DF tie-breaking rules, PE1 is DFPE1:MH-ID=10, PREF=200VPLSPE1PE3BBased on DF election, PE3 can chose to not send traffic to PE2 (depends on whether there are additional sites on PE2 or not)APE2AC is put in non-forwarding statePE2:MH-ID=10, PREF=100PE2 loses DF election; elected as non-DF
9 Multi-AS ProceduresFor the tie-breaker, the loopback of the PE originating the MH NLRI is neededThis may be overwritten in a multi-AS environment (such as in option B)To preserve this, we use the Route Origin Extended Community
10 Multi-AS Procedures Local Pref is not passed across ASes Again, this is needed for tie-breakingTo solve this, the “VPLS Preference” field in the L2 info community is usedCompatibility between LP and VPLS Pref is described in the document
11 Multi-AS ProceduresFor both BGP and LDP signaling, there are three models for inter-AS operation“option A”: direct, back-to-back connections between ASes, with each AS treating the other as a CE device“option B”: ASBRs mediating the VPLS“option C”: multi-hop eBGP connections between RRs in each ASThis is completely analogous to IP VPNs
12 MAC FlushIf the designated forwarder (PE1) for a multi-homed CE goes down, remote PEs (PE3) should flush the MACs they learned from PE1Ideally, this is done implicitlyHowever, if PE3 is not upgraded, it may not flush; thus, in some cases, PE1 may have to send an explicit flush to the remote PEs
13 Next StepsPropose to adopt this as WG document?
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