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BGP VPLS Multi-homing IETF 72. Bhupesh Kothari Kireeti Kompella Thomas Spencer. Status. RFC 4761, Section 3.5 describes multi-homing Details are missing on: Path selection Inter-AS operation This draft provides details on multi-homing operations for both intra and inter AS operations.
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BGP VPLS Multi-homingIETF 72 Bhupesh Kothari Kireeti Kompella Thomas Spencer
Status • RFC 4761, Section 3.5 describes multi-homing • Details are missing on: • Path selection • Inter-AS operation • This draft provides details on multi-homing operations for both intra and inter AS operations. • Details are in: draft-kompella-l2vpn-vpls-multihoming-01.txt
Basic Multi-homing CE device dual-homed to PE devices for redundancy BGP VPLS PE1 PE3 CE2 CE1 PE4 PE2 CE3 • Only one PE can be the designated forwarder • All VPLS PEs must elect the same designated forwarder • Path selection algorithm specifies rules to elect a designated forwarder • BGP path selection • VPLS path selection
Update in -01 version • Site Preference • Control of designated forwarder • Multi-homing in inter-AS operation • Methods described in RFC 4761: • Option (a): VPLS-to-VPLS Connections at the ASBRs • Multi-homing operations remain same • Option (b): EBGP Redistribution of VPLS Information between ASBRs • Change required on ASBR for multi-homing • Option (c): Multi-Hop EBGP Redistribution of VPLS Information between ASes • No VPLS state of any kind on ASBRs, thus no change on ASBRs
Site Preference • RFC 4761, Section 3.5 describes the use of BGP Local Preference to indicate a preference for a particular VE • BGP Local Preference is not carried across AS boundary • Version -01 proposes carrying VE preference in Layer 2 Info Extended Community • For backwards compatibility, Local Preference MUST be set to VE preference, if VE Preference is in use
Inter-AS: option (b) Operation CE2 VPLS PE using Local Pref • LP: Local Preference • VP: VE Preference • For backwards compatibility, ASBRs must do the following: • For VPLS advertisements to other ASes: LP to VP • For VPLS advertisements to PEs within the AS: VP to LP PE3 VP: 500 PE4 CE3 LP: 500 PE1 LP: 500 ASBR1 ASBR2 CE1 PE5 PE2 CE4 LP: 200 VP: 200 VP: 200