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OSPF Based L1VPN Auto-Discovery ( draft-bryskin-l1vpn-ospf-auto-discovery-00.txt ). Igor Bryskin (Movaz Networks) : ibryskin@movaz.com. Lou Berger (LabN Consulting, LLC) : lberger@labn.net. Purpose of the document. To provide OSPF based L1VPN PE Auto-Discovery mechanism
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OSPF Based L1VPN Auto-Discovery(draft-bryskin-l1vpn-ospf-auto-discovery-00.txt) Igor Bryskin (Movaz Networks) : ibryskin@movaz.com Lou Berger (LabN Consulting, LLC) : lberger@labn.net
Purpose of the document • To provide OSPF based L1VPN PE Auto-Discovery mechanism • As described in Layer 1 VPN Basic Mode • Parallels BGP based L1VPN auto-discovery
Why IGP? • BGP approach also being defined • Requires all L1VPN edge nodes to support BGP • IGP alternative • Particularly applicable in networks where L1VPN edge nodes do not run BGP • Facilitates efficient and reliable distribution of routing and application information among IGP speakers • Maintains this information network-wide synchronized in conditions when some IGP speakers go in and out of service • Allows controlling the flooding scope • But, floods information to all IGP nodes, not just PEs • OSPF • This draft covers OSPF only • Parallel ISIS could be easily defined if there’s interest
Integration with Traffic Engineering • L1VPN autodiscovery mechanism based on IGP allows for integration with the Traffic Engineering • One example: L1VPN LSAs allow for the inclusion of TE attributes (of CE-PE links) • Such integration is NOT required by the draft
Opaque OSPF LSA (RFC2370) of a new opaque type is introduced for carrying L1VPN specific information L1VPN INFO TLV is introduced for encoding one entry of Port Information Table (PIT) L1VPN PE Address TLV is introduced to facilitate validation of L1VPN INFO advertisements originated outside of the area where they are used This mechanism is patterned after the way ASBR information (OSPF LSAs type 4) is used to validate AS external information (OSPF LSAs type 5) L1VPN LSA and its TLVs
L1VPN LSA format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS age | Options | LS Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opaque Type | Opaque ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Advertising Router | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS checksum | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN TLV(s) | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TE TLV | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L1VPN INFO TLV format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN TLV length | L1VPN TLV Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN Globally unique identifier | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PE TE Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | | L1VPN Auto-Discovery Information | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L1VPN PE Address TLV format 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN TLV length | L1VPN TLV Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PE TE Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
A PE originates AS-scope L1VPN LSAs carrying a single L1VPN INFO TLV for every locally configured PE-CE link. The LSA may also carry TE Link TLV with the link attributes A PE originates area-scope L1VPN LSA carrying L1VPN PE Address TLV for every PE address that was advertised by the PE in L1VPN INFO TLVs ABRs summorise received area-scope L1VPN LSAs (with L1VPN PE Address TLVs) and re-originate them into adjacent areas. ABRs withdraw their advertisements if/when the originator of a received LSA becomes unreachable Advertising rules
A PE that receives AS-scope L1VPN LSA with L1VPN INFO TLV uses such LSA for updating its local PIT if and only if the PE can find in its LSDB L1VPN LSA with L1VPN PE Address TLV matching the address specified in the received L1VPN INFO TLV Processing rules
The mechanism proposed in the draft could be used not just for L1VPN autodiscovery. One example: [GVPNs] proposes using E-BGP for publishing of membership information by PEs to CEs. Such service could be realized using PE-CE IGP In general, whatever could be done with BGP extensions could be also done with IGP extensions This document cover OSPF only, same approach can be applied to ISIS Do we need a generic mechanism for validation of AS-scope opaque advertisements (mesh membership, node capabilities, L1VPN, etc.)? We propose to make this draft a WG document Notes