Phased OSPF Link-State Database Synchronization draft-dimitri-ospf-phased-db-sync-00.txt Dimitri Papadimitriou Alcatel-Lucent IETF 79 – Beijing November 7-12, 2010

Motivation Opaque LSAs –OSPF extensibility: information contained in Opaque LSAs often used by application wishing to distribute information throughout OSPF domain (so called "non- IP routing information") –Standard OSPF flooding mechanisms used to distribute Opaque LSAs [RFC2370] –OSPF [RFC2328] mandates that neighbor is in Full state and the two routers are fully adjacent only when LSDB synchronization is completed Motivation: prevent delaying establishment of full adjacency b/w two routers (Full state) resulting from time needed to synchronize Opaque LSAs Occurs when #Opaque LSAs >> #non-Opaque LSAs

RFC RFC 2370 AB LSA Type 1|2|3|4|5|7 Opaque LSA Type 9|10| ,2,3,4,5,6,7,8 OSPF-Transport Instance LSA Type 1|2|3|4|5| Step 1: 1,2,3, Opaque LSA Type 9|10|11 Step 2: 1,2,3,4 hgfedcbahgfedcba gfebgfeb hgfedcbahgfedcba gfebgfeb hdcahdca hdcahdca LSDB Synchronization (current)

LSDB Synchronization (this draft) This draft Opaque LSA Type 9|10| Step 1: 1,3,4,8 LSA Type 1|2|3|4|5|7 Step 2: 2,5,6,7 hgfedcbahgfedcba hgfedcbahgfedcba This draft Opaque LSA Type 9|10| Step 1: 1,2,3,4 LSA Type 1|2|3|4|5|7 Step 2: 5,6,7,8 gfebgfeb hdcahdca gfebgfeb hdcahdca AB

Bottomline This draft reverts back to RFC 2328 the LSDB synchronization process that was extended by RFC 2370 –Remember RFC 2370 LSDB synchronization includes both non-Opaque and Opaque LSAs LSDB synch phasing achieved by logically segmenting LSDB sync process add "on top of" the LSDB synchronization process (per RFC 2328) a synchronization process dedicated to Opaque LSAs

LSDB Synchronization Process Compared to RFC 2370, Phased LSDB sync exchange process works as follows: Opaque LSAs are included in LSDB summary list sent to the neighbor iff i) The neighbor is Opaque capable (see [RFC2370]) ii) The neighbor has fully exchanged router-LSAs, network-LSAs, summary-LSAs (contained in the area structure), AS-external-LSAs (contained in the global structure), and Not-So-Stubby Area (NSSA) LSAs: Full state has been reached iii) Both local and neighbor router supports the phased LSDB synchronization

Per RFC 2328 ExStart, Exchange, Loading and Full states are defined per [RFC2328] Events NegotiationDone, ExchangeDone and LoadingDone are defined per [RFC2328] Reaching Full State, OSPF can perform all subsequent operations per [RFC 2328] including –computation of shortest-path tree for an area per [RFC2328] –computation of AS external routes per [RFC2328]

Phased Link-State Database (LSDB) Synchronization Process In case Full state is reached Start_O: LSDB contain Opaque LSA's AND capability successfully negotiated NExchange_O: –lists the content of its Opaque area LSDB (Type 9, 10, 11 LSA) in the neighbor DB summary list –router sends DD packets for these Opaque LSAs to the neighbor NExchangeDone_O: both routers have successfully transmitted a full sequence of DD packets Loading_O: LS Request packets sent to the neighbor asking for more recent Opaque LSAs discovered (but not yet received) in NExchange_O state LoadingDone_O: LS Updates have been received for all out-of- date portions of Opaque LSDB Full_O: Opaque LSA exchange completed

Backward Compatibility Phased LSDB synchronization process is backward compatible since –this draft extends the current process if and only if it is locally (see Section 4.2) and remotely supported (see Section 4.3) –If either of these conditions is not met LSDB synchronization falls back to the process currently specific per [RFC2370] This draft does not modify the LSDB process as specified in [RFC2328] Routers may be required to support both methods

Next Steps Interest in progressing this document at OSPF WG ?  Poll request for WG Document