1IETF69-Chicago-July 2007 Multi-Instance ISIS draft-previdi-isis-mi-mt-01.txt Stefano Previdi - Les Ginsberg - Mike Shand - Abhay Roy - Dave Ward - IETF-69 Chicago - July 26, 2007

222 IETF69-Chicago-July 2007 MI-ISIS Introduction ISIS extension (YAT) Allows separate ISIS instances to share nodes and links Allows routing and non-routign info to be conveyed and stored in separate LSPs separate flooding schemes separate LSDBs Full Topology isolation Ships in the night approach Mechanism used to mark packets with instance membership

333 IETF69-Chicago-July 2007 Update to first version Interoperability issues Broadcast Networks Use of dedicated multicast address for non-zero IID Per level address Hide MI-ISIS packets to non-MI capable routers MI routers MUST discard packets if: The destination multicast address is AllL1IS or AllL2IS and the PDU contains an IID TLV with non-zero value The destination multicast address is one of the two new addresses and the PDU contains an IID TLV with a zero value or has no IID TLV Note: still misbehaviour may happen if AllL1IS/ AllL2IS are improperly used for non-zero IID.

444 IETF69-Chicago-July 2007 Update to first version Interoperability issues - History Different choices have been evaluated 1.Different Mcast addresses. Gives isolation at little cost. Any implementation which does not properly filter mcast addresses today is already at risk for meltdown. 2.Ethernet II frame with new type. Implementations are not expecting IS-IS PDUs in anything other than format. This option requires major changes. 3.Combination of 1 and 2. Adds little if no benefit.

5IETF69-Chicago-July 2007 Multi-Instance ISIS draft-previdi-isis-mi-mt-01.txt Stefano Previdi - Les Ginsberg - Mike Shand - Abhay Roy - Dave Ward - IETF-69 Chicago - July 26, 2007