1. Protocol Topology Support for IS-IS Kay Noguchi draft-ietf-noguchi-isis-protocol-topology-01.txt 56th IETF San Francisco, CA, USA March 18, 2003

2. Copyright © 2003 IP Infusion Inc. All Rights Reserved. Contents RFC 1195 Restrictions Goal New TLV and Sub-TLV Adjacency Formation LSP Encoding SPF Calculation Migration Mechanism

3. Copyright © 2003 IP Infusion Inc. All Rights Reserved. RFC 1195 Restrictions Every router MUST be capable of all network layer protocols that are present in an area. –Can’t mix IPv4 only and IPv6 only routers Protocol Support capability MUST be identical on all interfaces. –Node oriented protocol support capability

4. Copyright © 2003 IP Infusion Inc. All Rights Reserved. Goal IPv4 only, IPv6 only and IPv4/IPv6 dual routers can co-exist. –By maintaining different SPF trees for each network layer protocols. Different protocol support capability on each Interface –Interface oriented protocol support capability

5. Copyright © 2003 IP Infusion Inc. All Rights Reserved. New TLV and Sub-TLV Interface Protocols Supported TLV –Encoded in IS-IS Hello. –Convey interface oriented protocol support capability to neighboring routers. Protocols Supported Sub-TLV –Encoded in Extended IS-Reachability TLV. –Flood interface oriented protocol support capability in the area.

6. Copyright © 2003 IP Infusion Inc. All Rights Reserved. Adjacency Formation MUST drop IS-IS Hello which doesn’t contain Interface Protocols Supported TLV. –To avoid possible routing loop. Point-to-Point Interfaces –MUST NOT form an adjacency if at least one of the same protocol capability is not met with neighboring router. Broadcast Interfaces –MUST attempt to form an adjacency regardless of the neighbor’s protocol capability. No change in DIS election.

7. Copyright © 2003 IP Infusion Inc. All Rights Reserved. LSP Encoding Use Protocols Supported Sub-TLV. Point-to-Point Interfaces –ANDing local and remote side of protocol support capability. Broadcast Interfaces –Regular LSP Local side of protocol support capability –Pseudo-Node LSP Remote side of protocol support capability

8. Copyright © 2003 IP Infusion Inc. All Rights Reserved. SPF Calculation SPF MUST be calculated separately for each network layer protocol. New Protocol Supported Sub-TLV MUST be used instead of old Protocols Supported TLV. –Reverse protocol support check is not “MUST” because pseudo-node LSP also contains Protocol Supported Sub-TLV.

9. Copyright © 2003 IP Infusion Inc. All Rights Reserved. Migration Mechanism 1) Start to advertise new TLV and Sub- TLV in addition to the old TLV. 2) Change adjacency formation and SPF calculation based on this draft. 3) Stop to advertise old TLV. 4) Change interface protocol support capability appropriately.

10. Copyright © 2003 IP Infusion Inc. All Rights Reserved. Questions?

11. Questions to M-ISIS Non M-ISIS IPv4 router and M-ISIS IPv6 router. –How to make adjacency? Non M-ISIS IPv4/IPv6 dual router and M-ISIS IPv4/IPv6 dual router. –Possible routing loop? IPv6 Reachability TLV and MT Reachable IPv6 Prefixs(M-ISIS). –Do we need both?