IntroductiontoIS-IS.ppt

Introduction to IS-IS Topics 1. IS-IS Overview 2. IS-IS Protocol Concepts 3. CLNP Addressing 4. IS-IS Database 5. MPLS TE Extensions for IS-IS 6. ISP Network Design Considerations 7. Configuration Examples 8. Basic Troubleshooting 9. Further Reading 1. IS-IS Overview IS-IS Overview The Intermediate Systems to Intermediate System Routing Protocol (IS-IS) was originally designed to route the ISO Connectionless Network Protocol (CLNP) . (ISO10589 or RFC 1142) Adapted for routing IP in addition to CLNP (RFC1195) as Integrated or Dual IS-IS IS-IS is a Link State Protocol similar to the Open Shortest Path First (OSPF). OSPF supports only IP IS-IS Overview IS-IS is an Interior Gateway Protocol (IGP) - for Intra-domain (AS) routing BGP provides inter-domain routing for IP networks ISO-IGRP is a Cisco proprietary routing protocol that can be used between CLNP domains IS-IS Overview 3 network layer protocols play together to deliver the ISO defined Connectionless Network Service - CLNP - IS-IS - ES- IS - End System to Intermediate System Protocol All 3 protocols independently go over layer 2 IS-IS Overview CLNP is the ISO equivalent of IP for datagram delivery services (ISO 8473, RFC 994) ES-IS is designed for routing between network hosts and routers (ISO9542, RFC 995). IS-IS for layer 3 routing between routers. (ISO 10589/RFC 1142). Integrated IS-IS (RFC 1195) works within the ISO CNLS framework even when used for routing only IP. IS-IS Overview End System Hellos (ESH) from Hosts and Intermediate System Hellos (ISH) from Routers used for ES-IS neighbor discovery Intermediate System to Intermediate Systems Hellos (IIH) are used for establishing IS-IS layer3 adjacencies ES-IS is somehow tied into IS-IS layer 3 adjacency discovery. ES-IS enabled automatically when IS-IS is configured on Ciscos 2. IS-IS Protocol Concepts Nodes Links Areas and Adjacencies Level-1 and level-2 routing IS-IS Protocol Concepts Network Nodes Hosts Level-1 Routers Level-2 R