Protocols Supported

Historically, all routed protocols have had their own independent routing protocols: AppleTalk uses Routing Table Maintenance Protocol (RTMP), Novell uses Internetwork Packet Exchange (IPX) RIP, and IP uses RIP, IGRP, or OSPF. This is conceptually simple to understand, but it is often difficult to implement. Yet, it is necessary for network engineers to design and operate networks that support multiprotocol environments. Therefore, they need to be able to manage a mix of routing protocols.

OSPF supports only the TCP/IP protocol suite. Although TCP/IP is the most popular suite in use today, it is not the only one being used. The inability of a routing protocol to support other protocols can be a detriment to legacy networks or networks with unique routing needs.

When IS-IS was created, the protocol designers asked a significant question: Why can't one routing protocol handle multiple routed protocols? Consequently, integrated IS-IS was enhanced to support both OSI CLNP and TCP/IP networks. In addition, integrated IS-IS supports other network protocols; this can be of great benefit in a multiprotocol network.