IP Overview

IP Routing Protocols

Server load balancing allows a network administrator to define a virtual server to represent a group of real servers. For more information on this feature, see the “Configuring Server Load Balancing” chapter.

Mobile IP, which allows users to roam and maintain connectivity beyond their home subnet while consistently maintaining their IP address, is described in the “Configuring Mobile IP” chapter.

IP Routing Protocols

The Cisco implementation of each IP routing protocol is discussed at the beginning of the individual protocol chapters in this publication.

With any of the IP routing protocols, you must create the routing process, associate networks with the routing process, and customize the routing protocol for your particular network. You will need to perform some combination of the tasks in the respective chapters to configure one or more IP routing protocols.

Determining a Routing Process

Choosing a routing protocol is a complex task. When choosing a routing protocol, consider at least the following factors:

Internetwork size and complexity

Support for variable-length subnet masks (VLSMs). Enhanced Interior Gateway Routing Protocol (Enhanced IGRP), Intermediate System-to-Intermediate System (IS-IS), static routes, and Open Shortest Path First (OSPF) support VLSMs.

Internetwork traffic levels

Security needs

Reliability needs

Internetwork delay characteristics

Organizational policies

Organizational acceptance of change

The chapters in this publication describe the configuration tasks associated with each supported routing protocol or service. This publication does not provide in-depth information on how to choose routing protocols; you must choose routing protocols that best suit your needs.

Interior and Exterior Gateway Protocols

IP routing protocols are divided into two classes: Interior Gateway Protocols (IGPs) and Exterior Gateway Protocols (EGPs). The IGPs and EGPs that Cisco supports are listed in the following sections:

Interior Gateway Protocols

Exterior Gateway Protocols

Cisco IOS IP Configuration Guide

IPC-2

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Cisco Systems 78-11741-02 IP Routing Protocols, Determining a Routing Process, Interior and Exterior Gateway Protocols