Chapter 31 Configuring Ip Unicast Routing - Cisco Catalyst 3550 series Software Configuration Manual

Chapter 31 Configuring IP Unicast Routing
Distance-vector protocols supported by the Catalyst 3550 switch are Routing Information Protocol
(RIP), which uses a single distance metric (cost) to determine the best path; Interior Gateway Routing
Protocol (IGRP), which uses a series of metrics; and Border Gateway Protocol (BGP), which adds a path
vector mechanism. The switch also supports the Open Shortest Path First (OSPF) link-state protocol and
Enhanced IGRP (EIGRP), which adds some link-state routing features to traditional IGRP to improve
efficiency.
The SMI supports only default routing, static routing, and RIP. All other routing protocols require the
Note
EMI on your switch.
Steps for Configuring Routing
By default, IP routing is disabled on the Catalyst 3550 switch, and you must enable it before routing can
take place. For detailed IP routing configuration information, refer to the Cisco IOS IP and IP Routing
Configuration Guide for Release 12.1.
In the following procedures, the specified interface must be one of these Layer 3 interfaces:
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Note A Layer 3 switch can have an IP address assigned to each routed port and SVI. The number of routed
ports and SVIs that you can configure is not limited by software. However, the interrelationship between
this number and the number and volume of features being implemented might have an impact on CPU
utilization because of hardware limitations. For more information about feature combinations, see the
"Optimizing System Resources for User-Selected Features" section on page
All Layer 3 interfaces must have IP addresses assigned to them. See the
Network Interfaces" section on page
Configuring routing consists of several main procedures:
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A routed port: a physical port configured as a Layer 3 port by using the no switchport interface
configuration command.
A switch virtual interface (SVI): a VLAN interface created by using the interface vlan vlan_id
global configuration command and by default a Layer 3 interface.
An EtherChannel port channel in Layer 3 mode: a port-channel logical interface created by using
the interface port-channel port-channel-number global configuration command and binding the
Ethernet interface into the channel group. For more information, see the
EtherChannels" section on page
To support VLAN interfaces, create and configure VLANs on the switch, and assign VLAN
membership to Layer 2 interfaces. For more information, see
Configure Layer 3 interfaces.
Enable IP routing on the switch.
Assign IP addresses to the Layer 3 interfaces.
Enable selected routing protocols on the switch.
Configure routing protocol parameters (optional).
30-11.
31-5.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Steps for Configuring Routing
"Configuring Layer 3
7-27.
"Assigning IP Addresses to
Chapter 12, "Configuring VLANs."
31-3