Cabletron Systems 9032578-05 manual Applying an IP Policy to an Interface

Chapter 15: IP Policy-Based Forwarding Configuration Guide

Setting Load Distribution for Next-Hop Gateways

You can specify up to four next-hop gateways in an ip-policystatement. If you specify more than one next-hop gateway, you can use the ip-policy set command to control how the load is distributed among them and to check the availability of the next-hop gateways.

By default, each new flow uses the first available next-hop gateway. You can use the ip- policy set command to cause flows to use all the next-hop gateways in the ip-policy permit statement sequentially. For example, the following command picks the next gateway in the list for each new flow for policy ‘p1’:

ssr(config)# ip-policy p1 set load-policy round-robin

The ip-policy set command can also be used to check the availability of next-hop gateways by periodically querying them with ICMP_ECHO_REQUESTS. Only gateways that respond to these requests are used for forwarding packets. For example, the following command checks the availability of next-hop gateways specified in the policy ‘p1’:

ssr(config)# ip-policy p1 set pinger on

Note: Some hosts may have disabled responding to ICMP_ECHO packets. Make sure each next-hop gateway can respond to ICMP_ECHO packets before using this option.

Applying an IP Policy to an Interface

After you define the IP policy, it must be applied to an inbound IP interface with the ip- policy apply command. Once the IP policy is applied to the interface, packets start being forwarded according to the IP policy. (See the SmartSwitch Router Command Line Interface Reference Manual for complete syntax information for the ip-policy apply command.)

For example, the following command applies the IP policy ‘p2’ to the interface ‘int2’:

ssr(config)# ip-policy p2 apply interface int2

Applying an IP Policy to Locally Generated Packets

You can apply an IP policy to locally-generated packets (that is, packets generated by the SSR). For example, the following command applies the IP policy ‘p2’ to locally-generated packets:

ssr(config)# ip-policy p2 apply local

210 SmartSwitch Router User Reference Manual