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Setting load distribution for next-hop gateways, Applying an ip policy to an interface, Applying an ip policy to locally generated packets – Cabletron Systems SMARTSWITCH ROUTER 9032578-05 User Manual

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Chapter 15: IP Policy-Based Forwarding Configuration Guide

210

SmartSwitch Router User Reference Manual

Setting Load Distribution for Next-Hop Gateways

You can specify up to four next-hop gateways in an ip-policy statement. 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’:

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’:

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’:

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 p1 set load-policy round-robin

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

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

ssr(config)# ip-policy p2 apply local