Chapter 15: IP Policy-Based Forwarding Configuration Guide210 SmartSwitch Router User Reference ManualSetting Load Distribution for Next-Hop GatewaysYou can specify up to four next-hop gateways in an ip-policy statement. If you specifymore than one next-hop gateway, you can use the ip-policy set command to control howthe 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-policypermit statement sequentially. For example, the following command picks the nextgateway 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-hopgateways by periodically querying them with ICMP_ECHO_REQUESTS. Only gatewaysthat respond to these requests are used for forwarding packets. For example, the followingcommand checks the availability of next-hop gateways specified in the policy ‘p1’:Note: Some hosts may have disabled responding to ICMP_ECHO packets. Make sureeach next-hop gateway can respond to ICMP_ECHO packets before using thisoption.Applying an IP Policy to an InterfaceAfter 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 beingforwarded according to the IP policy. (See the SmartSwitch Router Command Line InterfaceReference 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 PacketsYou can apply an IP policy to locally-generated packets (that is, packets generated by theSSR). For example, the following command applies the IP policy ‘p2’ to locally-generatedpackets:ssr(config)# ip-policy p1 set load-policy round-robinssr(config)# ip-policy p1 set pinger onssr(config)# ip-policy p2 apply interface int2ssr(config)# ip-policy p2 apply local
