In some deployment scenarios, for example to realize service function chaining, operators may want to perform a second action in addition to a traffic steering action. SR OS supports this behavior by configuring an extended action for a main action. This functionality is supported for Layer 3 traffic steering (that is, PBR) and specifically for the following main actions:
forward esi (Layer 3 version)
forward lsp
forward next-hop [indirect] [router]
forward next-hop interface
forward redirect-policy
forward router
forward vprn-target
The capability to specify an extended action is also supported in the case of PBR redundancy, for the following actions:
forward next-hop [indirect] router
forward vprn-target bgp-nh ip-address router service-name service-name [adv-prefix ip-address/mask] [lsp lsp-name]
The supported extended action is:
remark dscp dscp-name
The extended action is available in the following contexts:
config>filter>ip-filter>entry>action>extended-action
config>filter>ipv6-filter>entry>action>extended-action
Extended Action Restrictions
For forward lsp and for actions supporting redundancy, the extended action is not performed when the PBR target is down. Moreover, a filter policy containing an entry with the extended action remark dscp is blocked in the following cases:
if applied on ingress with the egress-pbr flag set
if applied on egress without the egress-pbr flag set
The latter case includes actions that are not supported on egress (and for which egress-pbr cannot be set).