TOI Author :: Soumya S Acharya

Class Based Forwarding (CBF) provides a means for forwarding traffic through selected tunnels based on the traffic class of the incoming packet. Starting 4.32.2F CBF supports forwarding MPLS labeled traffic based on the EXP value in the incoming packet or the internal traffic class (TC) resolved from the parameters of the packet (e.g TC derived from EXP bits combined with port trust mode). Here, EXP bits refer to the Experimental bits in the MPLS header.

The advertise high-metrics feature, when enabled on a device, advertises it with the metric as maxLinkMetric-1 value (i.e. 16777214). This allows the router to be used as a last resort if no other path is available.

This feature helps in figuring out if there are multiple nodes in the network with the same System-ID. A non-unique node leads to the failure of all subsequent functions of the IS-IS protocol, like LSP origination (leading to LSP constant flooding issue), SPF calculation and so on.