To configure this feature:
enable resolution to RSVP-TE or SR-TE tunnels in the auto-bind-tunnel context
enable ECMP in the auto-bind-tunnel context
enable class-forwarding in the vprn context
define at least one class forwarding policy in the mpls context, the FC to sets associations and the LSP to (policy, set) associations
The SR OS CBF implementation supports spraying of packets over a maximum of six forwarding sets of ECMP LSPs only when the system profile is profile-b that is supported on an FP4-based CPM. In any other case, the maximum number of forwarding sets of ECMP LSPs is four.
config
router
[no] mpls
class-forwarding-policy policy-name create
fc be forwarding-set set-id <1..6>
fc l2 forwarding-set set-id <1..6>
fc af forwarding-set set-id <1..6>
fc l1 forwarding-set set-id <1..6>
fc h2 forwarding-set set-id <1..6>
fc ef forwarding-set set-id <1..6>
fc h1 forwarding-set set-id <1..6>
fc nc forwarding-set set-id <1..6>
[no] default-set set-id <1..6>
All FCs are mapped to set 1 as soon as the policy is created. The user can make changes to the mapping of FCs as required. An FC that is not added to the class-forwarding policy, is always mapped to set 1. At most, an FC can be mapped to a single forwarding set. One or more FCs can be mapped to the same set. The user can indicate the initial default set by including the default-set option.
The default forwarding set is used to forward packets of any FC in cases where all LSPs of the forwarding set the FC maps to become operationally DOWN. The router uses the user-configured default set as the initial default set. Otherwise, the router selects the lowest numbered set as the default forwarding set in a class-forwarding policy. When the last LSP in a default forwarding set goes into an operationally DOWN state, the router designates the next lowest-numbered set as the new default forwarding set.
A mapping to a class-forwarding policy and set is added to the existing CBF configuration of an RSVP-TE or SR-TE LSP or to an LSP template. The following commands perform this function:
config>router>mpls>lsp>class-forwarding forward-set policy policy-name set set-id
config>router>mpls>lsp-template>class-forwarding forwarding-set policy policy-name set set-id
An MPLS LSP only maps to a single class-forwarding policy and forwarding set. Multiple LSPs can map to the same policy and set. If they form an ECMP set, from the IGP shortcut perspective, packets of the FCs mapped to this set are sprayed over these LSPs based on a modulo operation of the output of the hash routine on the headers of the packet and the number of LSPs in the set.