The user must have the IGP shortcut or forwarding adjacency feature enabled in one or more IGP instances:
config>router>ospf(isis)>igp-shortcut
config>router>ospf(isis)>advertise-tunnel-link
The user can also disable specific MPLS LSPs from being used in IGP shortcut or forwarding adjacency by configuring the following:
config>router>mpls>lsp>no igp-shortcut
The user enables the weighted load balancing feature using the following router level command:
config>router>weighted-ecmp
When this command is enabled, packets of IGP, BGP, and static route prefixes resolved to a set of ECMP tunnel next-hops are sprayed proportionally to the weights configured for each MPLS LSP in the ECMP set.
The user can configure a weight for each LSP using the following command:
config>router>mpls>lsp>load-balancing-weight <32-bit-integer>
For an auto-LSP signaled via an LSP template, the weight is configured using the following command:
config>router>mpls>lsp-template>load-balancing-weight <32-bit-integer>
There is no default weight value for an LSP. If any LSP in the ECMP set of a prefix does not have a weight configured, the regular ECMP spraying for the prefix is performed. The user-entered weight is normalized to the closest integer value that represents the number of entries in the ingress prefix hash table assigned to the LSP for the purpose of spraying packets of all prefixes resolved to this LSP. The higher the normalized weight, the more entries are assigned to the LSP, and the more packets are sent to this LSP.