The following CLI objects enable the resolution over IGP IPv4 shortcuts of IPv4 and IPv6 prefixes within an ISIS instance, of IPv6 prefixes within an OSPFv3 instance, and of IPv4 prefixes within an OSPFv2 instance.
A:Reno 194# configure router isis
igp-shortcut
[no] shutdown
tunnel-next-hop
family {ipv4, ipv6}
resolution {any|disabled|filter|match-family-ip}
resolution-filter
[no] rsvp
exit
exit
exit
exit
A:Reno 194# configure router ospf
igp-shortcut
[no] shutdown
tunnel-next-hop
family {ipv4}
resolution {any|disabled|filter|match-family-ip}
resolution-filter
[no] rsvp
exit
exit
exit
exit
A:Reno 194# configure router ospf3#
igp-shortcut
[no] shutdown
tunnel-next-hop
family {ipv6}
resolution {any|disabled|filter}
resolution-filter
[no] rsvp
exit
exit
exit
exit
The new resolution node igp-shortcut is introduced to provide flexibility in the selection of the IP next hops or the tunnel types for each of the IPv4 and IPv6 prefix families.
When the IPv4 family option is enabled, the IS-IS or OSPF SPF includes the IPv4 IGP shortcuts in the IP reach calculation of IPv4 nodes and prefixes. RSVP-TE LSPs terminating on a node identified by its router ID can be used to reach IPv4 prefixes owned by this node or for which this node is the IPv4 next hop.
When the IPv6 family option is enabled, the IS-IS or OSPFv3 SPF includes the IPv4 IGP shortcuts in the IP reach calculation of IPv6 nodes and prefixes. RSVP-TE LSPs terminating on a node identified by its router ID can be used to reach IPv6 prefixes owned by this node or for which this node is the IPv6 next hop. The IPv6 option is supported in both ISIS MT=0 and MT=2.
The IS-IS or OSPFv3 IPv6 routes resolved to IPv4 IGP shortcuts are used to forward packets of IS-IS or OSPFv3 prefixes matching these routes but are also used to resolve the BGP next hop of BGP IPv6 prefixes, resolve the indirect next hop of static IPv6 routes, and forward CPM-originated IPv6 packets.
In the data path, a packet for an IPv6 prefix has a label stack that consists of the IPv6 Explicit-Null label value of 2 at the bottom of the label stack followed by the label of the IPv4 RSVP-TE LSP.
The following commands provide control of the use of an RSVP-TE LSP in IGP shortcuts:
config>router>mpls>lsp# [no] igp-shortcut lfa-protect | lfa-only]
config>router>mpls>lsp# igp-shortcut relative-metric offset
An LSP can be excluded from being used as an IGP shortcut for forwarding IPv4 and IPv6 prefixes, or the LSP in the LFA SPF can be used to protect the primary IP next hop of an IPv4 or IPv6 prefix.