Application support

SR-TE IGP shortcuts can be used in the following applications.

1. family=ipv4 resolves IPv4 prefixes in RTM for the following:

   • IGP routes

   • indirect next hop of static routes

   • BGP next hop of BGP routes

   • LDP IPv4 prefix FEC

2. family=ipv6 resolves IPv6 prefixes in RTM for the following:

   • IGP routes

   • indirect next hop of static routes

   • BGP next hop of BGP routes

3. When an LDP IPv4 FEC prefix is resolved to one or more SR-TE LSPs, then the following applications can resolve to LDP in TTM:

   • L2 service FECs

   • BGP next hop of VPN IPv4/IPv6 prefixes

   • BGP next hop of EVPN routes

   • BGP next hop of IPv4 prefixes

   • BGP next hop of IPv6 prefixes (6PE)

   • IGP IPv4 routes (ldp-shortcut feature)

   • indirect next hop of IPv4 static routes

4. When an LDP IPv4 FEC prefix is resolved to one or more SR-TE LSPs, then the following applications cannot resolve to LDP in TTM:

   • next hop of BGP LU routes

     Note: Next hops of BGP LU routes cannot resolve to LDP in TTM because SR OS supports three levels of hierarchy in the data path and, because SR-TE LSP is a hierarchical LSP already, this makes the BGP-over-LDP-over-SRTE a 4-level hierarchy. BGP keeps these BGP-LU routes unresolved.