VPRN auto-bind-tunnel using segment routing policy tunnels

About this task

When the resolution options associated with the auto-bind-tunnel configuration of VPRN service allow sr-policy tunnels from TTM, next-hop resolution of VPN-IPv4 and VPN-IPv6 routes that are imported into the VPRN and have one or more color-extended communities C1, C2, .. Cn (Cn = highest value) is based on the following rules.

Note: Contrary to section 8.8.2 of draft-filsfils-segment-routing-05, BGP only resolves a route with multiple color-extended communities to an SR policy using the color-extended community with the highest value.

Procedure

If the next hop is IPv6 and there is an SR policy in TTMv6 for which end-point = BGP next-hop address and color = Cn, then use this tunnel to resolve the BGP next hop.
Otherwise, if the next hop is IPv4 or IPv4-mapped-IPv6 and there is an SR policy in TTMv4 for which end-point = BGP next-hop address (or the IPv4 address extracted from the IPv4-mapped IPv6 BGP next-hop address in the case of VPN-IPv6 routes) and color = Cn, then use this tunnel to resolve the BGP next hop.
If no SR policy is found in the previous step but there is a non-SR policy tunnel in TTMv4 (next hop is IPv4 or IPv4-mapped-IPv6) or TTMv6 (next hop is IPv6) that is allowed by the resolution options and for which endpoint = BGP next-hop address, then use this tunnel to resolve the BGP next hop if it has the highest TTM preference.