This article provides a solution to the issue of RSVP auto-mesh LSP not coming up when a more specific route to the tunnel destination is already present in the routing table than the tunnel route created in the inet.3 table.

The RSVP auto-mesh LSP will not come up if a more specific route to the tunnel destination is already present in the routing table than the tunnel route created in the inet.3 table. In order for a local router to spawn the RSVP auto-mesh LSPs, there must be a labeled route to the IBGP next hop (the LSP's destination) in the inet.0 table.

For each destination network configured under dynamic tunnels, a route of protocol type TUNNEL (tunnel route) is added to inet.3.  This is a non-forwarding route. When the tunnel route is added to inet.3, any table using inet.3 as one of its resolution ribs will have this route in its resolution tree.

If the route resolution for a next hop of a route (trigger route) selects a tunnel route and the tunnel type is rsvp, the creation of a dynamic RSVP LSP is spawned for the protocol next hop with the parameters configured for the RSVP LSP.

If both the tunnel route (above destination network address) and the LDP route are pointing to the same /32 address, the RSVP auto-mesh LSPs will not be created.

If both the tunnel route and the LDP route point to the same tunnel destination (/32) address, RSVP auto-mesh LSPs cannot be established.

The following lab test shows both the working and non-working configurations and results.

Topology:

Non-working configuration:

With this configuration, the dynamic LSP is not created as both the tunnel route and LDP route are pointing to the same tunnel destination.

lab@R1# show routing-options
static {
    route 11.11.11.11/32 reject;
}
router-id 1.1.1.1;
dynamic-tunnels {
    tunnel-test {
        rsvp-te test1 {
            label-switched-path-template {
                default-template;
            }
            destination-networks {
                3.3.3.3/32;
                4.4.4.4/32;
            }
        }
    }
}


lab@R1# show protocols mpls
traffic-engineering bgp-igp-both-ribs;
label-switched-path dynamic-template {
    template;
}
interface all;

lab@R1# run show route 3.3.3.3

inet.0: 12 destinations, 15 routes (12 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3.3.3.3/32 *[LDP/9] 00:05:55, metric 1
> to 10.10.10.2 via ge-0/0/0.12, Push 299936
[OSPF/10] 00:05:55, metric 2
> to 10.10.10.2 via ge-0/0/0.12

inet.3: 3 destinations, 7 routes (3 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3.3.3.3/32 *[LDP/9] 00:05:55, metric 1
> to 10.10.10.2 via ge-0/0/0.12, Push 299936
[Tunnel/300] 00:00:09
Tunnel

lab@R1> show mpls lsp ingress
Ingress LSP: 0 sessions
Total 0 displayed, Up 0, Down 0

Working configuration:

When the configuration is modified as below, the dynamic LSPs will come up as both the tunnel route and LDP route are not pointing to the same tunnel destination.

lab@R1# show routing-options
static {
    route 11.11.11.11/32 reject;
}
router-id 1.1.1.1;
dynamic-tunnels {
    tunnel-test {
        rsvp-te test1 {
            label-switched-path-template {
                default-template;
            }
            destination-networks {
                3.3.3.0/24;      <<<
                4.4.4.0/24;      <<<
            }
        }
    }
}

lab@R1# run show route 3.3.3.3

inet.0: 12 destinations, 15 routes (12 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3.3.3.3/32 *[LDP/9] 00:04:33, metric 1
> to 10.10.10.2 via ge-0/0/0.12, Push 299936
[OSPF/10] 00:04:33, metric 2
> to 10.10.10.2 via ge-0/0/0.12

inet.3: 5 destinations, 7 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3.3.3.3/32 *[RSVP/7/3] 00:04:08, metric 2
> to 10.10.10.2 via ge-0/0/0.12, label-switched-path 3.3.3.3:dt-rsvp-tunnel-test
[LDP/9] 00:04:33, metric 1
> to 10.10.10.2 via ge-0/0/0.12, Push 299936


lab@R1# run show route 3.3.3.0

inet.3: 5 destinations, 7 routes (5 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

3.3.3.0/24 *[Tunnel/300] 00:00:49
Tunnel

lab@R1# run show mpls lsp ingress
Ingress LSP: 2 sessions
To From State Rt P ActivePath LSPname
3.3.3.3 1.1.1.1 Up 0 * 3.3.3.3:dt-rsvp-tunnel-test
4.4.4.4 1.1.1.1 Up 0 * 4.4.4.4:dt-rsvp-tunnel-test
Total 2 displayed, Up 2, Down 0