In the upstream direction, the T-LDP peer and the RSVP endpoint can be different.
In the following example, Router A has Router ID 10.20.1.1 and loopback address 1.1.1.1. Router C has Router ID 10.20.1.3 and loopback address 3.3.3.3.
A--------------------------- C
10.20.1.1 10.20.1.3
1.1.1.1 3.3.3.3
In the upstream direction, SR OS can configure the T-LDP peer between 1.1.1.1 and 3.3.3.3 and also configure the RSVP LSP between Router IDs 10.20.1.1 and 10.20.1.3.
In the downstream direction, the RSVP LSP must terminate on the targeted peer for the FEC to get resolved.