[c-nsp] MPLS LDP Sync w/ ISIS over point to point Link

[Troy Boutso]

Hey

I've been rolling out new routers to various sites throughout our
organisation. And in doing so, I've been applying the "mpls ldp sync"
command under the "router isis" subsection.
This has been fine up until now. Because all other sites are running OSPF
and ISIS together (as we are in the process of migrating away from an OSPF
network to an ISIS based MPLS core network, etc).

With this new site, I only planed on only bringing up the isis adjacency as
it is a new site and no OSPF is required (because I don't need to migrate
anything off). However the ISIS adjacency won't come up because it doesn't
have an LDP session up yet. And the LDP session wont come up without the
IGP coming up.

This is some real chicken and egg stuff right here.

It has become quiet clear that all my other routers in production which
have LDP sessions are essentially relying on that OSPF adjacency to help
form the initial LDP session.
One day I plan to shut those down. Which could cause me big issues further
down the road.
I do have ldp session protection enabled ... but if a router was to reboot
and have no ospf to help form the initial LDP, then it seems my isis
adjecencie may never form. That is the worst case scenario


Getting back to my point ... If I remove the mpls ldp sync on both routers
the ISIS adjacency forms immediately. So this is definitely the culprit.
How on earth is this feature supposed to work in a production environment?
Am I missing something here?

Am I supposed to manually form ldp sessions (targeted) or something?
If anyone has experience with this, I'm all ears.

Kind Regards
Troy