[c-nsp] IP LFA in ring topology

Saku Ytti saku at ytti.fi
Fri Nov 30 07:15:57 EST 2012


On (2012-11-30 12:00 +0000), Phil Mayers wrote:

> I'm curious why everyone hates on LDP so much; is there some huge
> problem that it causes that I'm not aware of? Or is the objection
> conceptual.

I don't hate it. It just seems out-of-place, like I have body integrity
identity disorder and I want to cut that useless appendage away.

Only reason we have LDP is because our IGP labels are local scope. If
they'd be global scope, IGP would make perfect sense to them, then you
simply wouldn't need them. (And as seen earlier in thread, rLFA would be
trivial)
Today for most SPs either IGP + LDP is up, or nothing works. So vendors
implement IGP+LDP sync, to guarantee things work, which seems hack, why not
deliver them in same protocol as you need both at same time anyhow?

Saving one useless session will same some CPU, some memory, simplify
config, simply control-plane protection, simplify code-base. But LDP works
just fine, and when it comes to RSVP, I'm strongly in LDP camp.
In my view uou need RSVP if you don't have enough capacity in your best
path, I try to make sure we have. (Ok, I can name convergence applications
also where you can capitalize on RSVP).


-- 
  ++ytti


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