Unnumbered PtP links (Was: Re: OSPF: incorrect path computation for v2.0.5+?)

[Ondrej Zajicek]

On Sat, May 23, 2020 at 05:49:35PM +0000, Joakim Tjernlund wrote:
> On Sat, 2020-05-23 at 18:19 +0200, Ondrej Zajicek wrote:
> > On Sat, May 23, 2020 at 03:55:16PM +0000, Joakim Tjernlund wrote:
> > > > > I would be glad to hear any comments to this idea or suggestions of other
> > > > > ideas how to solve it.
> > > 
> > > Thinking some more on this ..
> > > 
> > > The pos method depends only on your own Router LSA.
> > > If I recall correctly(mind you, this was a long time ago), the R-LSA only depends
> > > on your own interfaces wanting to use OSPF, you could always calculate your own R-LSA
> > > before starting any graceful restart(or so I hope) instead of relying on someone else's idea
> > > of you own R-LSA(it would be safer to only trust your self).
> > 
> > Well, the graceful restart is based on idea that your FIB (or Kernel)
> > still has previous routing table, so you should not use your current
> > adjacency state (as some adjacencies may not be yet established).
> > 
> > You need to parse your old R-LSA, wait until all adjacencies there
> > described are newly established, and then resume normal operation.
> 
> To be sure all adjacencies are there you would need to compare it against your own newly
> calculated R-LSA?  Once your are "happy", you can continue with you own R-LSA and still
> use the pos method.

Just checked that and router is supposed to do routing table calculations
even during graceful restart (but not use the routes for forwarding).
AFAIK, it is necessary just for vlinks - they are established only if the
other side is accessible in routing table computation.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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