The MPLS WG Archive

[Curtis Villamizar <curtis@workhorse.fictitious.org>]

In message <4F9E13BCC53ED411A629009027E8D00C043336DA@msg001.dcat.ops.broadbando
ffice.net>, afarrel@movaz.com writes:
> Curtis,
> 
> I can't see any reason not to point out that a "give up and run away" type
> of timer can be overridden by other events.  The one you suggest
> (significant IGP change) could well be applicable to LDP, although I think
> it is less significant in CR-LDP.
> 
> I find...
> > There appears to be a school of thought where it is deemed beneficial
> > to keep forwarding state intact in only very limited cases such as
> > midnight controlled reload of routers for purposes such as software
> > upgrade.
> ...odd.  When a line card fails I should like to be able to swap to a new
> card and continue forwarding data with only a very short (10s of ms) break.
> Adrian
> --
> Adrian Farrel
> Movaz Networks Inc
> afarrel@movaz.com


When a line card fails, that line card will still be in the box for at
least a few minutes, more likely the better part of an hour, maybe
longer.  I don't know of any technician that can swap a line card in
10 msec.  I also don't know of any line card that can reboot in 10
msec.  When a line card fails if there is a TE tunnel and
local-protect on the TE tunnel, then the switch over is very fast.  If
it is LDP without TE or TE without local protect, the 10s of msec is
very likely not acheived.  That has absolutely nothing to do with
LDP-FT so I don't see why you brought it up.

At issue with LDP-FT is when the route processor fails and the line
card does not fail.  That is when the forwarding entries remain intact
and the LDP adjacency will be back shortly.  That is the case if the
route processor's software is reloaded for software upgrade.

As I said, I'll leave it up to the authors whether they want to make
any change to the document.  It sounds like you don't.  That's fine.

Curtis