The MPLS WG Archive

["Doug Degan" <doug_degan@hotmail.com>]

hi jay, thanks for your answer.
I know that MP shouldn't propagate the path-tear message.
but how does he know upon a path-tear message arrival - that it belong to a
protected  LSP which this router acts as MP for it?
what exactly he checks in the path-tear message and in the  path-state to
know if to propagate it or not?

thanks.

----- Original Message -----
From: "Jay Karthik" <jkarthik@avici.com>
To: "Doug Degan" <doug_degan@hotmail.com>; "Ping Pan" <pingpan@juniper.net>
Cc: <mpls@UU.NET>
Sent: Monday, February 11, 2002 5:28 PM
Subject: Re: fast-reroute question


> At 04:35 PM 2/11/02 +0200, Doug Degan wrote:
> >ping, thanks for the quick answer but looks like I didn't understand it
or
> >wasn't clear enough in my question :
> >
> >I was refering to the time of failure. not to the time after failure when
> >the bypass is being used already.
> >
> >I assume bypass LSP is ready, and primary LSP is protected by it.
> >then a failure occures somewhere between the PLR and the MP.
> >the MP will probably get PATH-TEAR message because of it (also all the
> >routers between the failure and the MP will get it) but the MP shouldn't
> >send it downstream!!! because the lsp is not going to be teared from the
MP
> >to the Egress.
> >
> >to this problem I didn't find solution in the draft.
>
> Doug,
>
> As you said, the PathTear message will not be propagated downstream
> until the MP  has received tear-down from all merging LSPs and
> Section 3.2.2. (Procedures for the Merge Point) does describe it.
>
> >thanks again.
> >----- Original Message -----
> >From: "Ping Pan" <pingpan@juniper.net>
> >To: "Doug Degan" <doug_degan@hotmail.com>
> >Cc: <mpls@UU.NET>
> >Sent: Sunday, February 10, 2002 8:52 PM
> >Subject: Re: fast-reroute question
> >
> >
> > > Doug Degan wrote:
> > >
> > > > hi.
> > > >
> > > > I have another question regarding pan's draft in BYPASS method:
> > > >
> > > > 1) how does upstream routers act upon receiving of PATH TEAR
message?
> > > > there should be different activity between normal router and MP -
but
> > > > how does a router know he is active MP for a given LSP?
> > > >
> > > > if he does - he shouldn't tear it, but if he is just transit
router - he
> > > > should tear it!
> > > >
> > >
> > >
> > > When there is a network problem, the protected LSPs will use the
bypass
> > > LSP, and initiate Path Messages that will merge at MP. At this point,
> > > it's a bunch of RSVP sessions using SE. When you get a PathTear, just
> > > act according to what RSVP had defined.... kill the session and
> > > associated branches.
> > >
> > > - Ping
> > >
> > >
> > > >
> > > >
> > > > thanks in advance.
> > > >
> > > > doug.
> > > >
> > > >
> > > >
> > >
> > >
> > >
>
>