The MPLS WG Archive

[Jay Karthik <jkarthik@avici.com>]

Doug,

The LSP ID in the sender_template object as well as the
Tunnel end point / Tunnel ID in the session object will be
matching for all the LSPs while the tunnel sender address
in the sender_template would vary in the path messages
that the MP receives.

The path tear message is also holding the session as well
as the sender_template object and the MP can figure out
whether or not the path tear message that it receives
belongs to a protected LSP.

-Jay


At 05:49 PM 2/11/02 +0200, Doug Degan wrote:
>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.
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> >
> >