Subject: RE: LSP-ping

From: Shahram Davari <[email-masked]>
Date: Tue, 17 Jul 2001 12:50:13 -0700

Ping,

What do you mean by multiple LSPs? if you mean multiple parallel LSPs, then the answer is what I said, that the ingress LSR should know which LSP is used as the reverse LSP for the ICMP-Echo. If by multiple LSPs you mean multiple hierarchical LSPs, it doesn't matter which one fails, if you don't receive the ICMP-ping through the LSP that is used to carry the ICMP-Echo (of the forward LSP), then the reverse path has effectively failed not the forward LSP.

-Shahram

> -----Original Message-----
> From: Ping Pan [mailto:[email-masked]]
> Sent: Tuesday, July 17, 2001 3:39 PM
> To: Shahram Davari
> Cc: [email-masked]'
> Subject: Re: LSP-ping
> 
> 
> Shahram Davari wrote:
> > 
> > >
> > > If the reserve path has multiple LSP's and one of them is
> > > down, how can
> > > you tell if the forwarding LSP (the one operators are
> > > interested in) is
> > > up or down?
> > >
> > 
> > The ingress LSR should know which LSP is the reverse LSP.
> > 
> 
> One more time, the reverse path can go through *many* LSP's. 
> One of them
> is dead in the middle of somewhere. How can the ingress know if the
> forwarding LSP is up or down base on ICMP ping's? The answer is it
> doesn't, and your scheme does not work!
>