The MPLS WG Archive

[Ping Pan <pingpan@juniper.net>]

Ravi,

Ravi Shekhar wrote:
> 
> >
> > See, the LSP-ping proposal works, because it is based on the assumption:
> > the only working path from egress to ingress is the control path itself.
> > It is simple (no extra signaling other than adding one object) and
> > backward compatible (no change to the network LSR's).
> 
>   If by backward compatible you mean that intermediate LSRs do not have
>   to implement LSP-ping, then I agree.

Yes.

>   But is that really such a big win in the long run? 

Yes.

> If we are tracing LSP to an
>   LSR(which could be one of these inetwork LSRs) and if we dont recieve a
>   response from it, it could either be because LSP is down or the LSR does not
>   implement LSP-ping.

In the draft, it said, "... Before initiating the liveliness test, the
user must make sure that both ingress and egress LSR can support the
LSR-ping."

>  How do you know to distinguish between these two?
>   And if you cant, then indirectly it implies that LSP-ping be implemented
>   on all such routers and I think practically thats what will end up happening.
>   Whichever ping mechanism is used, we will end up having to support it on all
>   the routers.
> 

Now you start to scare me. :-) This is up to the network operators. 

- Ping