Re: MPLS propagate-ttl question

On Sun, Nov 1, 2009 at 18:53, Ivan <ivanzghr_at_gmail.com> wrote:
> I have topology like this:
> R1 -- R3 -- R2 -- R4 -- R5
>
> where R2, R3 and R4 are LSR routers (R3 and R4 are PE, and R2 is P router),
> and R1 and R5 are customer routers.
> On routers R2, R3 and R4 I issued no mpls ip propagate-ttl
> forwardedcommand. How come that when I'm doing traceroute from R1 to
> R5 I still se
> info about MPLS labels in provider's network:
>
> R1#traceroute 5.5.5.5 source loopback 0
>
> Type escape sequence to abort.
> Tracing the route to 5.5.5.5
>
> B 1 10.1.13.3 4 msec 0 msec 4 msec
> B 2 10.1.45.4 [MPLS: Label 405 Exp 0] 0 msec 4 msec 0 msec
> B 3 10.1.45.5 28 msec * B 28 msec
>
> Is that normal behavior? Can we avoid provider's PE routers from traceroute
> output, and here 10.1.13.3 is R3, 10.1.45.4 is R4 (PE routers) and 10.1.45.5
> is CE.

What you are seeing is normal. You will always see ingress and egress
PE nodes. What you are hiding are P nodes. As you can see on the
output, R2 is hidden from the trace.

Try making a topology with several P routers - that's when this
becomes a little bit more obvious.

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