[15769] in North American Network Operators' Group
Re: IP over SONET considered harmful?
daemon@ATHENA.MIT.EDU (Joseph Malcolm)
Fri Mar 20 17:01:18 1998
Date: Fri, 20 Mar 1998 16:41:36 -0500 (EST)
From: Joseph Malcolm <jmalcolm@uraeus.com>
To: "Paul E. Erkkila" <pee@frontiernet.net>
Cc: yakov@cisco.com (Yakov Rekhter), alan@globalcenter.net, nanog@merit.edu
In-Reply-To: <199803202023.PAA60164@frontiernet.net>
Paul E. Erkkila writes:
> Without going to far into the traceroute source , would
> a solution to this problem be a modified traceroute that
> "understood" and could report Tag/MPLS "hops" as well as
> the normal method? There would need to be some way of
> identifying which devices were forwarding using Tag/Mpls
> and which were not, as well as getting and reporting
> the information. I think it falls into the same category of
> tracing cell forwarding in ATM without having access to the
> equipment doing the work.
Without getting into whether this is a good idea - I suspect many
service providers would disable such a capability - one of the nice
aspects of traceroute is that it uses the usual packet forwarding path
until the last hop. In other words, it's a little hard to break the
normal packet forwarding mechanism without breaking traceroute too.
This charcteristic would be hard to preserve with such a solution.
> Alan and I discussed the "knob" solution before, it seems
> to solve the problem, but under certain circumstances a packet
> could end up being forwarded forever because of (mis)configuration.
You do have to make sure that tunnels always move packets closer to
their destination, yes.
