Re: New router feature - icmp error source-interface [was: icmp rpf]
Chris, So, I'm wondering: What happens when you have a traceroute tool that shows you MPLS-lableled hops, too? :-) http://momo.lcs.mit.edu/traceroute/index.php The best (?) of both worls, but I digress... - ferg -- "Chris L. Morrow" <christopher.morrow@verizonbusiness.com> wrote: [snip] What's interesting is that today, in many networks, the usefulness of traceeroute has bee degraded by other non-ip issues (<cough>mpls</cough>) not in ALL cases, but certainly in many you are not seeing quite what you'd expect from the traceroute :( -- "Fergie", a.k.a. Paul Ferguson Engineering Architecture for the Internet fergdawg(at)netzero.net ferg's tech blog: http://fergdawg.blogspot.com/
On Tue, 26 Sep 2006, Fergie wrote:
Chris,
So, I'm wondering: What happens when you have a traceroute tool that shows you MPLS-lableled hops, too? :-)
:) depends on the network I guess... I'm not sure it's going to tell you anything about hops hidden by mpls lsp's that don't decrement ttl though...
On Tue, Sep 26, 2006 at 02:51:21AM +0000, Fergie wrote:
So, I'm wondering: What happens when you have a traceroute tool that shows you MPLS-lableled hops, too? :-)
http://momo.lcs.mit.edu/traceroute/index.php
The best (?) of both worls, but I digress...
That doesn't show any more or less data about the path, just some extra info about the label that is effectively useless to end users. If TTL decrement is not enabled, all of the IP hops are hidden by the tunnel, which is the point Chris was making. But that said, I personally think Cisco MPLS with TTL decrement enabled but returning the the same rtt as the penultimate hop for every IP hop inside the LSP has caused far more harm to every NOC ticket queue on the planet than just hiding the damn things. While we're asking for silly features, I can name a LOT of people who would pay good money for a dedicated ICMP generating processor on Cisco that doesn't spike every time BGP scanner runs. Silencing end users who have figured out how to work traceroute (or worse MTR) is worth its weight in gold. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)
participants (3)
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Chris L. Morrow -
Fergie -
Richard A Steenbergen