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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: level3.net in Chicago - high packet loss?!?
On Tue, 6 Sep 2005 [email protected] wrote: > > On Tue, 6 Sep 2005, Christopher L. Morrow wrote: > > > On Tue, 6 Sep 2005, chip wrote: > > > > > On 9/6/05, Joe Maimon <[email protected]> wrote: > > > > > > > > > > > > If the hop(s) following the one you see loss for shows no loss, then > > > > disregard the loss for that hop, obviously whatever it is, it does not > > > > affect transit, which is what you really want to know. > > > > > > > > Is that correct? > > > > > > > This is one of the most misunderstood concepts in properly reading output > > > from a traceroute (mtr, visualtraceroute, whatever). Basically you are > > > seeing loss of packets destined directly *TO* that router, not THRU it. Most > > > > no... not destined TO the router, destined THROUGH the router that happen > > to TTL=0 ON that router. > > Very true. Most backbone kit on a tier 1 network is designed to switch I was really just pointing out that 'traceroute' or 'mtr' send packets with increasing TTL to show 'loss' or 'delay' from place to place, I wasn't trying to debate the every-changing reasons why backbone equipment might or might not answer 'ttl-expired' or 'unreachable' (or any 'exception traffic' really) in a 'timely' fashion. That issue changes with the wind/os/hardware/model.... :) nice to L3 sending in the answer police though :) Thanks! -Chris
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