On Wed, Mar 9, 2011 at 1:46 PM, virendra rode <virendra.rode@outages.org> wrote:
Hi -
On 03/09/2011 11:21 AM, Jonathan Lassoff wrote:
We've been observing a small about of intermittent packet loss to/from AT&T and Level3 here in the San Francisco Bay Area this morning. In examining the situation, it seems like a evenly-spaced dropping of packets to certain IPs.
------------------- We experienced similar issue last week off our level3 connection for a specific /21 customer block. After further troubleshooting we decided to re-route our /21 to the other provider where packet loss issue went away. We are still scratching our heads over this issue.
Hrm. That's been my solution for this type of problem as well: just temporarily switch providers in both directions. This can be a little tricker if course if you're not a directly-downstream customer of the affected transit AS. I've been able to identify this problem by running mtr or traceroute simultaneously to several (at least 16+) IPs that are adjacent in a remote network and seeing different source IPs coming back for the ICMP type 11/code 0 (TTL Exceeded in transit) responses, and correlating loss to some subset of those IPs. Of course control plane policing or loaded CPUs on remote routers can confound these numbers. I feel like MTR does this especially well. Hope that helps. Good luck. Enjoy your routers.