North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: Operational issue: Packet loss at Pacbell NAP
Hi Dave and Kent, > > High bandwidth-delay product paths on a heavily loaded OC-3 to OC-3 > virtual > > circuit will strain the ATM switch buffers. If you can detect > regularly > > recurring losses on a high BDP path across an all-OC3 virtual > circuit, then > > look for buffer exhaustion on the OC3 interfaces. If no one at Pac > Bell > > knows what to do, tell them to look in the files in Fred Chang's > Network > > Engineering Group for Kent England's ATM NAP switch test plan and go > out and > > get some test gear that will stress an OC3 link in the lab. Mike > Rudik in > > the lab knows what to do to test for this. But my recollection was > that the > > BPX had enough buffers to run UBR over a full OC3. > > Nope. The problem is link congestion between SJC and SFO. Pacbell > was apparently not monitoring this. By rerouting some traffic, they > were able to shift the peers that it affected. It, with 100% > certainty, > is within the cloud that makes up the PB NAP. > > We've identified the facts that occured in this particular situation. The problem was definitely **not** due to link congestion as we have stats on the utilization of the OC3s. The rerouting which occured as a result of this problem has been corrected. We continue to monitor our OC3 links for any further problems. If you identify any additional issues, please feel free to submit a trouble ticket with our Network Data Center at 1-800-870-9007. Thanks, Steve Ellis Pacific Bell/SBC NAP Product Manager (925) 823-2722 (Phone)
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