No span sessions enabled. It definitely looks like a classic microburst output buffer overflow problem, but with a Sup720 and a 6748 module, I haven't seen this at this volume. Ticker volume has peeked recently, and that might contribute to it. It appears to start happening with more than 120Mbps and/or 12,000 pps output on the port. Other than moving to 10GB, I don't see any solutions. Given the 6748 buffer size, I'm surprised it's overrunning it at this volume.
---- Matthew Huff | 1 Manhattanville Rd Director of Operations | Purchase, NY 10577 OTA Management LLC | Phone: 914-460-4039 aim: matthewbhuff | Fax: 914-460-4139 > -----Original Message----- > From: Dale W. Carder [mailto:[email protected]] > Sent: Monday, December 12, 2011 10:10 AM > To: Matthew Huff > Cc: 'cisco-nsp ([email protected])' > Subject: Re: [c-nsp] Weird Multicast microburst amplification issue > > Do you have any span sessions enabled? > > Dale > > Thus spake Matthew Huff ([email protected]) on Fri, Dec 09, 2011 at > 01:48:35PM -0500: > > We have a multicast data stream (real-time ticker data) that by its > nature is very bursty. > > > > When we connect a source server via gigabit Ethernet to our > 6500/sup720 switch via a 6748 module and a destination server via > gigabit to the same or different module in the same switch, everything > works fine. If the destination server is on a different switch > connected by a layer3 10GB connection then we have significant output > drops on the Ethernet connected to the destination server. > > > > All switches are 6509/sup720 with 6748 line cards. QoS is disabled > globally. The servers are identical. The output drops only occur on the > Ethernet drop connected to the server. > > > > The only thing I can think is happening is that by routing the > traffic via the 10gb L3 interface, something is causing the traffic > burst to amplify, overrunning the output port. Has anyone seen this, > and does anyone know how to mitigate this? > > > > ---- > > Matthew Huff | 1 Manhattanville Rd > > Director of Operations | Purchase, NY 10577 > > OTA Management LLC | Phone: 914-460-4039 > > aim: matthewbhuff | Fax: 914-460-4139 > > > > _______________________________________________ > > cisco-nsp mailing list [email protected] > > https://puck.nether.net/mailman/listinfo/cisco-nsp > > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
