On Thu, May 31, 2007 at 05:27:24PM -0400, Scott Dunn wrote: > Hi > > We are seeing 2-4% packet loss on a 60Mbps link with 3725 when traffic > reaches about 35-40Mbps (based 30s load interval) (FYI the circuit has > been tested multiple times and is clean). I suspect that the traffic > is bursting to 60Mbps for short period and causing the loss.
Easy to verify. Configure a MQC policy with a policer with a conform action to transmit and an exceed action to transmit. Then watch for matches in the exceed line of 'sh policy-map interface <blah>'. If you see them you are bursting. Also, you would be seeing drops in the 'sh int <blah>' on output drops if you are bursting, overrunning the tx side line rate, and filling up the outputqueue. > > The Cisco command interpreter seems to indicate that the buffers need > tuning as I'm getting lots of failures vs hits for the larger buffers. > > VeryBig buffers, 4520 bytes (total 10, permanent 10, peak 13 @ 1w6d): > 10 in free list (0 min, 100 max allowed) > 84 hits, 685 misses, 11 trims, 11 created > 685 failures (0 no memory) > Large buffers, 5024 bytes (total 1, permanent 0, peak 4 @ 1w4d): > 1 in free list (0 min, 10 max allowed) > 14 hits, 671 misses, 131 trims, 132 created > 671 failures (0 no memory) > Huge buffers, 18024 bytes (total 1, permanent 0, peak 3 @ 1w4d): > 1 in free list (0 min, 4 max allowed) > 11 hits, 660 misses, 128 trims, 129 created > 660 failures (0 no memory) No they don't. And you shouldn't be hitting the system buffers for transit traffic anyway. Those buffers are only for process switched traffic. > > I don't have any experience playing with buffer sizes and was hoping > for some insight before experimenting, > > Thanks > > Scott > _______________________________________________ > 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/
