I've got a Cisco 2811 (AdvIPServices 12.4(25e)) that is showing input errors on both its interfaces, all the errors are of the ignored type. The counter for ignore errors is not increasing continuously, which made me think it would be happening in line with traffic bursts, but there really isn't a large amount of traffic running through it at any time. Both the router interfaces are connected to a 4900 (IPBase 12.2(54)) series switch. The only things I can see are: There is a slight mismatch in duplex/speed negotiation settings, one side is set to auto/auto and one full/auto, however they have negotiated fine. There have been a few fallbacks on the interface buffers, and some trims in the public buffers. Any suggestions for things to look at? I will be correcting the duplex neg settings, and might try a buffer tune, but I don't think it will help.