Hi,
I have recently implemented a new ASA5508-X replacing our old 5510. Our carrier delivers over a C2960-CG.
When I connect the ASA to the C2960-CG we get extremely slow speeds in a single direction. This changes as we change the speed/duplex. The scenarios are as follows. We have 100/100mbps DIA which on our old ASA is fine, and if we connect a laptop directly to the C2960-CG is fine.
1. Auto/Auto (both sides), both devices will negotiate at 1gbps/full duplex - Symptom is that the connection takes a long time to 'come up' and be usable, and we get 100mbps down and between 1 & 5mbps up.
2. ASA set to Full/100mbps - C2960-CG will go into half-duplex 100mb mode - upload will be 90mbps+ and download will be 15mbps.
I cannot explain why then its auto/auto and negotiates at full/1gpbs we see such poor performance upload. There are no interface errors, crc errors, frame errors etc, counters all sit at zero, the performance is just bad. What is worse is when we force the ASA side to 100mbps/full - the Auto/Auto ISP side shows half duplex for some reason. Does anyone know of a bug on the 9.8(2) version or anything else that might explain why we are seeing such an odd issue. We haven't changed the cabling or anything else except the ASA and we know the cabling works on a laptop as well so it doesnt 'appear' to be the C2960-CG or ISP side.
I have uploaded a show run and removed the acls, objects etc for brevity.
