Here's my show ver IOS version:
Cisco IOS Software, C2600 Software (C2600-ENTBASE-M), Version 12.3(11)T2, RELEASE SOFTWARE (fc1)
It's a Cisco 2621 router providing NAT between fa0/0 and fa0/1. The WAN connection is tested from a device alongside this router as being approx 40mbit. A speedtest of a device accessing the WAN via this NAT router shows almost exactly 20mbit.
Can anyone suggest what might be limiting throughput here?
Best Answer
It is your routers performance that limiting you. Here is a cisco's routers performance PDF
Your router throughput is roughly 12.80 Mbps.