Hi, We are using 2811 now, and I heard 2811 has up to 3mbps of vpn throughput. Now, we are planning to replace 2811 with 2951, but i would like to know, how is the vpn throughput on 2951? double than 2811 or more than that?
I fear that I cannot give you exact numbers as this depends on the traffic mix and the encryption parameters. In practice it is always best to test these things in real life.
One thing that I can tell you is that to get the maximum performance you need the securityk9 and hseck9 licenses for the routers. See http://www.cisco.com/en/US/prod/collateral/routers/ps10616/white_paper_c11_556985.html#wp9001382 for more information.
As you can read on that page without the hseck9 license the router will be limited to 85-Mbps of encrypted throughput, of course it depends on your situation if you can reach this value.
I hope this helps, if so please mark this question as 'answered'.