3745 VPN performance stats

[tech]

In the below link in Table 3-3 are the stats for the 3745 with the AIM-HPII module.

http://www.cisco.com/application/pdf/en/us/guest/netsol/ns142/c649/ccmigration_09186a00801e12ca.pdf

43 Active tunnels, 11.4 Mbps, at 50% CPU with IPSec/GRE

In another link, http://www.cisco.com/en/US/products/hw/routers/ps282/products_data_sheet09186a0080088750.html#wp40682,

the stats for the 3745 with the AIM-HPII Plus module at 1400 byte packets is:

2000 tunnels at 180 Mbps, no CPU % specified and without IPSec/GRE specified.

My question is - Does GRE and small packet size actually cause this massive of a decrease in total tunnels and throughput? Are there any case studies that specify stats on the 3745 with the AIM-HPII Plus module with IPSec/GRE?

Thanks,

RJ

[didyap]

IPSec and GRE are sure to consume a lot of resources. If the packet size is small, there will be more overheads in constructing the headers for IPSec and GRE. May be this is causing the degrade in throughput.