I can only Monday morning quarterback from here but I would put the C3 at the bottom of the list of possible reasons for jitter. The C3 is a reasonably high-speed CPU, gigabit switch but I bet the cisco routers could not come close to processing...
Are you routing on the C3? IPsec itself adds delay because it requires CPU cycles on the router. (unless you running some sort off offload.) Are you giving your voice packets priority in the IPSec queue?
On the C3 you are able to assign pri...
