We are testing out the IP Communicator for deployment to our outside sales staff. During our testing, we've found that some people can VPN (Microsoft PPTP VPN) into corporate from their homes and their CIPC works perfectly. However, for others, as soon as they place a call through the soft phone, their ping times go from <50ms to upwards of 1000ms. Obviously, this causes all sorts of delay. As soon as you disconnect the call, the ping times return back to normal. If we remove their router (Linksys WRT55AG, being one of them) from the config, it works perfectly.
I've tried turning off the SPI firewall within the router, as well as flashing it to the newest firmware. Nothing has helped.
Has anyone experienced this before?