i have establised site-to-site vpn, Cisco Call Manager is in HQ, Location-1 & Location-2 are connected HQ via VPN, each locationz has Cisco IP Phone & it is pointing to the same Cisco Call Manager which means all calls are registered in the Cisco Call Manager in HQ. from location-1 i can ping HQ PC perfectly & on location-2 also i can ping HQ PC perfectly, on location-1 some times my IP phone doesn't work, it restarts, but at the same time location-2 ip phones doesn't restart even thought there is no VPN issuez on the both locationz, the moment when ever i hav problem in location-1 ip phone, i clear the vpn session peer ip address & it starts working, why is that so? if Cisco Call Manager has got any issuez, then it should affect the location-2 ip phonez also, but it doesn't, it affects only location-1 ip phones even thought there is no VPN problemz(pinging is perfect) on location-1. any help would be highly appreciated. this has become to regular practice.