I have an IPT site of ten branches and the Head Quarter (HQ).The callmanagers were located in the HQ while srst were configured on the branch routers. After the deployment all the branches were able to call the HQ. After few weeks of deployment, it was only three branches that could call HQ. During troubleshooting, I noticed that (1) the phones in one of the branches can call themselves but not any other phone outside the branch (fall back to srst but could not reconnect to the callmanager again). (2)the remainning could neither register with the callmanager nor the srst server. Please, can anybody be of help. Thank you.