Hi, we are facing a problem at one of our branches with the ISPs, we have 2 lines from differnet ISPs when the main line is down , the backup line is supposed to take over in maximum time 3 min that is what is happing at all of our branches but not at that branch we are talking about the backup line does not take over. although, the 2 PVCs' status are active and the interfaces are up. In addition, the configuration at this site is the same as all branches and the ISPs have no incorrect cofiguration at thier sites.

Can anyone help?