NW Diagramfrom PC i can ping ISP on loop back 8.8.8.8 via site A, but when iShutdown F0/1 of SITE-A , i cannot ping ISP from PCs.Actually i want to switch traffic to SITE-B , if SITE-A's link is down.PCs can ping SITE-B ip Address 192.168.1.2 but can...