Odd issue cropped up this afternoon.... I have a provider putting in a new service to replace an existing service (as I provisioned the new port last week I just had this feeling it would be an issue). I'm in a meeting and see a carrier switch go down wondering what the heck? Nobody knew if there was actually a tech on site doing work so I called the provider NOC and inquired. At the same time I'm logging into the upstream switch and checking the port and light being received (port xcvr show port 10). That port was not receiving light from the switch in question. Once I spoke with the NOC I learned that they had inadvertently created a loop on their equipment and I think it adversely affected our 3916. They removed it remotely (this is all heresay about not having someone on site and doing it remotely) Could a loop cause loss of light transmitted? Someone on site did reboot the switch, but I'm almost positive it was not during the time I was checking for light on the other end.