Question about DS3 maintenance


Our upstream performed some scheduled maintenance early this morning
during the 1am PDT hour. The circuit was down a grand total of about
three minutes or so. The circuit came back up, but then went back down
ten minutes later, staying down for a while. All it took was a simple
interface bounce to bring this serial DS3 back online.

The questions I have are are as follows:

1. What would cause an otherwise normally-functioning circuit to drop
like this? This assumes normally-functioning equipment at both ends.

2. What would cause it to not recover, again assuming everything on
both sides is in otherwise working order? Keep-alives on our interface
appear to be set at their default of 10 seconds.

3. Are there any ways to effectively troubleshoot this issue while it's

4. Are there any steps we can take to prevent this from happening again?

If anyone needs more details, please hit me off-list then I'll summarize
if anyone's interested.

In the meantime, I will put mechanisms in place so we can catch issues
like this sooner so we can act sooner.

Thanks in advance!