T1's bouncing at regular intervals

[j.shrewsbury]

Greetings,

I have 2 circuits both with different start and end points that go down every 2hrs and 15 minutes, and then come back up for exactly 2 hours and 15 minutes. Then go back down. Any ideas?

[gschertz]

First are both of these circuits terminated on the same router anywhere? You say different start and end points so these circuits are totaly isolated from each other?

Are the circuits carryed by the same provider?

Do these circuits cross multiple cariers?

what modules are terminating the T1's?

router modle? IOS version?

Chech the routers for errors on the T1 cards.

Varify the linecode and framing from the provider, or providers.

I have never seen such a consistant drop on a T1, my first instenct would be to look at the carier, or a UPS issue.

Gene

[j.shrewsbury]

The first T1 is going from 3745 with external Adtran TSU -> 3725 with integrated T1 card V2.

The second is going from 3745 with integrate 2 port T1 card -> 3725 with integrated T1 card V2.

Totally separate circuits, 4 different cities. Both are using the same carriers. However, there are other circuits attached to all 4 routers that are not bouncing. 3 are running code 12.3.8 the 3745 with external Tsu is running 12.2.13

[jdewing]

These issues are always the strange ones and range from weird things like janitors unplugging things to vacuum to backup power recycling. I would open a ticket with both carriers and have them get the local loop provider involved to determine if there is a wiring issue.

Another thing you might want to try, if you have another router, is to move one T1 to another router and see if the behavior continues on the new router.

Don't change too many things at once, if you do and you fix it you won't know which change fixed the issue. Good luck!