Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

7206 Router / PA-T3 / DS3 / Serial Interface Down Question

We had a brief outtage and a sh log showed this:

*Mar 9 22:57:43.349 UTC: %LINK-3-UPDOWN: Interface Serial1/0, changed state to down

*Mar 9 22:57:44.533 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to down

We are trying to figure out what caused the interface to change state to down. After it came back up, we yanked a cable out of the PA-T3 adapter, plugged it back in and looked at the log. The exact same message sequence was logged. What can we make of this? Assuming the cable and adapter is in good condition, will we get the same error if our provider has a hiccup? I was under the impression that the serial line status would stay 'up' regardless of cable status, but that is not the case. Any pointers greatly appreciated.

1 REPLY
Silver

Re: 7206 Router / PA-T3 / DS3 / Serial Interface Down Question

When your serial interface looses carrier detect your link will go down . When your router misses 3 keepalives over a serial line this will cause the line protocol to go down , You can have a condition if your router is still rx carrier detect but it misses 3 keepalives , this will give you an up/down condition.

What caused this , more than likely a problem with your local exchange carrier .

280
Views
0
Helpful
1
Replies