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New Member

Serial1/0:0 Protocol Down.

Router: 3600 Series
Flash: c3640-i-mz.122-29b.bin

6 Channelized T1/PRI ports

One of our T1 crashed do to rain storms. It's a wet pair that causes the drop. Which is not my concern at the moment.

What i am facing with is that the Router has to be rebooted in order to re-establish a connection.

I have done (shutdown and no shutdown ) on the serial interface and controller t1. I would think by doing this it would re-establish the connection but it does not. So the solution here is to reboot everytime a t1 crashes.

Is there a solution to this instead of rebooting the router?

In theory i should just shut down the interface and bring it back up and it should come up instead of rebooting.

Thanks in advanced for your help.

Jon.

9 REPLIES
VIP Super Bronze

Serial1/0:0 Protocol Down.

In this case and since you have done sh and no sh on the interface and controller, there isn't much to do but rebooting the router.  If this is the only port on this WIC, than you could also have a bad WIC and may need to replace it.  Get an outage window and reboot it.

Good Luck

HTH

New Member

Serial1/0:0 Protocol Down.

Thanks for your reply. I have done all and no real fix but a reboot.

Looking for a better solution.

Thanks

New Member

Serial1/0:0 Protocol Down.

Jonathan,

A couple of things to do is to take a look at the controller and the stats on that T1.

Just as you do a shut / no shut on the interface, you can do the same on controller t1 1/0

also do a sho controller t1 1/0 to get information on how it is communicating with the WAN.  there is a lot of data and stats that are in the controller show command.  specifically look at the err sec in each 15 minute interval.  ideally, there should be 0 errored seconds, so if there are any or lots, then you have a carrier issue or your port on the card was damaged during the same storm.

If you have a free T1 port, try moving your configuration to that port and see if the problem follows the line.

Unfortunately, with a router that old, you do not have many options for replacement parts.

Good Luck

New Member

Serial1/0:0 Protocol Down.

Thanks but i have done all of that already. I was looking for a solution on bringing the interface backup after the issue was fixed without having to reboot the router.

Looking for a better solution.

Thanks

New Member

Serial1/0:0 Protocol Down.

Hi Jonathan,

I've been having similar issues.

I was wondering if you ever resolved this issue?

and how did you figure out it was a wet pair?

Thanks

New Member

Re: Serial1/0:0 Protocol Down.

Fa Khan, to find the wet pair I did the following.

1) The interface only goes down during a storm.

2) Checked for errors on the line on each location.

a. From ISP to Location1

b. From ISP to Location2

By doing this we determined that the issue was on the wire of location 2 on the phone line of the carrier. The carrier then Repaired the wire.

For the serial to come up after the fix automatically, I issued the following command on the interfaces.

  1. serial restart-delay 0

We have had storms and link disconnects and have yet to restart the router for the interface to come back up.

Hope this helped you and let me know if you have any other questions.

Jonathan

Sent from Cisco Technical Support iPhone App

Hall of Fame Super Silver

Serial1/0:0 Protocol Down.

Jonathan

Thank you for posting back to the forum and indicating your progress with this issue. It may help other readers to know what you have done to resolve this issue.

HTH

Rick

New Member

Serial1/0:0 Protocol Down.

Thanks a lot Jonathan,

I am getting a protocol state down when it goes down. and only returns after a reboot, I had swapped out the equipment and cables.

I've noticed a separate line we have for Wifi and that goes down too.

Using all that information I got them to check for a wet pair.

New Member

Re: Serial1/0:0 Protocol Down.

You guys are welcome. Hope it helps you out.

Sent from Cisco Technical Support iPhone App

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