TenGigabitEthernet port going into err-disabled

Unanswered Question
May 19th, 2007

TenGigabitEthernet is flapping and automatic going to err-disable status. i have chnaged the cable and the xenpack and the port, the link testing is also done. still the issuse remains the same, the port flaps and goes into err-disable. Can somebody help me why the port is flapping .

I have this problem too.
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scottmac Sat, 05/19/2007 - 13:07

What kind of cable are you using?

How long is it?

Did you completely clean both ends before using it? How did you clean it?

Let us know

Scott

rajaajmer Sat, 05/19/2007 - 17:56

the cable is fiber. Long enough to make the connection. I am not sure , wht do u mean by clean. pls explain.

scottmac Sun, 05/20/2007 - 05:45

Not good enough information.

The fiber should be single-mode fiber, something like 9/125.

Length is important, especially if the fiber is too short. Imagine trying to listen to someone talking to you from two feet away with a 1000 watt audio amplifier ... it's painful, and you won't understand. After a while, you'll go deaf.

If your (single-mode) fiber cable is too short, the receiver is getting an extremely "loud" signal that will likely be distorted (i.e., receiving errors and not communicating) ... and it will go "deaf" after a while (receiver will burn out or de-sensitize).

To prevent that, you need in-line attenuation to bring the signal level down to a "comfortable" level for the receiver.

By knowing how much signal the transmitter puts out, and how much signal the receiver needs for accurate & reliable understanding, and factoring in how much attenuation you get from the length of fiber you are using, you get a number that you use to decide how much additional attenuation you'll need (or whether you need it or not).

You can get fixed attenuators (one value) or variable optical attenuators (VOAs) ... but chances are you'll need to reduce the signal somewhat (and soon, before the receiver is damaged).

By cleaning, I mean cleaning ... remove dirt, film, oils, scum, crap .... bad things from the place where the beam of light enters and exits the fiber.

Single mode fiber is 8.3 microns in diameter ... 1/10 the thickness of an average human hair ... it doesn't take much "stuff" to block or diffuse the signal and kill your connection.

There are special cleaning kits / materials generally used to clean the ends of the fiber .. it's fairly soft glass and scratches easily ... so don't lick it and rub it on your shirt to clean it.

So, again, how long is your fiber, what kind of fiber are you using, and are you using any in-line attenuation?

Most single-mode jumpers are canary yellow, many/most/all multi-mode jumpers are orange-colored.

If you don't tell us, we can't help.

Good Luck

Scott

Paolo Bevilacqua Sun, 05/20/2007 - 03:13

Hi,

Suggest that you try a physical loopback test, that is, connect a patch of fiber from TX to RX.

Note, if the xenpack is single mode / long haul, you will need to do this with an inline optical attenuator.

If the test above fails to bring up the interface, please seek advice from the TAC.

Hope this helps,please rate post if it does!

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