Hi mohammed

His problem with line protocol so when line protocol is down there problem with mismatch config only like (encapsulation, duplex, port settings etc.,)

So Mr. CM Leug plz once cross check your configurations at both ends should be same.

Dear Sir,

Thank you fro your input. The root problem is the cable issue. We re-connect the cable the interface is up again. thanks for your value input.

Best regards

CM Leung

Hi,

After checking the cables please do check the speed, as speed mismatch causes the link to no longer function. (Speed mismatch happens only if statically misconfigured on both ends), while duplex mismatch results in performance-related issues rather than resulting in no connectivity.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

Hi Scott,

A wrong cable will make your serial "down", not up. His problem is the protocol is down which is related to duplex/speed or port configuration (access or trunk and encapsulation).

We've seen instances where the wrong flavor of cable has caused an Up/Down...it might have been an old switch or combination of old/new, I don't recall.

Agreed that "Protocol Down" is probably a bad encaps ... but it's almost certainly not a speed / duplex thing.

Hi Scott,

Yes, you're right. I just made simulation test and you are correct. Thanks for the info.