Getting always Line protocol down for Serial

[ashok_boin]

Hi,

I am having 3660 series router with 4 sync and 40 sync/Async ports.My problem is say taking 5th module, in that for S5/0 interface, after connecting any link giving Serial5/0 up but always line protocol down. In the same module connecting to S5/4 is establishing connectivity i.e line protocol UP with the same setup.

Is it problem with hardware or anything else?How can i debug these serial interfaces?

Thanks in advance...

Regards...

Ashok.

[Frederic Vanderbecq]

Well, if the connection works on serial5/4 with an identical config as 5/0, it looks like the problem is hardware (broken port on 5/0). As a test, you could try to make a loopback connector, plug it into 5/0 and see if it comes UP. If not, it is definitely broken.

[ashok_boin]

Hello,

Loopback connector for Serial interface of Cisco?? Is it V.35 loopback connector or serial 60-pin loopback connector? If it is V.35, could you please send that V.35 loopback configuration.

Thanks in advance...

Regards..

Ashok.

[deilert]

You may also want to check the speed of the circuit , An async int will only support up to 128 Kb, If the circuit you are attaching to s5/0 , is over 128 kb , and it is an asyc int , the line protocol will not go up.