Hi every one , Seriall S0 is do

[Guest_imported]

Hi every one ,

Seriall S0 is down & line protocol down.
Which layer is problem .
1.network
2.physical
3.transport
4.session.

I opted for physical . Any idea if i am wrong ??

 

[Taraporter]

You are correct. The output shows status for layer 1 and 2. Since network, transport and session are all above layer 2, physical is your only option. If the status said Serial S0 up and line protocol down, then you would have a layer 2 problem.

Tara

 

[drae73]

You are absolutely correct. With this being the case you have either an interface or cabling problem (physical layer). Great job!

 

[CCIEWANNABE]

Serial interfaces operate in pairs and normally there are CSU/DSU's between them along with the cable media.
A tip is to examine the various signals thru the use of the show interface command. Examine the output display.........
DCD, DSR, CTS are signals generated by a DCE
DTR and RTS are sugnals generated by a DTE
An Interface down and line protocol Down is a Phsical layer issue
in example:
DCD=up DSR=up DSR=down RIS=down CTS=up tells us the DTE router is down.

or in example;
DCD=down DSR=down DSR=up RIS=up CTS=down tells us that its a CSU/DSY or the media between the two routers