Line Protocol on Serial Interface is not coming up

[netlife]

Hi,

I am connecting router on both the ends of an E1 link.
The setup is router-modem-----E1------modem-router.
My serial interface of the router(Cisco3640)is physically up but the line protocol is down on both the ends.
The E1 link is up and I am getting loop from the far end modem.On modem,I am getting Rx,CD but Tx is not detected.
Tx should come from router.

Please suggest what could be an issue.

Thanks.

 

[johnpoole]

strange terms, i'm stateside, so we play with e1, but the setup would be router, csu t1 csu router. your problem could be as simple as not having the connection rolled,, ie router a's transmit is connected to router b's transmit. layer one test clean but never "stands up".. i would test without the csu, in house using a hand made "e1" pin's 1 and 2 to pins 4 and 5, 4-5 to 1-2.. when is't possible i perfer to test with just my equiptment as end points

john poole
bellsouth business
columbia,sc

 

[jneiberger]

You say the physical layer is up, but are you receiving any frames at all? I would suspect that you're probably not receiving any frames but the link is physically up, from the routers perspective, because it is talking electrically to the modem.

It's not entirely relevant, but what layer two protocol are you using? What version of IOS?

 

[netlife]

Hi,

I found that AT & T has given a bidirectional loop and both of us are recieveing the loop.
As far as cabling is concern,the tx (Orange,Orange White---at RJ-45 Jack end) is connected to Rx of the ISP STM1 MUX.
I am getting framing error on both the ends.I have used ppp
encap on both the serial ports.

Thanks,
PV

 

[jneiberger]

Did you have AT&T drop the loop?