Direct connecting cisco routers

[ivstech]

I am trying to set up my lab with two Cisco routers. The serials are direct connected with RS449 cables (RS449MT and RS449FC). What happens is the interface comes up,up and then about 10 seconds later changes state to up, down.

I suspect this may be a cabling problem but I am not sure

 

[jeter]

are these cables your using a DTE and a DCE ? J.Fisher CCNA
Jeter@LasVegas.com

 

[ivstech]

One cable is DCE and the other cable is DTE.

I know this configuration will work with a DCE and DTE V.35 cable.

What makes me think it is a cabling problem is that both ends of the cable appear as DTE when you do a show interface. I have confirmed that I have a DCE and a DTE cable.

 

[talisker]

The router connected to the DCE side must have a clockrate set (global config command) or it won't work. Also, I recommend that you use HDLC encapsulation (on both interfaces) until you get them working. B-)

 

[KSM]

start clockrate from lowest and go up in DTE interface.
config " no keepalive" interface command in both routers.