Hello, I am learning computer networking but am having a little trouble. I purchased 2 2610 routers, 2 4 a/s network modules, and 2 1ft serial DCE/DTE crossover cables. My problem; When I setup the interfaces on one router the status goes up and line prot goes up but after a few seconds the line prot goes down. On the second router, it stays down no matter what. I did a sho controllers and it is showing a v.35 cable (DTE and DCE). Any suggestions would be helpful.
Your configuration looks good. What stands out as being troublsome follows:
From the show int:
Router_DTE>show int ser1/1
Serial1/1 is up, line protocol is down
Last input never, output 00:00:09, output hang 00:04:19
Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the last fields exceeds 24, the number of days and hours is printed. If that field overflows, asterisks are printed.
This is also backed up from the show controllers for the same interface:
Router_DTE>show controllers ser1/1
CD2430 Slot 1, Port 1, Controller 0, Channel 1, Revision 19
Channel mode is synchronous serial
idb 0x815D0420, buffer size 1524, V.35 DTE cable
Transmitter hang count 450
I'm gonna guess that you may have a faulty module or cable.