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New Member

Cisco 1841 Serial interface issue

Hi,

i have one problem in my client end router(cisco 1841).

In that they have leased line with 128 kbps.

But the link is down.

I take the router through console for troubleshooting.

while i check with the serial interface they show output like this.

Serial0/1/0 is down, line protocol is down

  Hardware is GT96K Serial

  Internet address is 192.168.35.125/30

  MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation PPP, LCP Closed, loopback not set

  Keepalive set (10 sec)

  CRC checking enabled

  Last input never, output 00:07:21, output hang never

  Last clearing of "show interface" counters 00:16:13

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     0 packets input, 0 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     27 packets output, 378 bytes, 0 underruns

     0 output errors, 0 collisions, 2 interface resets

     0 output buffer failures, 0 output buffers swapped out

     12 carrier transitions

     DCD=down  DSR=up  DTR=up  RTS=up  CTS=up

If DCD down means how to troubleshoot?

what is DCD??

can anyone tell me where is the issue.

6 REPLIES

Cisco 1841 Serial interface issue

Hi ,

DCD means carrier detect , so in your case there is no carrier.

The issue is the link. If the link is offered by a provider I would ask them to check the circuit.

Dan

New Member

Cisco 1841 Serial interface issue

if it is chance have any problem in serial cable or modem.

Re: Cisco 1841 Serial interface issue

Hi,

I do belive that the circuit is the problem. As far as I know:

    DSR is the terminal ready , in you case up , the router receives the modem ready , so the serial cable is not the problem

    DCD down means that the local modem cannot communicate with the other end modem.

Regards

Dan

New Member

Cisco 1841 Serial interface issue

Thanks for ur Information.

In case any modem or serial cable problem means which of the parameter to be down.

How to find that.

Re: Cisco 1841 Serial interface issue

Hi ,

DCD, CTS , DSR - are provided by the dce in your case the modem

DTR , RTS - are provided by the dte in your case the router.

If CTS and DSR are down and DTR and RTS are up ,this can be a modem or a cable problem.

Regards

Dan

New Member

Cisco 1841 Serial interface issue

Thanks for ur valuable information

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