Simple Router to Router Link not working

[Mokhalil82]

Hi Guys

I am working on a lab at home and have got all my switching and firewall stuff working. I am trying to setup a simple connection from my router to the ISP router. Both are 2611xm routers. The protocol just does not come up. I have labbed just a basic router to router connection in Packet tracer with the same ip's and it comes up straight away

Is there something simple im missing here?

My port config on either side are 

Interface ser 0/0

ip address 60.139.240.17 255.255.255.240

duplex full

speed100
no shut

interface ser 0/0
 ip address 60.139.240.18 255.255.255.240

duplex full

speed100

no shut

I have also tried a serial cable between the 2 routers and same issue. Interface outputs are as follows

DR_Router(config-if)#do sh int ser 0/0
Serial0/0 is up, line protocol is down
  Hardware is PowerQUICC Serial
  Internet address is 60.139.240.17/28
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, loopback not set
  Keepalive set (10 sec)
  Last input never, output never, output hang never
  Last clearing of "show interface" counters 01:01:03
  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
     134 packets output, 3213 bytes, 0 underruns
     0 output errors, 0 collisions, 46 interface resets
     0 unknown protocol drops
     0 output buffer failures, 0 output buffers swapped out
     91 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

ISP_Router(config-if)#do sh int ser 0/0
Serial0/0 is up, line protocol is down
  Hardware is PowerQUICC Serial
  Internet address is 60.139.240.18/28
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, loopback not set
  Keepalive set (10 sec)
  Last input never, output never, output hang never
  Last clearing of "show interface" counters 00:41:58
  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
     39 packets output, 2130 bytes, 0 underruns
     0 output errors, 0 collisions, 14 interface resets
     0 output buffer failures, 0 output buffers swapped out
     22 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

Images

flash:c2600-advsecurityk9-mz.124-19b.bin

flash:c2600-advsecurityk9-mz.124-1a.bin

[Richard Burts · Accepted solution]

Can you tell us how these routers are connected physically? I am a bit puzzled at this statement in your post "I have also tried a serial cable between the 2 routers". If you are connecting serial interfaces what kind of cable are you using?

When a serial interface is up but the line protocol is down it is a sign that keepalives are not working. One common cause of this is a problem with clocking. Can you tell us what is providing clocking for this connection? In a lab environment I would frequently expect one of the routers to have a DCE interface and to be configured to provide clocking for the connection.

HTH

Rick

[Reza Sharifi · Accepted solution]

Hi,

If these interfaces are RJ45 than you need a T1 cross over cable to connect them back-to-back

If they are DB90 interfaces you need a DTE/DCE cable with clock rate command on the DCE side

clock rate 64000

HTH

[Mokhalil82]

Thanks guys, managed to get the link working, at working I have been working a lot with newer devices so they auto detect so even if you use a straight through cable a router to router connection works. So I was working on my home with older kit so no auto-detect so needed a cross-over.

The router have the serial interfaces so I managed to find a serial cross-over as all the rj45 cables I had were straight through's. I got mixed up with the DTE and DCE sides hence why it wouldn't come up.

Thanks you guys pointed me in the right direction

[Reza Sharifi]

Yes, that always happens when you work with older devices.  Not that many people still use the old serial interfaces any more (specially in the U.S) as these days most providers provide high speed Ethernet hand offs.  Also the price is so much lower that is not even worth getting a T1 or T3 anymore unless of course there is nothing else available and that is all you can get in your area. Good old days.

Glad to help

Good luck and thanks for the rating.

Reza

[Richard Burts]

I am glad that our responses were helpful in pointing you to the right direction. And glad that you did get it working. Thank you for using the rating system to mark this question as answered. This will help other readers in the forum to find threads that have helpful information.

HTH

Rick