Cisco 1841 Routers - FA 0/0 and 0/1 Protocol DOWN when connecting back2back with another 1841

[sschumaher]

Hello guys, let me share with you one of the issues I have ran into during my course and I can't resolve on my own.

I am studying for my CNNA with a Cisco Lab kit I bought on Ebay and I ran into a issue which I can't figure out on how to resolve. I just hope it's not a fault that can't be repaired, based on the tests I did and I will list below it doesn't seem to be the case.

Issue happens on the 3x 1841 Routers I have - I have configured them multiple times on FA 0/0 and 0/1 and tried to connect them back to back to each other using a crossover cable but when I plug the cable there is no sign of connectivity (leds do NOT light up and there isn't any log on the command line either) - I have started the FA configs using auto for speed and duplex settings and then went to 100 and even 10 to lock down the port using these settings but still nothing happens. I have tried a SHUTDOWN followed by NO SHUT but still - the Status is UP but the Protocol remains DOWN.

What is intriguing me is that I cannot replicate the same issue when I connect the same routers to any of my switches using a cross over cable - that works fine - the routers FAST ETHERNET also works when I connect them to my laptop using a straight thru cable.

Another test I have done is connecting any of these routers using a straight tru cable on their Fast Ethernet to my Broadband wireless router/hub - when I do I get all the leds indicating connectivity on the FA ports and I can route the internet traffic to the routers.

These routers also have serial ports and they work also fine - issue ONLY happens using FA 0/0 or 0/1 between routers.

I have re-installed the IOS multiple times and played around with some of the settings I am familiar with but I think I might be missing something else?

I will paste below all the information on these 3 devices - any help or suggestion is appreciated.

RT1 - here FA0/0 is connected to my broadband router and FA0/1 is connected to FA0/1 on RT2 but as you can see no joy

Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.0.19 YES DHCP up up
FastEthernet0/1 10.0.0.1 YES manual up down
SchumaherRT1#

************************

RT1 FA0/0 info
RT1#sh inter fastEthernet 0/1
FastEthernet0/1 is up, line protocol is down
Hardware is Gt96k FE, address is 24b6.57a6.272f (bia 24b6.57a6.272f)
Internet address is 10.0.0.1/30
MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Auto-duplex, Auto Speed, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
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
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
1168 packets output, 75148 bytes, 0 underruns
0 output errors, 0 collisions, 7 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

***********************************************
RT2 state while plugged in to RT1
RT2#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES unset up down
FastEthernet0/1 10.0.0.2 YES manual up down
Serial0/0/0 unassigned YES unset administratively down down
Serial0/0/1 unassigned YES unset up up
*********************************************************

RT2 FA0/1 info

RT2#sh interfaces fastEthernet 0/1
FastEthernet0/1 is up, line protocol is down
Hardware is Gt96k FE, address is 0018.bad1.e2cd (bia 0018.bad1.e2cd)
Internet address is 10.0.0.2/30
MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Auto-duplex, Auto Speed, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:41:40, output hang never
Last clearing of "show interface" counters never
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
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
1156 packets output, 72883 bytes, 0 underruns
0 output errors, 0 collisions, 9 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

**********************************************************
RT3 - exatcly the same happens on this 3rd device.if I connect any FA to RT2 or 1 - currently RT3 is connected to RT2 via serial port.

If there is any logs I can enable or something I can try to run to test these ports another way might help me.

I forgot to add this before - routers are running with the following IOS image - c1841-ipbasek9-mz.150-1.M10.bin

Please advise.

Kind regards,
Seb

[sschumaher]

I forgot to mention the IOS image on these devices they are all running - c1841-ipbasek9-mz.150-1.M10.bin

[mlund]

Hi

It looks for me that You have mixed the concept of straight thru and cross over cable.

A router is an endhost, so is a computer.

If You connect an endhost to a switch, use straght thru cable.

If You connect two endhsots together, use cross over cable.

If You connect two switches together, use cross over cable

That said, most switches nowadays support auto detect for straight thru or cross over, also called "auto mdix".

/Mikael

[sschumaher]

Thank you very much for pointing this out, I will carry on further tests however I have used all the cables available on my Cisco Lab kit (including the green ones) and so far NOTHING - no joy.
The fact the same interfaces on these routers can communicate with other devices makes me thing it's NOT a fault - so it's either config or wrong cable, I will go back to the drawing board tonight and check further to rule out what you said.

I will report my findings here in case it helps anyone else.
Regards,
Seb

[Richard Burts · Accepted solution]

Seb

It sure sounds to me like it is a problem with the cable. If you have tried ALL of the cables that came with the kit then I suggest that you purchase a new Ethernet crossover cable and try it.

HTH

Rick

[sschumaher]

Of course, I will try that mate.

Thanks a lot.
regards,
Seb

[sschumaher]

That was it Richard, all the crossover cables that came with the kit are not working, I got a new crossover cable today and all works between the routers using both FA.

thank you again and have a nice weekend.

[Richard Burts · Accepted solution]

Seb

I am glad that my suggestion pointed you in the right direction and that new cross over cables did solve your problem. Thank you for marking this question as solved. This will help other readers in the forum to identify discussions that have helpful information. These forums are excellent places to learn about networking and I hope to see you continue to be active in the forum.

HTH

Rick

[sschumaher]

It's great to have this community and thanks again Rick - have a nice week!