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cisco port won't stay up - new to cisco ios

I have a Cisco 2900 XL that a coworker decided to move, in doing so, he unplugged everything and put the cables back in the wrong ports on accident. Now our trunk port fa0/24 on the Cisco 2900 won't stay up. It trunks to a Cisco 2600's fa0/1 port. Both ports have the same protocols and are setup as trunks.

When I plug a laptop into the cable leading to the Cisco 2600's 0/1 port, then the Cisco 2600's fa0/1 stays up (of course without communication since it's a trunk but at least it doesn't shut down) But as soon as I plug the cable from the Cisco 2600's fa0/1 gets plugged back to the Cisco 2900 fa0/24 of switch a, both ports go down. I don't see any port security on them either which was my first thought.

On the Cisco 2900 there are multiple VLANs on it as well. 4 ports to VLAN 50, 4 ports to VLAN 55, port fa0/1 goes to VLAN52, ports fa0/2-fa0/12 and fa0/23 to VLAN200, fa0/13-fa0/22 to VLAN52, fa0/24 trunked to the Cisco 2600.

Of course now that I am home, I can't remember the exact versions of IOS on the Cisco 2900 but I think it was 12.2 (or 12.0). Also the running-config shows that VLAN1 is down and VLAN 99 I can't remember if it's up or down but they aren't assigned to any specific ports.

This is my first time logging onto a Cisco device so I am certain I have far too vague of information and I have someone who will be able to fix it on Tuesday but I am hoping to see if there is something I can figure out because I don't like not being able to fix it :-)

If anyone has some ideas of obvious newbie mistakes, it would be appreciated. I know how to do the basic commands like conf t, int fa0/24, sho running-config ... stuff like that but I would think it would be something super obvious to an experienced person

Thanks!.

RPPreacher

Sounds like a network loop and STP is shutting the port down to avoid the loop

lruiz52

Check the cable, may need to use a cross-over cable.

Nayyar HH (CCIE RS)

Probably stp root guard on Fa024

To disable

conf t
int Fa0/24
no spanning-tree rootguard
end
wr mem

Fidelius

Please post config from both ports.
On 2900 do:
show run int fa 0/24

On 2600 do:
show run | beg interface FastEthernet 0/1
And copy part of config relevant to interfaces.

Regards!

Vanessa

ASKER

Here are the individual interfaces:
SwitchA#show int fa0/24
FastEthernet0/24 is down, line protocol is down
Hardware is Fast Ethernet, address is 00d0.5869.2598 (bia 00d0.5869.2598)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Auto-duplex , Auto Speed , 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:06:48, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1 packets input, 64 bytes
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast
0 input packets with dribble condition detected
1 packets output, 64 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
SwitchA#

SwitchB#show int fa0/1
FastEthernet0/1 is down, line protocol is down
Hardware is Fast Ethernet, address is 00d0.585a.dec1 (bia 00d0.585a.dec1)
Description: HelpDesk
MTU 1500 bytes, BW 100000 Kbit, DLY 100 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 2d20h, output 1d21h, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1267065596 packets input, 3726448003 bytes
Received 47355088 broadcasts, 0 runts, 0 giants, 0 throttles
7939 input errors, 7939 CRC, 0 frame, 12942 overrun, 12942 ignored
0 watchdog, 44648170 multicast
0 input packets with dribble condition detected
954339371 packets output, 2904521473 bytes, 0 underruns
0 output errors, 0 collisions, 9 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
SwitchB#

I have the full running configs and VLANs if needed too ...

Vanessa

ASKER

Forgot these if needed
!
interface FastEthernet0/24
switchport trunk encapsulation dot1q
switchport mode trunk
!
!
interface FastEthernet0/1
description SwitchA
switchport trunk encapsulation dot1q
switchport mode trunk
!

Fidelius

If I understand correctly, one device is Cisco 2900XL switch, and other is also a switch from your outputs above. In your initial question you said it is Cisco 2600 (2600 is router, not switch), so it would be great if you can clarify this.

With assumption that both devices are switches, and port Fa0/24 on SwitchA is connected to port Fa0/1 on SwitchB, you'll need crossover cable. As far as I know 2900XL doesn't have auto MDI/MDI-X ports, so to directly connect two switches which don't support MDI/MDI-X, you need crossover cable.

Regards!

Vanessa

ASKER

Actually they go through the patch panels ... one is in the main server room and the 2900 XL is at the helpdesk ... i am not 100% sure that the server room is a 2600 and can't get back to the office now to look ... they both are like devices but I am so new to routers and switches that I am probably saying them wrong ...just the person who shouldnt be fixing it lol ... luckily its not mission critical so it is a good learning tool.

SOLUTION

lruiz52

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Fidelius

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Vanessa

ASKER

I will try the crossover cable Tuesday morning... what is plugged in looks like a regular cable (but I haven't looked at the wires to confirm) and I have no idea what he took off of it but he was gung ho to rearrange at the helpdesk and had unplugged everything without labeling it ...

Thanks for all your patience with a newbie ... the rest of the holiday will be spent reading up on routers and switches so I don't feel so ignorant!

Vanessa

ASKER

Thanks ... he had removed a crossover as you said. Thanks for your assistance and patience!