Problems with 2950

Unanswered Question
Feb 25th, 2008


a few days ago I updated my 2950 from IOS 120-5.3.WC.1 to 12.1-22-EA11.

Since then my infrastucture started to behave in bizarre way. The leds suddenly stop blinking and after a few seconds recover their normal status.

The switches are connected through a trunk to a cat 3550 (mz.121-6.EA1).

The 2950 trunk configuration is:

interface GigabitEthernet0/1

switchport mode trunk

The 3550 trun configuration is:

interface Port-channel1

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

snmp trap link-status

The topology is fully resilience to faults (clustered). Two 3550 with an etherchannel between them, several 2950 & 2960 connected to the 3550 and between them trough trunk links

The 2960 with IOS 12.2(25)SEE are running without problems.

Due to the extrange behavior I had to rearrange the boxes connected to 2950 to the 2960.

My topology is running pvst.

Any ideas?

I will appreciate any help

Best regards.

I have this problem too.
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pascal.coyles Mon, 02/25/2008 - 10:40


Can you explain a bit how your 2950 is connected exactly to your 3550? You say Port-channel1 (3550) <-> trunk (2950)? Shouldn't it be trunk<->trunk?



julupegon Mon, 02/25/2008 - 13:49

Hi Pascal,

let me outline my topology

3550 <--Etherchannel--> 3550

| | | |

| |trunk trunk| |

| | | |

| 2950-----trunk-----2950 |

| |

|trunk trunk|

| |

2960-------trunk-------- 2960

All the switches are clustered. Now currently the 2950 are turned off to avoid extrange behavior, as I commented before.

I forgot before, when the leds stop blinking the port on the 3550 turns off, turns orange and finally blinks green.

May be something related to ST, but when only the 2960 and the 3550 are running they operate normally.

Thanks in advance and best regards.

julupegon Tue, 02/26/2008 - 13:30

Hi Pascal again and sorry for yesterday's drawing.

Attached, you can find a file with to drawings. The first one represents my topology when the problem arised. Today I removed all the 2950 from the cluster and the new topology is the one represented by the second drawing. In this way we still have the problem without affecting the network. We have connected 6 test PCs to the 2950.

Best Regards.



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