Bug in Catalyst 3550 IOS Release 12.1(20)EA1

[admin_2]

I have experienced problems when upgrading 3550's from IOS Release 12.1(19)EA1 to IOS Release 12.1(20)EA1. The problem appears when connecting, disconnecting or booting any device connected to the switch by using a FastEthernet interface. When I do this I lose connection on all other FastEthernet interfaces for about 20 seconds. The Gigabit interfaces are not affected. This problem was solved when downgrading the IOS level to 12.1(19)EA1.

Anyone sharing my experiences with this bug? I have never found any document on the cisco web pages which mentions this problem.

[tekha]

No problem, I just checked my 3550, however I am not running 12.1(20)EA1, I am running 12.1(20)EA1a, maybe that little "a" makes a whole lot of difference?

[milan.kulik]

I don't think so, AFAIK, the "a" release only fixed the SNMP vulnerability problem.

BUT there is an interesting bug CSCee39647 in 12.1(20)EA1 with following description:

"Customers may see all ports on a 3550 running RSTP block when another device

such as a PC is plugged in. This will result in a disconnect from the network

for 30 seconds while STP reconverges."

So if you are running RSTP, this might be what you are looking for.

Regards,

Milan