Auto MDI/MDI-X + conference rooms + bored == loop

[trey at arena.net (Trey Valenta)]

I had a similar issue in which someone had accidentally looked a Cisco
VoIP phone back into the network. However, I found it strange how often
this would occur and eventually came across this field notice that might
apply to others on the list:

http://www.cisco.com/en/US/ts/fn/610/fn61863.html

Problem Description
        Disconnecting power from a locally powered Cisco IP Phone
        connected to a non-Power Over Ethernet (POE) Cisco switch may
        expose the customer's network to loop back storms that
        destabalize the virtual local area network (VLAN). This exposure
        can be mitigated by configuring the switches with automatic loop
        detection and port recovery.

Notes indicate this normally applies onto to 10Mb connections, but that
there have been reported cases on a 100Mbit network when the VoIP phone
is connected to a "highly sensitive uplink switch".

Trey
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