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Root Bridge can't operate without Ethernet


I thought I had done this successfully before in an older version, so I think I may have a firmware problem.

With 3 BR352 running 12.01T, if I set the root to turn off the Ethernet port (or unplug it) it immediately loses the two non-root bridges. Restore Ethernet, and the wireless clients reassociate. (Yes, I used the serial console.)

The purpose of dropping the Ethernet link is to troubleshoot what I suspect to be a broadcast problem opriginating with the 10Mbps-only Half-Duplex-only AUI port on a C2500 that the root BR352 is connected to.

An alternative answer would be to keep the traffic from one non-root, which is destined for the other non-root, off the Ethernet port of the root.

Any help, paranoia, guidance or firmware bug insight would be appreciated.

Matthew Wheeler

Chief Wireless Architect

Blue Modal, Inc



In newer firmware there is a new feature

On the Ethernet hardware page you will see

Loss of backbone connectivity action The default is repeater.

If you set this to none then the non roots should stay associated and will should be able to test this

Hey if you think you have a broadcast problem on the ethernet side the best way is to get a sniffer trace

I saw that. I took 'repeater' to mean 'keep passing wireless traffic', but it sounds like maybe it's the passive repeater mode, leaving the other two without a root?

I've had half a dozen people tell the customer they need a Sniffer, there's just the problem of getting them to pay...


that. I took 'repeater' to mean 'keep passing wireless traffic'


It will go in AP repeater mode meaning that it will NOT pass any traffic through the ethernet interface. Just the same as if you configured an AP as a repeater.

The idea being that it can then associate to another root bridge and give you some fail over protection in the event of the ethernet interface going down.

Of course this configuration does not make a lot of sense if you only have 1 root bridge within radio range. But you do stop the the down stream bridges passing traffic to a black hole so it depends on how you want to manage your network.

Not as good as sniffer, but at least can see most of the packet in text format.

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