Port channel, CatOS, unidirectional links... the usual suspects

The Scenario:

Two 6500's. Three of the gig links between them configured as a port channel. All three are trunks. CatOS (grrrr...)

The issue

Users start complaining. I isolate the problem to this pair of cats and take a look. CPU at 100... interfaces dropping millions of packets...I look at the logs... HSRP is reporting dup addresses on a gob of segments.... lots of them... as many as you might find, say, on a trunk. Says I to myself: "I've got a loop between those cats." Upon investigation I find that *all three* of the links in the port channel are unidirectional. There we go. I move the channel to three different ports, different gbics, different fiber, blah blah... happy network, happy users,

The question?


I may be as thick as Randy Bushs' wallet, and I've been away from the catOS for some time, and I've never seen the like on a native, but I don't quite get this. It's highly improbable that all three of these interfaces (on three different line cards) went into this state. Could one single interface in UD mode cause the entire channel to do that? Bear in mind that I didn't just assume each of these links was UD, I saw all three in that state from the cons.

Anyone have a clue for me?

ps: I know, I know, udld.... only been on the job two months and I began my criticisms in the core. :)

p.p.s: by the way... hi everybody. :)

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