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ATM 4/0 UP but subinterface 4/0.1 DOWN

Unanswered Question
May 15th, 2006
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HI all,

Here is a question about an ATM issue, I´m new working with this technology and I don´t know wheter or not this behaviour could be normal.

The thing is that the ATM module (in a 7304 box) is generating temperature alarms and works weired, because sometimes needs to me unplugged from the chassis in order to start working, but the subinterface 4/0.1 never goes UP. There are some PVCs created over this interface (all of them are in DOWN status). Could be a hardware problem?

Thanks a lot in advance.



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mheusinger Tue, 05/16/2006 - 02:23
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subinterfaces are created in software and thus are down when the hardware is down. Once the hardware is up (ATM 4/0) the subinterfaces come up (at least for a short period).

In ATM there is a protocol called ILMI, which allows the ATM switch and the Router to exchange status messages regarding the PVCs. It might be a configuration issue - wrong VPI/VCI - so the switch can only tell that the PVC is "deleted/unknown". The router will then place the sub-interface in down status. Also ILMI could be disabled on the switch.

You should be able to turn off ILMI and the interfaces should be up all the time (no keepalive).

So I would check the settings with my ISP first and then configure the router accordingly to exclude those config errors.

Hope this helps! Please rate all posts.

Regards, Martin


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