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CDP over ISDN dialer interface


I need to configure CDP on BRI interface in ISDN network and to use it when the line is up from interesting traffic. I know that CDP doesn't work directly over BRI interface, but from Cisco documentation it seems that the workaround is to configure a dialer interface. In my implementation I have to use dialer profiles configuration (and not dialer-map); but I've got the error: CDP-EV encapsulation failed on dialer interface.

I've tried to use different IOS version without success. Is it possible to perform this kind of configuration?



Re: CDP over ISDN dialer interface

As per Cisco:

router#debug cdp events

CDP events debugging is on

*Mar 3 00:14:13: CDP-EV: Encapsulation on interface Dialer0 failed

In this example, the device did not send the CDP packet because the dialer map did not view the CDP packets as interesting traffic and did not bring up the line. Note that basic rate interfaces (BRIs) do not support CDP. Enhancement request CSCdu20683 has been opened against this. As a workaround, you can configure a dialer map to send the CDP packets. CDP is supported on dialer interfaces.

Debug CDP packets on the other end will show it arriving.

Hope it helps.


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