cdp ? in Frame Relay environment

[philth_123_2]

Hi,

I have set up a lab to look at F/R with a partial mesh and sub-interfaces.

I have 3 DTE routers connected to a Frame Switch. One Router named 'middle' has the sub-interfaces configured on it. The other 2 routers named 'Top' & 'Bottom' are just physical interfaces.

I used RIP to route the two networks between Top & Middle and Bottom & Middle respectively. The F/R side has gone well, however, CDP switched itself off on both of the physical interfaces on routers Top & Bottom !!!

Is there a good reason for this ?

To rectify this I have simply enabled cdp on both the serial interfaces.

Regards,

Phil.

[pkhatri]

Hi Phil,

CDP is disabled by default on (physical) serial interfaces configured for frame-relay encapsulation. That is also the case on multipoint frame-relay interfaces. That is standard IOS behaviour. I think it's due to the fact that these interface types do not inherently support multicast.

Hope that helps - pls rate the post if it does.

Paresh