CDP Issues

Answered Question
Nov 19th, 2007

Hey Guys, I have 2 x 2500 series routers and a 2950 series switch for my CCNA lab. I have entered the following on both routers:


cdp run

cdp enable (on e0 int)


If i run sh cdp neighbors from the switch it sees both routers


BUT...each router only sees the switch using cdp...not each other...


What could be the issue here? Both routers can ping/telnet each other


Thanks


Dean

Correct Answer by Kevin Dorrell about 9 years 3 months ago

There is no issue there. CDP shows only the directly connected neighbors, i.e. the device at the end of the cable. The switch is connected to both routers. The routers are directly connected to the switch, but not to each other.


The switch terminates the CDP - it does not pass it through.


The only exceptions are hubs and non-Cisco switches, which might pass CDP through transparently.


Kevin Dorrell

Luxembourg


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Correct Answer
Kevin Dorrell Mon, 11/19/2007 - 21:13

There is no issue there. CDP shows only the directly connected neighbors, i.e. the device at the end of the cable. The switch is connected to both routers. The routers are directly connected to the switch, but not to each other.


The switch terminates the CDP - it does not pass it through.


The only exceptions are hubs and non-Cisco switches, which might pass CDP through transparently.


Kevin Dorrell

Luxembourg


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