CDP local or remote

[suneel gupta]

Hello Mr.lammle,
See the first line of CDP on page 283-
.....collect information about both loally attached and remote devices.
But in the rest of the chapter you told that CDP is used to find the devices that are locally attached(directly connected) and CDP packets aren't passed through a cisco switch. It's confusing.
Please clarify...

[lammle]

I am right with both sentences.

You can get information about remote devices, by first finding directly connected devices, then telnetting into those devices, then using CDP again to gather information about remote devices.

CDP only provides information about directly connected devices, but you can use this information to draw out your entire network.

Cheers!
Todd

[iworms]

Interestingly, CDP can be unreliable when you have devices from other vendors. My Linksys switch forwards CDP packets. I know because my two routers connect to the switch on Ethernet ports (so they're not directly attached on Ethernet ports), yet CDP shows each other as neighbors. This does not happen when using a Cisco switch.