Using Cisco Discovery Protocol
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Gathering Interface Traffic Information
The show cdp traffic command displays information about interface traf-
fic, including the number of CDP packets sent and received and the errors
with CDP.
The following output shows the show cdp traffic command used on
a router.
Router#sh cdp traffic
CDP counters:
Packets output: 13, Input: 8
Hdr syntax: 0, Chksum error: 0, Encaps failed: 0
No memory: 0, Invalid packet: 0, Fragmented: 0
Router#
This is not really the most important information you can gather from
a router, but it does show how many CDP packets are sent and received
on a device.
Gathering Port and Interface Information
The show cdp interface command (sh cdp inter for short) shows the
CDP status on router interfaces or switch ports.
As explained earlier, you can turn off CDP completely on a router by
using the no cdp run command. However, CDP can also be turned off per
interface with the no cdp enable command. You can enable a port with the
cdp
enable command. All ports and interfaces default to cdp enable.
On a router, the show cdp interface command shows information
about each interface using CDP, including the encapsulation on the line, the
timer, and the holdtime for each interface. Here is an example of this com-
mand's output on a router:
Router#sh cdp interface
Ethernet0 is up, line protocol is up
Encapsulation ARPA
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
Serial0 is administratively down, line protocol is down
Encapsulation HDLC
Sending CDP packets every 60 seconds
Holdtime is 180 seconds
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