Configuring for Network Management Applications
CDP
Enabling or Disabling CDP Operation on Individual Ports. In the
factory-default configuration, the switch has all ports enabled and transmit-
ting CDP packets. Disabling CDP on a port prevents that port from sending
outbound CDP packets and causes it to drop inbound CDP packets without
recording their data in the CDP Neighbors table. Suppose, for example, that
switches “A” and “B” in figure
13-18 (below) are running CDP, and that port
A1 on switch “A” is connected to port B5 on switch “B”. If you disable CDP on
port A1 of switch “A”, then switch “B” will no longer receive CDP packets from
switch “A” and switch “A” will drop the CDP packets it receives from switch
“B”.
Switch "A"
CDP Enabled on Port A1
CDP Neighbor Table
Port | Data
------|------------------
A1 | Switch "B" data
Switch "B"
CDP Enabled on Port B5
CDP Neighbor Table
Port | Data
------|------------------
B5 | Switch "A" data
CDP Enabled on both
ends of the link between
"A" and "B".
Port A1
Port B5
Switch "A"
CDP Disabled on Port A1
CDP Neighbor Table
-Empty for port A1-
Switch "B"
CDP Enabled on Port B5
CDP Neighbor Table
- Empty for Port B5 -
CDP disabled on port A1
of switch "A" (but
enabled on port B5 of
switch "B".
Port A1
Port B5
Figure 13-18. Example of Disabling CDP on an Individual Port
(The switch "A" entry in the switch "B" CDP Neighbors table remains until the
cdp holdtime (time-to-live; set in switch "B") expires. Until then, the show cdp
neighbors
command continues to list switch "A" on port B5 of switch "B".)
Syntax: [no] cdp enable < [e] port-list >
For example, to disable CDP on port A1:
HPswitch(config) no cdp enable a1
13-35