ProCurve Series 2300 and 2500 Switches Release Notes

198
Enhancements in Release F.02.02
CDP
CDP Operating Notes
Neighbor Maximum. The Series 2500 switches support up to 60 neighbors in the CDP Neighbors
table. Even though the switches offer only 12 or 24 ports, multiple CDP devices can be neighbors on
the same port if they are connected to the switch through a non-CDP device.
CDP Version Data. The Series 2500 switches use CDP-V1, but do not include IP prefix information,
which is a router function; not a switch application.
Port Trunking with CDP. Where a static or LACP trunk forms the link between the switch and
another CDP device, only one physical link in the trunk is used to transmit outbound CDP packets.
CDP-Capable Hubs. Some hubs are capable of running CDP, but also forward CDP packets as if the
hub itself were transparent to CDP. Such hubs will appear in the switch’s CDP Neighbor table and
will also maintain a CDP neighbor table similar to that for switches. For more information, refer to
the documentation provided for the specific hub.
Troubleshooting CDP Operation
The switch does not appear in the CDP Neighbors table of an adjacent CDP Device. This
may be due to any of the following:
■ Either the port connecting the switch to the adjacent device is not a member of an untagged
VLAN or any Untagged VLAN to which the port belongs does not have an IP address.
■ If there is more than one physical path between the switch and the other CDP device and
STP is running on the switch, then STP will block the redundant link(s). In this case, the
switch port on the remaining open link may not be a member of an untagged VLAN, or any
untagged VLANs to which the port belongs may not have an IP address.
■ The adjacent device’s CDP Neighbors table may be full. Refer to the documentation provided
for the adjacent CDP device to determine the table’s capacity, and then view the device’s
Neighbors table to determine whether it is full.
One or more CDP neighbors appear intermittently or not at all in the switch’s CDP
Neighbors table. This may be caused by more than 60 neighboring devices sending CDP packets to
the switch. Exceeding the 60-neighbor limit can occur, for example, where multiple neighbors are
connected to the switch through non-CDP devices such as many hubs.