Cisco Discovery Protocol (CDP) is a device discovery protocol that runs on all Cisco manufactured equipment. Each CDP enabled device sends periodic messages to a multicast address and also listens to the periodic messages sent by others in order to learn about neighboring devices and determine the status of these devices. See CDP Discovery.
1. Click Device Management > Discovery Protocols > CDP.
2. In the CDP Configuration area, enter the following information:
• Cisco Discovery Protocol (CDP): Control whether CDP will run on some, all, or none of Ethernet interfaces. Choose one of the following options:
– Enable All: Enable CDP on all ports supported by the security appliance.
– Disable All: Disable CDP on all ports.
– Per Port: Configure CDP on selective ports. CDP per port is recommended.
• CDP Timer: Enter the value of the time interval between two successive CDP packets sent by the security appliance. The default value is 60 seconds.
• CDP Hold Timer: The hold timer is the amount of time the information sent in the CDP packet should be cached by the security appliance that receives the CDP packet, after which the information is expired. The default value is 180 seconds.
Note: The Voice VLAN ID is a read-only field. You can configure the Voice VLAN on the Networking > VLAN page. For more information, see Configuring a VLAN, page 118.
3. In the Enable CDP area, specify which interfaces will run CDP. Click On to enable CDP on an interface, or click Off to disable CDP. This is required if you choose Per Port from the CDP drop-down list.