Setting CDP Properties
CDP Overview
Similar to LLDP, CDP (Cisco Discovery Protocol) is a link layer protocol for directly connected neighbors to advertise themselves and their capabilities to each other. Unlike LLDP, CDP is a Cisco proprietary protocol.
CDP Configuration Workflow
The followings is sample workflow in configuring CDP on the switch. You can also find additional CDP configuration guidelines in the LLDP/CDP section.
See the Identifying Smartport Type section for a description of how CDP is used to identify devices for the Smartport feature.
The CDP Properties page enables entering CDP general parameters.
To enter CDP properties:
- Click Administration > Discovery - CDP > Properties. The CDP Properties page opens.
- Enter the parameters.
- CDP Status--Select to enable CDP on the switch.
- CDP Frames Handling--If CDP is not enabled, select the action to be taken if a packet that matches the selected criteria is received:
- CDP Voice VLAN Advertisement--Select to enable the switch to advertise the voice VLAN in CDP on all of the ports that are CDP enabled, and are member of the voice VLAN. The voice VLAN is configured in the Voice VLAN Properties page.
- CDP Mandatory TLVs Validation--If selected, incoming CDP packets not containing the mandatory TLVs are discarded and the invalid error counter is incremented.
- CDP Version--Select the version of CDP to use.
- CDP Hold Time--Amount of time that CDP packets are held before the packets are discarded, measured in multiples of the TLV Advertise Interval. For example, if the TLV Advertise Interval is 30 seconds, and the Hold Multiplier is 4, then the LLDP packets are discarded after 120 seconds. The following options are possible:
- CDP Transmission Rate--The rate in seconds at which CDP advertisement updates are sent. The following options are possible:
- Device ID Format--Select the format of the device ID (MAC address or serial number).
- Source Interface--IP address to be used in the TLV of the frames. The following options are possible:
- Interface--IF User Defined was selected for Source Interface, select the interface.
- Syslog Voice VLAN Mismatch--Check to send a SYSLOG message when a voice VLAN mismatch is detected. This means that the voice VLAN information in the incoming frame does not match what the local device is advertising.
- Syslog Native VLAN Mismatch--Check to send a SYSLOG message when a native VLAN mismatch is detected. This means that the native VLAN information in the incoming frame does not match what the local device is advertising.
- Syslog Duplex Mismatch--Check to send a SYSLOG message when duplex information is mismatched. This means that the duplex information in the incoming frame does not match what the local device is advertising.
- Click Apply. The LLDP properties are defined.