Cisco Discovery Protocol (CDP) network information

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

This article provides steps to view Cisco Discovery Protocol (CDP) information.

Resolution

CDP is used to share information about other directly-connected Cisco networking equipment, such as upstream physical switches. CDP allows ESX and ESXi administrators to determine which Cisco switch port is connected to a given vSwitch. When CDP is enabled for a particular vSwitch, properties of the Cisco switch, such as device ID, software version, and timeout, may be viewed from the vSphere Client. This information is useful when troubleshooting network connectivity issues related to VLAN tagging methods on virtual and physical port settings.

Note: For CDP information to be available, ESX hosts must be configured to listen for CDP information and connected devices must be advertising CDP information. If CDP information is not available, confirm that CDP is enabled on the ESX virtual switch and physical switch. For more information, see Configuring Cisco Discovery Protocol (CDP) with ESXi on DVS.

From the GUI CDP can be viewed under the Physical adapters section and selecting CDP.

 

Setting up CDP on a Standard Switch

We can also find CDP information by running this command from CLI:

# esxcfg-info | less

Search for the specific vmnic# (in this example vmnic0 ) to find the CDP information.

Example output:

|----Name........................................vmnic0
|----PCI Bus.....................................3
|----PCI Slot....................................0
|----PCI function................................0
|----MAC Address.................................xx:xx:xx:xx:xx:xx
|----Virtual MAC Address.........................xx:xx:xx:xx:xx:xy
|----Driver......................................bnx2
|----Network Hint................................0 <IpAddress>
|----MTU.........................................1500
|----Configured Speed............................1000
|----Actual Speed................................1000
|----Configured Duplex...........................1
|----Actual Duplex...............................1
|----Link Up.....................................true
|----enabled.....................................true
|----Wake on LAN supported ......................true
|----Wake on LAN enabled ........................true
|----Resource scheduler allowed ................true
|----Resource scheduler supported ...............true
|----CDP Network.................................true
\==+CDP Summary :
|----Cdp Version.............................2
|----Timeout.................................0
|----Time-to-live............................177
|----Samples.................................20131
|----Device Id...............................<ID>
|----Ip Address..............................<Ip Address>
|----Ip Prefix...............................0.0.0.0/0
|----Port Id.................................GigabitEthernet0/35
|----Capabilities............................40
|----Version.................................Cisco IOS Software,  Software
|----Platform................................cisco 
|----Vlan....................................1032
|----Duplex..................................true
|----MTU.....................................0
|----System Name.............................
|----System OID..............................
|----Mgmt Ip Address.........................<Ip Address>

 

 

Additional Information

For more information on the VMware vSphere PowerCLI, see the VMware PowerCLI.

To establish compatible virtual switch configuration, see VLAN configuration on virtual switches, physical switches, and virtual machines.