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Configuring the Cisco Discovery Protocol (CDP) with ESX/ESXi (1003885)

Details

ESX/ESXi 3.5, 4.x, and 5.x hosts have the ability to use the Cisco Discovery Protocol (CDP). The article describes configuring the host and provides an example configuration of a physical switch.

Solution

To configure CDP for a Standard vSwitch:
 
  1. Log in as root to the Service Console (via SSH, remote console, or physical console if connecting to ESX) or to management vmkernel port (if connecting to ESXi).

  2. Verify the current CDP setting for the desired virtual switch (vSwitch1, in this example):

    # esxcfg-vswitch -b vSwitch1

    You see an output similar to:
    listen

    The output of listen indicates CDP is configured to read CDP information from the physical switch if available.
    This is the default setting for ESX/ESXi 3.5, 4.x, and 5.x.

  3. Set the CDP status for a given virtual switch. Possible values here are down, listen, advertise, or both.

    Listen mode - The ESXi/ESX host detects and displays information about the associated Cisco switch port, but information about the vSwitch is not available to the Cisco switch administrator.

    Advertise mode - The ESXi/ESX host makes information about the vSwitch available to the Cisco switch administrator, but does not detect and displays information about the Cisco switch.

    Both mode - The ESXi/ESX host detects and displays information about the associated Cisco switch and makes information about the vSwitch available to the Cisco switch administrator.

    #  esxcfg-vswitch -B both vSwitch1

  4. Verify the new setting:

    # esxcfg-vswitch -b vSwitch1

    You see an output similar to:

    both

To configure CDP on a vNetwork Distributed Switches (vDS):
  1. Connect to vCenter Server using the vSphere Client.
  2. In the vCenter Server home page, click Networking.
  3. Right-click the vDS and click Edit Settings.
  4. Select Advanced under Properties.
  5. Using the checkbox and the dropdown, change the CDP settings.

The following is an example of configuring CDP for a Cisco 6500 physical switch:
  1. switch#
  2. switch# config terminal
  3. switch(config)# cdp run
  4. switch(config)# interface g1/1
  5. switch(config-if)# cdp enable
  6. switch# show cdp neighbors

    Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                    S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
    Device ID                        Local Intrfce   Holdtme   Capability  Platform         Port ID
    pa-tse-h24.pasl.vmware.com Gig   1/1             121       S           VMware ESXvmnic2
    pa-tse-h24.pasl.vmware.com Gig   1/2             121       S           VMware ESXvmnic3

Tags

CDP-info  configuring-cdp

Keywords

Cisco Discovery Protocol,CDP

Update History

05/11/2010 - Added ESX 4.0 to Products. 07/19/2010 - Added ESX 4.1 to Products. 01/27/2012 - Added ESXi 4.x and 5.0 to Products. 02/24/2012 - Added information on various CDP status modes

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