Troubleshooting networking is rather difficult if you can only connect to your ESX box via the console. Luckily I came across the instructions below
To extract CDP information using the ESX command line:
- Log in into ESX 3.5 via SSH as root.
Run the following command on ESX command line :
The following information is displayed:
Virtual switch port information
CDP information from the physical Cisco switch connecting to the ESX host .
Here is the link to the VMware KB Article.