Risk and impact of enabling LLDP or CDP

Products

• VMware vSphere ESXi

Issue/Introduction

Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP) allow network devices to share information about their identity and configuration. See Switch Discovery Protocol for more information on support for switch discovery protocols in ESXi and the process for enabling them.

vSphere ESXi does not make configuration changes or act in response to CDP or LLDP information; it only displays it in vSphere Client for informational purposes. However, external network devices may respond to information present in CDP or LLDP data, and risks do exist due to a known issue in certain network cards.

Resolution

Enabling CDP or LLDP does not affect the behavior of ESXi virtual switches but may affect other network devices and third-party configuration solutions that interact with vSphere. Check with your network team or hardware vendor on potential impacts of enabling CDP or LLDP.

Certain network interface cards (NICs), such as the Intel X series and Broadcom NetXtreme series, have embedded LLDP agents that can cause unexpected behavior including a host disconnect. Please refer to the following knowledge base articles for important information about X7xx and NetXtreme-E network cards.

Hosts May Disconnect from vCenter or may not forward traffic when using a X710 or XL710 or X722 family card when LLDP is enabled

ESXi may lose management network connectivity or disconnect from vCenter when using a Broadcom NetXtreme-E network card