Connectivity detection session creation method, network device, and system

A connectivity detection session creation method, wherein the method is applied to an Ethernet virtual private network (EVPN), the EVPN comprises a first network device and a second network device, and the method comprises:

• receiving, by the first network device, a creation message of a connectivity detection session from the second network device, wherein the creation message of the connectivity detection session carries an inclusive multicast route of the second network device and session information of the second network device;
• determining, by the first network device, that a local inclusive multicast routing table comprises the inclusive multicast route of the second network device;
• and
• creating, by the first network device, the connectivity detection session with the second network device based on the session information of the second network device.