Process Overview

The discovery process allows local Data Terminating Entity (DTE) to detect OAM on a remote DTE. Once OAM support is detected, both ends of the link exchange state and configuration information (such as mode, PDU size, loopback support, and so on). If both DTEs are satisfied with the settings, OAM is enabled on the link. However, the loss of a link or a failure to receive OAMPDUs for five seconds may cause the discovery process to start over again.

DTEs may be in either active or passive mode. Active mode DTEs instigate OAM communications and can issue queries and commands to a remote device. Passive mode DTEs generally wait for the peer device to instigate OAM communications and respond to, but do not instigate, commands and queries. Rules of what DTEs in active or passive mode can do are discussed in the following sections.