OAM Elements Overview

IEEE 802.3ah defines OAM procedures for a single point-to-point Ethernet link. Ethernet OAM is a slow protocol with limited bandwidth requirements. The frame transmission rate is limited to a maximum of 10 frames per second. As a result, the impact of OAM on normal operations is negligible. However, when link monitoring is enabled, the CPU must poll error counters frequently. In this case, the required processor memory and usage are proportional to the number of interfaces that have to be polled.

Two major elements, the OAM client and the OAM sublayer, make up the Ethernet OAM. The OAM sublayer resides above the MAC layer and below the logical link control (LLC) layer. The OAM sublayer presents a MAC data interface to MAC clients and an OAM client interface to OAM clients. Figure 1 shows the OAM sublayer interfaces. For effective interoperation and enhanced collaboration with 802.3ad link aggregation, the OAM sublayer exists below the LAG bundle. The LAG bundle is present between the OAM sublayer and the MAC client.

Figure 1: OAM Sublayer Interfaces

The following sections describe the OAM elements:

• OAM Client
• OAM Sublayer