Tp-Link T2600G-28MPS (TL-SG3424P) Руководство пользователя онлайн [135/379] 174195

commonly used, and their codes are 0x00, 0x01, and 0x04. The three OAMPDUs are

described as follows.

Information OAMPDU:

Information OAMPDU is used for discovery. It transmits the state

information of an OAM entity (including local, remote, and organization-specific

information) to another OAM entity, and maintains OAM connection.

Event Notification OAMPDU: Event Notification OAMPDU is used for link monitoring. It is

sent as an alarm when a failure occurs to the link connecting the local OAM entity and a

remote OAM entity.

Loopback Control OAMPDU: Loopback Control OAMPDU is used to control the remote

client’s OAM remote loopback state. Its Data field consists of a remote loopback

command to enable or disable the OAM remote loopback, so that the local client can

enable/disable loopback on the remote OAM entity.



OAM Functions

As defined by IEEE 802.3 Clause 57,

Ethernet in the First Mile.,

OAM functions include Discovery,

Link Monitoring, Remote Failure Indication, and Remote Loopback.

Discovery

Discovery is the first phase of Ethernet OAM. During this phase, an OAM entity discovers other

OAM entities and establishes connections using Information OAMPDUs.

As for OAM connection, an OAM entity can operate in two modes: active and passive. Only the

active OAM entity can initiate an OAM connection process. The passive OAM entity waits and

responds to OAM connection establishment requests. Interconnected OAM entities notify the

peer of their OAM configuration information and the OAM capabilities of the local nodes to

support OAM by exchanging Information OAMPDUs, and then determine if OAM connections

can be established. Only when the settings concerning Loopback, link detecting, and link event

of the both side match can an OAM connection be established.

Figure 8-2 OAM Discovery

The difference between active OAM mode and passive OAM mode is shown as follows.

Item

Active OAM mode

Passive OAM mode

Initiating OAM Discovery

Available

Unavailable

Responding to OAM Discovery

Available

Transmitting Information

OAMPDUs

Available Available

123