How Ethernet Oam Works - 3Com 4500G Family Configuration Manual

Table 1-2 Functions of different types of OAMPDUs
OAMPDU type
Information
OAMPDU
Event
Notification
OAMPDU
Loopback
Control
OAMPDU

How Ethernet OAM Works

This section describes the working procedures of Ethernet OAM.
Ethernet OAM connection establishment
Ethernet OAM connection is the base of all the other Ethernet OAM functions. OAM connection
establishment is also known as the Discovery phase, where an Ethernet OAM entity discovers remote
OAM entities and establishes sessions with them.
In this phase, interconnected OAM entities notify the peer of their OAM configuration information and
the OAM capabilities of the local nodes by exchanging Information OAMPDUs and determine whether
Ethernet OAM connections can be established. An Ethernet OAM connection can be established only
when the settings concerning Loopback, link detecting, and link event of the both sides match. After an
Ethernet OAM connection is established, Ethernet OAM takes effect on it.
As for Ethernet OAM connection establishment, a device can operate in active Ethernet OAM mode or
passive Ethernet OAM mode.
OAM mode.
Table 1-3 Active Ethernet OAM mode and passive Ethernet OAM mode
Initiating OAM Discovery
Responding to OAM Discovery
Transmitting Information OAMPDUs
Transmitting Event Notification
OAMPDUs
Transmitting Information OAMPDUs
with the Data/Pad field being empty
Transmitting Loopback Control
OAMPDUs
Responding to Loopback Control
OAMPDUs
Used for transmitting state information of an Ethernet OAM entity (including the
information about the local device and remote devices, and customized
information) to the remote Ethernet OAM entity and maintaining OAM
connections
Used by link monitoring to notify the remote OAM entity when it detects problems
on the link in between.
Used for remote loopback control. By inserting the information used to
enable/disable loopback to a loopback control OAMPDU, you can enable/disable
loopback on a remote OAM entity.
Table 1-3 compares active Ethernet OAM mode with passive Ethernet
Item
Function
Active Ethernet OAM mode
Available
Available
Available
Available
Available
Available
Available (if both sides
operate in active OAM mode)
1-3
Passive Ethernet
OAM mode
Unavailable
Available
Available
Available
Available
Unavailable
Available