H3C S5120-EI Series Operation Manual page 231

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
Item
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
OAM connections can be initiated only by OAM entities operating in active OAM mode, while those
operating in passive mode wait and respond to the connection requests sent by their peers.
No OAM connection can be established between OAM entities operating in passive OAM mode.
After an Ethernet OAM connection is established, the Ethernet OAM entities on both sides exchange
Information OAMPDUs periodically to keep the Ethernet OAM connection valid. If an Ethernet OAM
entity receives no Information OAMPDU for five seconds, the Ethernet OAM connection is
disconnected.
Table 1-3 compares active Ethernet OAM mode with passive Ethernet
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