User's Manual

14-4
Link Fault: The number of unidirectional operation or fault can not be less than the high threshold in local.
Unidirectional Operation means unidirectional link can not work normally on full-duplex link without
auto-negotiation. EFM OAM can detect the fault and inform the remote OAM peers through sending
Information OAMPDU.
Dying Gasp: There is no definition present. Although device does not generate Dying Gasp OAMPDU, it still
receives and processes such OAMPDU sent by its peer.
4. Remote loopback testing
Remote loopback testing is available only after an Ethernet OAM connection is established. With remote
loopback enabled, operating Ethernet OAM entity in active mode issues remote loopback requests and the
peer responds to them. If the peer operates in loopback mode, it returns all packets except Ethernet
OAMPDUs to the senders along the original paths. Performing remote loopback testing periodically helps to
detect network faults in time. Furthermore, performing remote loopback testing by network segments helps to
locate network faults. Note: The communication will not be processed normally in remote loopback mode.
Typical EFM OAM application topology is in the following, it is used for point-to-point link and emulational
IEEE 802.3 point-to-point link. Device enables EFM OAM through point-to-point connection to monitor the link
fault in the First Mile with Ethernet access. For user, the connection between user to telecommunication is
“the First Mile”, for service provider, it is “the Last Mile”.
Figure 14-2 Typical
OAM application topology
14.2 EFM OAM Configuration
EFM OAM configuration task list
1. Enable EFM OAM function of port
2. Configure link monitor
3. Configure remote failure
4. Enable EFM OAM loopback of port
Note: it needs to enable OAM first when configuring OAM parameters.
Customer
Service Provider
Customer
CE
PE
802.1ah OAMPDU
802.3ah
Ethernet in
the First Mile