Falcon M-Class | User Guide
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4.21 Link OAM
The 802.3ah OAM standard provides the operation, administration and maintenance tools and
mechanisms for monitoring link operation, fault detection and remote loopback control.
The 802.3ah is a complete standard for Ethernet in the first mile, which contains a link level (as
opposed to service level) OAM mechanism. The protocol automatically discovers 802.3ah
neighbors on a link. It can monitor and detect link degradation or failure in both bi-directional links
and unidirectional links. Once a degradation or failure is detected, it provides diagnostic tools, e.g.
it can set a link to “loopback” mode in order to check and isolate specific link problems.
The IEEE link layer OAM operates at the Ethernet layer and therefore (unlike SNMP or Ping)does not require
an IP address.
The MIB variable retrieval operation allows collection of performance statistics.
The 802.3ah standard is a link oriented (port to port) protocol, i.e. it operates on a port level and
communicates with the neighbor device directly connected to its port.
M-Class series can communicate with any neighbour device supporting this protocol.
The major capabilities of 802.3ah are:
1. Discovery: detects the endpoints of a link and its OAM capabilities
2. Remote Fault Detection: allows one endpoint to convey severe events and failure
conditions to its OAM link partner (Link fault, Dying Gasp, specific critical events)
3. Link Performance Monitoring: detection and notifications of different link faults
Event notification is delivered to the link partner when one of these events is detected on
the link:
Frame Error events
Frame Period Error events
Symbol Period Error events
Event Seconds Summary
4. Remote Loopback: can be used to put the remote port in loopback mode, useful for data-
path test
5. MIB variable retrieval: collecting performance statistics
A MIB (Management Information Base) is a collection of variables which are deployed for
measuring the link capability to support the defined SLA.
6. Verification of link port status
7. Simultaneous operation on multiple ports
A typical link OAM scenario is shown below:
Figure 4-162: Sample Network with OAM functionality
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