Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
OL-26895-01
Chapter 15 Configuring Ethernet OAM, CFM, and E-LMI
Understanding CFM ITU-T Y.1731 Fault Management
Ethernet Remote Defect Indication
When Ethernet OAM continuity check (ETH-CC) transmission is enabled, the Ethernet Remote Defect
Indication (ETH-RDI) function uses a bit in the CFM CC message to communicate defect conditions to
the MEP peers. For ETH-RDI functionality, you must configure the MEP MEG level, the ETH-CC
transmission period, and the ETH-CC frame priority. ETH-RDI does not require any MIP configuration.
When a MEP receives frames with ETH-RDI information, it determines that its peer MEP has
encountered a defect condition and sets the RDI files in the CCM frames for the duration of the defect
condition. When the defect condition clears, the MEP clears the RDI field.
When a MEP receives a CCM frame, it examines it to ensure that its MEG level is the same and if the
RDI field is set, it detects an RDI condition. For point-to-point Ethernet connections, a MEP can clear
the RDI condition when it receives the first frame from its peer MEP with the RDI field cleared.
However, for multipoint Ethernet connectivity, the MEP cannot determine the associated subset of peer
MEPs with which the sending MEP has seen the defect condition. It can clear the RDI condition after it
receives CCM frames with the RDI field cleared from its entire list of peer MEPs.
Ethernet Locked Signal
Note Ethernet locked signal is not supported in Release 15.0(1)MR.
The Ethernet Locked Signal (ETH-LCK) function communicates the administrative locking of a server
MEP and interruption of data traffic being forwarded to the MEP expecting the traffic. A MEP that
receives frames with ETH-LCK information can differentiate between a defect condition and an
administrative locking. ETH-LCK relies on loopback information (local and remote). The default timer
for ETH-LCK is 60 seconds and the default level is the MIP level.
When a MEP is administratively locked, it sends LCK frames in a direction opposite to its peer MEPs,
based on the LCK transmission period, which is the same as the AIS transmission period. The first LCK
frame is sent immediately following the administrative or diagnostic action.
A MEP receiving a LCK frame verifies that the maintenance level matches its configured maintenance
level, and detects a LCK condition. When no LCK frames are received for an interval of 3.5 times the
LCK transmission period, the MEP clears the LCK condition.
Multicast Ethernet Loopback
The multicast Ethernet loopback (ETH-LB) function verifies bidirectional connectivity of a MEP with
its peer MEPs and is an on-demand OAM function. When the feature is invoked on a MEP by entering
the ping privileged EXEC command, the MEP sends a multicast frame with ETH-LB request
information to peer MEPs in the same MEG. The MEP expects to receive a unicast frame with ETH-LB
reply information from its peer MEPs within a specified time period. A MEP receiving a multicast frame
with ETH-LB request information validates the frame and transmits a frame with reply information.
To configure multicast ETH-LB, you configure the MEG level of the MEP and the priority of the
multicast frames with ETH-LB requests. Multicast frames with ETH-LB request information are always
marked as drop ineligible. No MIP configuration is required.
The MEP sends multicast LB message frames on an on-demand basis. After sending a multicast LBM
frame, the MEP expects to receive LB reply frames within 5 seconds.