Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Software Configuration Guide, Release 12.2(33)MRB
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Chapter 4 Configuring the Cisco MWR 2941 Router Using the CLI
Configuration Sequence
– All CFM frames at a lower level are stopped and dropped, independent of whether they
originate from the wire or relay function.
– All CFM frames at a higher level are forwarded, independent of whether they arrive from the
wire or relay function.
If the port on which a MIP is configured is blocked by Spanning-Tree Protocol, the MIP cannot receive
CFM messages or relay them toward the relay function side. The MIP can, however, receive and respond
to CFM messages from the wire.
A MIP has only one level associated with it and the command-line interface (CLI) does not allow you
to configure a MIP for a domain that does not exist.
Figure 4-4 illustrates MEPs and MIPs at the operator, service provider, and customer levels.
Figure 4-4 CFM MEPs and MIPs on Customer and Service Provider Equipment, Operator Devices
CFM Messages
CFM uses standard Ethernet frames. CFM frames are distinguishable by EtherType and for multicast
messages by MAC address. CFM frames are sourced, terminated, processed, and relayed by bridges.
Routers can support only limited CFM functions.
Bridges that cannot interpret CFM messages forward them as normal data frames. All CFM messages
are confined to a maintenance domain and to an S-VLAN (PE-VLAN or Provider-VLAN). Three types
of messages are supported:
• Continuity Check
• Loopback
• Traceroute
Equipment
Outward
facing
Inward
facing
Operator
level
Operator
level
Provider
level
Customer
level
MEP
MIP
Operator A Bridges Operator B Bridges Equipment
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