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
• Processes all CFM frames at its level coming from the direction of the relay function.
• Drops all CFM frames at a lower level coming from the direction of the relay function.
• Transparently forwards all CFM frames at its level (or a higher level), independent of whether they
come in from the relay function side or the wire side.
Note For the current Cisco IOS implementation, a MEP of level L (where L is less than 7) requires a
MIP of level M > L on the same port; hence, CFM frames at a level higher than the level of the
MEP are catalogued by this MIP.
• If the port on which the inward MEP is configured is blocked by Spanning-Tree Protocol, the MEP
can no longer transmit or receive CFM messages.
Outward Facing MEPs for Routed Ports and Switch Ports
Outward facing means that the MEP communicates through the wire. Outward facing MEPs can be
configured on routed ports and switch ports. A MIP configuration at a level higher than the level of the
outward facing MEP is not required.
Outward facing MEPs on routed ports use the port MAC address. Outward facing MEPs on port channels
use the Bridge-Brain MAC address of the first member link. When port channel members change, the
identities of outward facing MEPs do not have to change. Cisco IOS Release 12.2(33)MRA supports
outward facing MEPs on switch ports and Ethernet flow points (EFPs).
An outward facing MEP performs the following functions:
• Sends and receives CFM frames at its level via the wire connected to the port where the MEP is
configured.
• Drops all CFM frames at its level (or at a lower level) that come from the direction of the relay
function.
• Processes all CFM frames at its level coming from the direction of the wire.
• Drops all CFM frames at a lower level coming from the direction of the wire.
• Transparently forwards all CFM frames at levels higher than the level of the outward facing MEP,
independent of whether they come in from the relay function side or the wire side. This function is
not applicable to routed ports.
If the port on which the outward MEP is configured is blocked by Spanning-Tree Protocol, the MEP can
still transmit and receive CFM messages via the wire. Cisco IOS Release 12.2(33)MRA does not support
CFM messages passing through a blocked port.
Maintenance Intermediate Points
MIPs have the following characteristics:
• Act on a maintenance domain (level) and for all S-VLANs that are enabled or allowed on a port.
• Are internal to a domain, not at the boundary.
• Passive points respond only when triggered by CFM traceroute and loopback messages.
• Use Bridge-Brain MAC addresses.
• Handle CFM as follows:
– CFM frames received from MEPs and other MIPs are catalogued and forwarded, using both the
wire and the relay function.