Specifications

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System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 17 Configuring Ethernet OAM, CFM, and E-LMI
Information About Ethernet CFM
leak error could occur if other maintenance associations associated with the same VLAN exist at a higher
level without any MEPs configured. You can display the configuration error list, which is informational
only, by entering the show ethernet cfm errors configuration privileged EXEC command.
CFM Version Interoperability
When customers upgrade their network from the Cisco CFM draft 1 to IEEE standardized 802.1ag CFM,
they might not upgrade all equipment at the same time, which could result in a mix of Cisco CFM draft 1
and IEEE standardized CFM devices in the network. CFM areas are regions in a network running Cisco
CFM draft 1 software. Internal area bridges are all Cisco devices running CFM draft 1, and external area
bridges are devices (Cisco or third-party devices) running IEEE standardized 802.1ag CFM.
Devices at the edge of these areas perform message translation. Translation is not needed for
maintenance domains that do not span different areas (that is, where CFM messages end on a port on the
device) since the port can respond in the same message format as was received. However, for
maintenance domains that span across two areas, the device must translate the CFM message
appropriately before sending it on to the other area.
When designing a network with CFM areas, follow these guidelines:
• Whenever possible, group devices with the same CFM version together.
• Minimize the number of boundaries between CFM clusters, minimizing the number of devices that
must perform translation.
• Never mix CFM versions on a single segment.
When the network does use both versions of CFM, you can enable translation on the CFM 802.1ag port
that is connected to the draft 1 device by entering the ethernet cfm version cisco interface configuration
command.
Note If you are running CFM draft 1 and upgrade to a software version that supports CFM 802.1ag, the switch
automatically transfers the draft 1 configuration to the standard.
IP SLAs Support for CFM
The switch supports CFM with IP Service Level Agreements (SLAs), which provides the ability to
gather Ethernet layer network performance metrics. Available statistical measurements for the IP SLAs
CFM operation include round-trip time, jitter (interpacket delay variance), and packet loss. You can
schedule multiple IP SLAs operations and use Simple Network Management Protocol (SNMP) trap
notifications and syslog messages for proactive threshold violation monitoring.
For more information about IP SLAs, see Chapter 16, “Configuring Cisco IOS IP SLAs Operations.”
IP SLAs integration with CFM gathers Ethernet layer statistical measurements by sending and receiving
Ethernet data frames between CFM MEPs. Performance is measured between the source MEP and the
destination MEP. Unlike other IP SLAs operations that provide performance metrics for only the IP
layer, IP SLAs with CFM provides performance metrics for Layer 2.
You can manually configure individual Ethernet ping or jitter operations. You can also configure an IP
SLAs automatic Ethernet operation that queries the CFM database for all MEPs in a given maintenance
domain and VLAN. The operation then automatically creates individual Ethernet ping or jitter
operations based on the discovered MEPs.