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Configure a MEP to Generate and Respond to CFM Protocol Messages

A maintenance association end point (MEP) refers to the boundary of a domain. A MEP generates and responds to connectivity fault management (CFM) protocol messages. You can configure multiple up MEPs for a single combination of maintenance association ID and maintenance domain ID for interfaces belonging to a particular VPLS service or a bridge domain. You can configure multiple down MEPs for a single instance of maintenance domain identifier and maintenance association name to monitor services provided by Virtual Private LAN service (VPLS), bridge domain, circuit cross-connect (CCC), or IPv4 domains.

For layer 2 VPNs routing instances (local switching) and EVPN routing instances, you can also configure multiple up MEPs for a single combination of maintenance association ID and maintenance domain ID on logical interfaces. The logical interface can be configured on different devices or on the same device. To support multiple up MEPs on two IFLs, enhanced IP network services must be configured for the chassis.

You can enable automatic discovery of a MEP. With automatic discovery a MEP is enabled to accept continuity check messages (CCMs) from all remote MEPs of the same maintenance association. If automatic discovery is not enabled, the remote MEPs must be configured. If the remote MEP is not configured, the CCMs from the remote MEP are treated as errors.

Continuity measurement is provided by an existing continuity check protocol. The continuity for every remote MEP is measured as the percentage of time that remote MEP was operationally up over the total administratively enabled time. Here, the operational uptime is the total time during which the CCM adjacency is active for a particular remote MEP and the administrative enabled time is the total time during which the local MEP is active. You can also restart the continuity measurement by clearing the currently measured operational uptime and the administrative enabled time.

Configure a Maintenance Association End Point (MEP)

To configure a maintenance association end point:

  1. Specify an ID for the MEP at the [edit protocols oam ethernet connectivity-fault-management maintenance-domain domain-name maintenance-association ma-name]. You can specify any value from 1 through 8191.
  2. Enable maintenance end point automatic discovery so the MEP can accept continuity check messages (CCMs) from all remote MEPs of the same maintenance association.
  3. Specify the direction in which the CCM packets are transmitted for the MEP. You can specify up or down. If you specify the direction as up, CCMs are transmitted out of every logical interface that is part of the same bridging or VPLS instance except for the interface configured on the MEP. If you specify the direction as down, CCMs are transmitted only out of the interface configured on the MEP.
    Note:

    Ports in the Spanning Tree Protocol (STP) blocking state do not block CFM packets destined to a down MEP. Ports in an STP blocking state without the continuity check protocol configured do block CFM packets.

    Note:

    Starting with Junos OS Release 12.3, for all interfaces configured on Modular Port Concentrators (MPCs) on MX Series 5G Universal Routing Platforms, you no longer need to configure the no-control-word statement for all Layer 2 VPNs and Layer 2 circuits over which you are running CFM MEPs. For all other interfaces on MX Series routers and on all other routers and switches, you must continue to configure the no-control-word statement at the [edit routing-instances routing-instance-name protocols l2vpn] or [edit protocols l2circuit neighbor neighbor-id interface interface-name] hierarchy level when you configure CFM MEPs. Otherwise, the CFM packets are not transmitted, and the show oam ethernet connectivity-fault-management mep-database command does not display any remote MEPs.

  4. Specify the interface to which the MEP is attached. It can be a physical interface, logical interface, or trunk interface. On MX Series routers, the MEP can be attached to a specific VLAN of a trunk interface.
  5. Specify the IEEE 802.1 priority bits that are used by continuity check and link trace messages. You can specify a value from through 7 as the priority.
  6. Specify the lowest priority defect that generates a fault alarm whenever CFM detects a defect. Possible values include: all -defects, err-xcon, mac-rem-err-xcon, no-defect, rem-err-xcon, and xcon.
  7. Specify the ID of the remote MEP at the [edit protocols oam ethernet connectivity-fault-management maintenance-domain domain-name maintenance-association ma-name mep mep-id]. You can specify any value from 1 through 8191.

See Also

Configure a Remote Maintenance Association End Point (MEP)

To configure a remote maintenance association end point:

  1. Configure the remote MEP by specifying the MEP ID at the [edit protocols oam ethernet connectivity-fault-management maintenance-domain domain-name maintenance-association ma-name mep mep-id]. You can specify any value from 1 through 8191.
  2. Specify the name of the action profile to be used for the remote MEP by including the action-profile profile-name statement at the [edit protocols oam ethernet connectivity-fault-management maintenance-domain domain-name maintenance-association ma-name mep mep-id remote-mep remote-mep-id]. The profile must be defined at the [edit protocols oam ethernet connectivity-fault-management] hierarchy level.
  3. Configure the remote MEP to detect initial loss of connectivity. By default, the MEP does not generate loss-of-continuity (LOC) defect messages. When you configure the detect-loc statement, a loss-of-continuity (LOC) defect is detected if no continuity check message is received from the remote MEP within a period equal to 3.5 times the continuity check interval configured for the maintenance association. If a LOC defect is detected, a syslog error message is generated.
    Note:

    When you configure connectivity-fault management (CFM) along with detect-loc, any action-profile configured to bring down the interface is executed if continuity check message is not received . However, the action-profile is not executed if you have not configured detect-loc and continuity check message is not received.

See Also

Related Documentation

Release History Table
Release
Description
12.3
Starting with Junos OS Release 12.3, for all interfaces configured on Modular Port Concentrators (MPCs) on MX Series 5G Universal Routing Platforms, you no longer need to configure the no-control-word statement for all Layer 2 VPNs and Layer 2 circuits over which you are running CFM MEPs.