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Configuring Ethernet Synthetic Loss Measurements

 

Use this topic to understand the guidelines for configuring synthetic loss measurement and how to start a synthetic loss measurement session. There are two types of synthetic loss measurement sessions: proactive and On-Demand. This topic describes both. Also, the topic shows you how to view and clear the synthetic loss measurement statistics and how to troubleshoot failures with SLM.

Guidelines for Configuring ETH-SLM

Keep the following points in mind when you configure the ETH-SLM functionality:

  • The monitoring application for Ethernet OAM is initiated in the master Routing Engine. When a stateful switchover process occurs, the monitoring application is disabled. For on-demand ETH-SLM, graceful Routing Engine switchover (GRES) support is not applicable. For proactive ETH-SLM, the service-level agreement (SLA) iterators are restored during a stateful switchover process. If the adjacencies do not time out, the ETH-SLM statistics are preserved and proactive ETH-SLM supports GRES.

  • ETH-SLM is initiated only when the MEP session is up. Unified in-service software upgrade (ISSU) support for ETH-SLM depends on the unified ISSU support for CFM. For CFM, unified ISSU is supported using the loss threshold TLV to avoid CFM connectivity loss during the upgrade. The receiving or the destination MEP increases the threshold time during the termination of sessions. If you start a unified ISSU operation when on-demand ETH-SLM is in progress, the SLM request and reply messages are lost at the local Packet Forwarding Engine.

    When an on-demand ETH-SLM is requested, if the local source MEP undergoes a unified ISSU, a message is displayed stating that the MEP is undergoing a unified ISSU. If the remote MEP is undergoing a unified ISSU (detected through the loss threshold TLV), a message is displayed stating that the remote MEP is undergoing a unified ISSU. Also, if it is not possible to identify whether unified ISSU is in progress on a remote MEP, the SLM packets are lost at the system where unified ISSU is in progress and the loss calculation results do not provide a valid cause for the loss. Unified ISSU is not supported for both on-demand and proactive ETH-SLM.

  • The maximum number of SLA iterator profiles that can be configured in the system is 255.

  • ETH-SLM is not supported for virtual private LAN service (VPLS) (point-to-multipoint measurements are not supported). The ETH-SLM frames are not generated with multicast class 1 destination address. Similarly, ETH-SLM does not respond to ETH-SLM requests with multicast DA. ETH-SLM for VPLS for point-to-point Ethernet connection is supported using directed unicast destination MAC addresses, although point-to-multipoint topologies are not supported.

  • A unicast destination address may be used in provisioned environments for point-to-point connections. However, it requires that the unicast destination address of the downstream MEP must have been configured on the MEP transmitting an alarm indication signal (AIS).

  • ETH-SLM is not supported on downstream MEPs on label-switched interfaces (LSIs).

  • ETH-SLM is supported on aggregated Ethernet (ae) interfaces

  • The number of ETH-SLM sessions for proactive ETH-SLM that can be supported is limited to the total number of iterators that can be supported in the system. This limitation includes the iterator support for other measurement types such as loss, statistical frame loss, and two-way delay. A new iterator type, SLM, is added to support ETH-SLM. The total number of SLA iterators that you can configure in the system is equal to the total number of iterations supported in the system.

  • For on-demand SLM, the minimum period between two SLM requests is 100 milliseconds.

  • For proactive SLM, the minimum period between two SLM requests is 10 milliseconds for distributed mode and 100 milliseconds for non-distributed mode.

  • ETH-SLM frames are always marked as drop-ineligible in compliance with the ITU-T Y.1731 standard.

Starting a Proactive ETH-SLM Session

To start a proactive Ethernet synthetic loss measurement (ETH-SLM) session, you must configure the Ethernet interfaces on maintenance association end points (MEPs) on which packets transmitted with synthetic frame loss need to be analyzed. You must then create an iterator profile to transmit service-level agreement (SLA) measurement packets for ETH-SLM and associate the local and remote MEPs with the profile.

Configuring MEP Interfaces

Before you can start an Ethernet synthetic frame loss measurement session across an Ethernet service, you must configure two ACX Series routers to support ETH-SLM.

To configure an Ethernet interface on an ACX Series router to support ETH-SLM:

  1. On each router, configure two physical or logical Ethernet interfaces connected by a VLAN. The following configuration is typical for single-tagged logical interfaces:

    Both interfaces will use the same VLAN ID.
  2. On each router, attach peer MEPs to the two interfaces. The following configuration is typical:

Configuring an Iterator Profile for ETH-SLM

You can create an iterator profile with its parameters to periodically transmit SLA measurement packets in the form of ITU-Y.1731-compliant frames for synthetic loss measurement.

Note

ACX5048 and ACX5096 routers supports iterator cycle time of only 1 second and above.

To create an iterator profile:

  1. In configuration mode, go to the following hierarchy level:
  2. Configure the SLA measurement monitoring iterator:
  3. Configure an iterator profile—for example, i1:
  4. (Optional) Configure the cycle time, which is the amount of time (in milliseconds) between back-to-back transmission of SLA frames for one connection, with a value from 10 through 3,600,000. The default value is 1000 ms.
  5. (Optional) Configure the iteration period, which indicates the maximum number of cycles per iteration (the number of connections registered to an iterator cannot exceed this value), with a value from 1 through 2000. The default value is 2000.
  6. Configure the measurement type as synthetic loss measurement.
  7. Configure the disable statement to stop the iterator (that is, disable the iterator profile).
  8. Verify the configuration.

Associating the Iterator Profile with MEPs for ETH-SLM

You can associate a remote maintenance association end point (MEP) with more than one iterator profile.

To configure a remote MEP with an iterator profile:

  1. In configuration mode, go to the following hierarchy level:
  2. Configure the remote MEP ID with a value from 1 through 8191.
  3. Set the iterator profile.
  4. (Optional) Set the size of the data TLV portion of the Y.1731 data frame with a value from 1 through 1400 bytes. The default value is 1.
  5. (Optional) Set the iteration count, which indicates the number of iterations for which this connection should partake in the iterator for acquiring SLA measurements, with a value from 1 through 65,535. The default value is 0 (that is, infinite iterations).
  6. (Optional) Set the priority, which is the vlan-pcp value that is sent in the Y.1731 data frames, with a value from 0 through 7. The default value is 0.
  7. Verify the configuration.

Starting an On-Demand ETH-SLM Session

To start an on-demand Ethernet synthetic loss measurement (ETH-SLM) session, type the monitor ethernet synthetic-loss-measurement one-way command in operational mode, and specify the peer MEP by its MAC address or by its MEP identifier.

For example:

user@host> monitor ethernet synthetic-loss-measurement 00:05:85:73:39:4a maintenance-domain md6 maintenance-association ma6 count 10
Note

If you attempt to monitor delays to a nonexistent MAC address, you must press Ctrl + C to explicitly quit the monitor ethernet synthetic-loss-measurement command and return to the CLI command prompt.

Managing ETH-SLM Statistics and ETH-SLM Frame Counts

Displaying ETH-SLM Statistics Only

Purpose

Display on-demand ETH-SLM statistics.

By default, the show oam ethernet connectivity-fault-management synthetic-loss-statistics command displays on-demand ETH-SLM statistics for MEPs in the specified CFM maintenance association within the specified CFM maintenance domain.

Action

  • To display the on-demand ETH-SLM statistics collected for MEPs belonging to maintenance association ma1 within maintenance domain md1:

    user@host> show oam ethernet connectivity-fault-management synthetic-loss-statistics maintenance-domain md1 maintenance-association ma1
  • To display the on-demand ETH-SLM statistics collected for ETH-SLM sessions for the local MEP 201 belonging to maintenance association ma2 within maintenance domain md2:

    user@host> show oam ethernet connectivity-fault-management synthetic-loss-statistics maintenance-domain md2 maintenance-association ma2 local-mep 201
  • To display the on-demand ETH-SLM statistics collected for ETH-SLM sessions from local MEPs belonging to maintenance association ma3 within maintenance domain md3 to the remote MEP 302:

    user@host> show oam ethernet connectivity-fault-management synthetic-loss-statistics maintenance-domain md3 maintenance-association ma3 remote-mep 302

Meaning

The output displays on-demand ETH-SLM statistics for MEPs in the specified maintenance association within the specified maintenance domain. For details about the output of this command and the descriptions of the output fields, see show oam ethernet connectivity-fault-management synthetic-loss-statistics.

See also

  • show oam ethernet connectivity-fault-management synthetic-loss-statistics

Displaying ETH-SLM Statistics and Frame Counts

Purpose

Display on-demand ETH-SLM statistics and ETH-SLM frame counts.

By default, the show oam ethernet connectivity-fault-management mep-statistics command displays on-demand ETH-SLM statistics and frame counts for MEPs in the specified CFM maintenance association within the specified CFM maintenance domain.

Action

  • To display the on-demand ETH-SLM statistics and ETH-SLM frame counts for MEPs in maintenance association ma1 within maintenance domain md1:

    user@host> show oam ethernet connectivity-fault-management mep-statistics maintenance-domain md1 maintenance-association ma1
  • To display the on-demand ETH-SLM statistics and ETH-SLM frame counts for the local MEP 201 in maintenance association ma2 within maintenance domain md2:

    user@host> show oam ethernet connectivity-fault-management mep-statistics maintenance-domain md2 maintenance-association ma2 local-mep 201
  • To display the on-demand ETH-SLM statistics and ETH-SLM frame counts for the local MEP in maintenance association ma3 within maintenance domain md3 that participates in an ETH-SLM session with the remote MEP 302:

    user@host> show oam ethernet connectivity-fault-management mep-statistics maintenance-domain ma3 maintenance-association ma3 remote-mep 302

Meaning

The output displays on-demand ETH-SLM statistics and ETH-SLM frame counts for MEPs in the specified maintenance association within the specified maintenance domain. For details about the output of this command and the descriptions of the output fields, see show oam ethernet connectivity-fault-management mep-statistics.

See also

  • show oam ethernet connectivity-fault-management mep-statistics

Displaying ETH-SLM Frame Counts for MEPs by Enclosing CFM Entity

Purpose

Display on-demand ETH-SLM frame counts for CFM maintenance association end points (MEPs).

By default, the show oam ethernet connectivity-fault-management mep-database command displays CFM database information for MEPs in the specified CFM maintenance association within the specified CFM maintenance domain.

Note

At the router attached to the initiator MEP for a one-way session, or at the router attached to the receiver MEP for a two-way session, you can only display the ETH-SLM frame counts and not the MEP database details.

Action

  • To display CFM database information (including ETH-SLM frame counts) for all MEPs in MA ma1 within maintenance domain md1:

    user@host> show oam ethernet connectivity-fault-management mep-database maintenance-domain ma1 maintenance-association ma1
  • To display CFM database information (including ETH-SLM frame counts) only for the local MEP 201 in MA ma1 within maintenance domain md1:

    user@host> show oam ethernet connectivity-fault-management mep-database maintenance-domain md2 maintenance-association ma2 local-mep 201
  • To display CFM database information (including ETH-SLM frame counts) only for the remote MEP 302 in MA ma3 within maintenance domain md3:

    user@host> show oam ethernet connectivity-fault-management mep-database maintenance-domain ma3 maintenance-association ma3 remote-mep 302

Meaning

The output displays ETH-SLM frame counts for MEPs within a particular maintenance domain, or for a specific local or remote MEP. For details about the output of this command and the descriptions of the output fields, see show oam ethernet connectivity-fault-management mep-database.

See also

  • show oam ethernet connectivity-fault-management mep-database

Displaying ETH-SLM Frame Counts for MEPs by Interface or Domain Level

Purpose

Display on-demand ETH-SLM frame counts for CFM maintenance association end points (MEPs).

By default, the show oam ethernet connectivity-fault-management interfaces command displays CFM database information for MEPs attached to CFM-enabled Ethernet interfaces on the router or at a maintenance domain level. For Ethernet interfaces that support ETH-SLM, any frame counts are also displayed when you specify the detail or extensive command option.

Note

At the router attached to the initiator MEP, you can only display the ETH-SLM frame counts and not the MEP database details.

Action

  • To display CFM database information (including ETH-SLM frame counts) for all MEPs attached to CFM-enabled Ethernet interfaces on the router:

    user@host> show oam ethernet connectivity-fault-management interfaces detail
  • To display CFM database information (including ETH-SLM frame counts) only for the MEPs attached to CFM-enabled router interface ge-5/2/9.0:

    user@host> show oam ethernet connectivity-fault-management interfaces ge-5/2/9.0 detail
  • To display CFM database information (including ETH-SLM frame counts) only for MEPs enclosed within CFM maintenance domains at level 6:

    user@host> show oam ethernet connectivity-fault-management interfaces level 6 detail

Meaning

The output displays ETH-SLM frame counts for MEPs for the specified interface. For details about the output of this command and the descriptions of the output fields, see show oam ethernet connectivity-fault-management interfaces.

See also

  • show oam ethernet connectivity-fault-management interfaces

Clearing ETH-SLM Statistics and Frame Counts

Purpose

Clear the on-demand ETH-SLM statistics and ETH-SLM frame counts.

By default, statistics and frame counts are deleted for all MEPs attached to CFM-enabled interfaces on the router. However, you can filter the scope of the command by specifying an interface name.

Action

  • To clear the on-demand ETH-SLM statistics and ETH-SLM frame counts for all MEPs attached to CFM-enabled interfaces on the router:

    user@host> clear oam ethernet connectivity-fault-management synthetic-loss-measurement
  • To clear the on-demand ETH-SLM statistics and ETH-SLM frame counts only for MEPs attached to the logical interface ge-0/5.9.0:

    user@host> clear oam ethernet connectivity-fault-management synthetic-loss-measurement ge-0/5/9.0

Clearing Iterator Statistics

Purpose

Clear the existing iterator statistics and proactive ETH-SLM counters.

Multiple iterators can be associated with remote MEP. However, by default, only one result pertaining to one iterator profile can be cleared.

Action

  • To clear the iterator statistics for remote MEP 1 and iterator profile i1 with MEPs belonging to the maintenance association  ma1 within the maintenance domain default-1:

    user@host> clear oam ethernet connectivity-fault-management sla-iterator-statistics sla-iterator i1 maintenance-domain default-1 maintenance-association ma1 local-mep 1 remote-mep 1
  • To clear the iterator statistics for remote MEP 1 and iterator profile i2 with MEPs belonging to the maintenance association ma1 within the maintenance domain default-1:

    user@host> clear oam ethernet connectivity-fault-management sla-iterator-statistics sla-iterator i2 maintenance-domain default-1 maintenance-association ma1 local-mep 1 remote-mep 1

Troubleshooting Failures with ETH-SLM

Problem

Description: The Ethernet synthetic loss measurement (ETH-SLM) application is not working properly for calculation of frame loss using synthetic frames instead of data traffic

Solution

Perform the following steps to analyze and debug any problems with the ETH-SLM functionality.

  1. Ensure that ETH-SLM is configured (either proactive or on-demand) to initiate SLM frames. Verify the configuration settings.
  2. Examine any failures that might have occurred in the CFM session for which the ETH-SLM feature is enabled. The CFM session must be in the up state for the ETH-SLM functionality to work correctly. Use the show oam ethernet connectivity-fault-management mep-database maintenance-domain md-name maintenance-association ma-name local-mep mep-id remote-mep remote-mep-id command to verify whether the CFM session is in the up state.
  3. If the MEP sessions are active, use the appropriate show command to verify the ETH-SLM statistics and to analyze if ETH-SLM frames are transmitted or received.
  4. If the transmission of ETH-SLM frames does not happen correctly after you attempt all of the preceding troubleshooting steps, enable the tracing operations for Ethernet CFM by including the traceoptions statement at the [edit protocols oam ethernet connectivity-fault-management] hierarchy level.