Configuring an SLM

Synthetic loss measurement (SLM) is part of the ITU-T Y.1731 standard. It can be used to periodically measure Frame Loss and Forward Loss Ratio (FLR) between a pair of point to point MEPs. Measurements are made between two MEPs that belong to the same domain and MA.

Configuring SLM over VPLS

This section describes the procedure for configuring SLM over VPLS.

Note

The EVC name is mandatory in the VPLS configuration methods.

SUMMARY STEPS

    1.    Configure CFM on PE Device

    2.    Configure CFM over VPLS using l2 vfi vfi-name manual evc command or l2vpn vfi context vfi-name command.

    3.    Configure a Sender MEP (optional task).


DETAILED STEPS
     Command or ActionPurpose
    Step 1 Configure CFM on PE Device  

    For configuration details, see Configuring Ethernet Connectivity Fault Management in a Service Provider Network. In case of H-VPLS configuration, see CFM Configuration over EFP Interface with Cross Connect Feature.

     
    Step 2Configure CFM over VPLS using l2 vfi vfi-name manual evc command or l2vpn vfi context vfi-name command.  

    The evc should be the EVC name used in the CFM on PE device configuration. For configuration details, see Configuring the VFI in the PE.

    Note   

    The EVC name is mandatory in both the above mentioned VPLS configuration methods.

     
    Step 3Configure a Sender MEP (optional task).  

    For configuration details, see Configuring a Sender MEP for a Single-Ended Ethernet Frame Loss Ratio Operation.

     

    Restrictions for SLM support over VPLS

    • Only Up MEP (Maintenance End Point) on EVC (ethernet virtual circuit) BD (bridge domain) with VPLS towards the core is supported. Down MEP on VFI is not supported.

    • To send unicast packets (LBR, LTM/R, Y1731 packets), port-emulation method is used. The access interface (the interface where Up MEP is configured) needs to be up to send unicast packets.

    • SLM is not supported with TEFP in access.

    • SLM scales with frame interval of 100ms.

    Configuring an SLM

    To configure an SLM, execute the following commands:

    SUMMARY STEPS

      1.    enable

      2.    configure terminal operation number

      3.    ip sla operation number

      4.    ethernet y1731 loss SLM domain domain-name {evc evc-id | vlan vlan-id}{mpid target-mp-id | mac-address-target -address}cos cos{source{mpid source-mp-id | mac-address source-address}}

      5.    aggregate interval seconds

      6.    availability algorithm{ sliding-window | static-window 1} symmetric

      7.    frame consecutive value

      8.    frame interval milliseconds

      9.    framesize bytes

      10.    history interval intervals-stored

      11.    owner owner-id

      12.    exit

      13.    exit

      14.    ip sla reaction-configuration operation-number [react {unavailableDS |unavailableSD | loss-ratioDS | loss-ratioSD} ] [threshold-type {average [number -of-measurements] | consecutive [occurences] | immediate} ] [threshold-value upper -threshold lower-threshold]

      15.    ip sla logging traps

      16.    exit


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example: 
      Router > enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 configure terminal operation number


      Example: 
      Device# configure terminal
       

      —Identifies the IP SLAs' operation you want to configure.

      Enters global configuration mode.

       
      Step 3 ip sla operation number


      Example: 
      Router(config)# ip sla 11
       

      Configures an IP SLA operation and enters IP SLA configuration mode.

      • operation-number—Identifies the IP SLAs' operation you want to configure.

       
      Step 4 ethernet y1731 loss SLM domain domain-name {evc evc-id | vlan vlan-id}{mpid target-mp-id | mac-address-target -address}cos cos{source{mpid source-mp-id | mac-address source-address}}


      Example: 
      Router(config-ip-sla)# ethernet y1731 loss SLM domain xxx evc yyy mpid 101 cos 4 source mpid 100
       

      Configures a single-ended synthetic loss measurement and enters IP SLA Y.1731 loss configuration mode.

      • SLM—Specifies that the frames sent are Synthetic Loss Measurement (SLM) frames.

      • domain domain-name—Specifies the name of the Ethernet Connectivity Fault Management (CFM) maintenance domain.

      • vlan vlan-id—Specifies the VLAN identification number. The range is from 1 to 4096.

      • mpid target-mp-id—Specifies the maintenance endpoint identification numbers of the MEP at the destination. The range is from 1 to 8191.

      • mac-addresstarget-address—Specifies the MAC address of the MEP at the destination.

      • coscos—Specifies, for this MEP, the class of service (CoS) that will be sent in the Ethernet message. The range is from 0 to 7.

      • source—Specifies the source MP ID or MAC address.

      • mpid source-mp-id—Specifies the maintenance endpoint identification numbers of the MEP being configured. The range is from 1 to 8191.

      • mac-address source-address—Specifies the MAC address of the MEP being configured.

       
      Step 5 aggregate interval seconds


      Example: 
      Router(config-sla-y1731-loss)# aggregate interval 900
       

      (Optional) Configures the length of time during which the performance measurements are conducted and the results stored.

      • seconds—Specifies the length of time in seconds. The range is from 1 to 65535. The default is 900.

       
      Step 6 availability algorithm{ sliding-window | static-window 1} symmetric


      Example: 
      Router(config-sla-y1731-loss)# availability algorithm static-window
       

      ( Optional) Specifies availability algorithm used.

      • sliding-window—Specifies a sliding-window control algorithm.

      • static-window—Specifies static-window control algorithm.

       
      Step 7 frame consecutive value


      Example: 
      Router(config-sla-y1731-loss)# frame consecutive 10.
              		(Optional) Specifies number of consecutive measurements to be used to determine availability or unavailability status.

      • value—Specifies the number of consecutive measurements. The range is from 1 to 10. The default is 10.

       
      Step 8 frame interval milliseconds


      Example: 
      Router(config-sla-y1731-loss)# frame interval 100
              		(Optional) Sets the gap between successive frames.

      • milliseconds—Specifies the length of time in milliseconds (ms) between successive synthetic frames. The range is from 100 to 10000. The default is 1000

       
      Step 9 framesize bytes


      Example: 
      Router(config-sla-y1731-loss)# frame size 32
       

      (Optional) Configures padding size for frames.

      • bytes—Specifies the padding size, in four-octet increments, for the synthetic frames. The range is from 64 to 384. The default is 64.

       
      Step 10history interval intervals-stored


      Example: 

      Router(config-sla-y1731-loss)# history interval 2
       

      (Optional) Sets the number of statistics distributions kept during the lifetime of an IP SLAs Ethernet operation.

      • intervals-stored—Specifies the number of statistics distributions. The range is from 1 to 10. The default is 2.

       
      Step 11owner owner-id


      Example: 
      Router(config-sla-y1731-loss)# owner admin
       

      (Optional) Configures the owner of an IP SLAs operation.

      • owner-id—Specified the name of the SNMP owner. The value is from 0 to 255 ASCII characters.

       
      Step 12exit


      Example: 
      Router(config-sla-y1731-loss)# exit
       

      Exits IP SLA Y.1731 loss configuration mode and enters IP SLA configuration mode.

       
      Step 13exit


      Example: 
      Router(config-ip-sla)# exit
       

      (Optional) Configures proactive threshold monitoring for frame loss measurements.

       
      Step 14ip sla reaction-configuration operation-number [react {unavailableDS |unavailableSD | loss-ratioDS | loss-ratioSD} ] [threshold-type {average [number -of-measurements] | consecutive [occurences] | immediate} ] [threshold-value upper -threshold lower-threshold]


      Example: 
      Router(config)# ip sla reaction-configuration 11 react unavailableDS
       
      (Optional) Configures proactive threshold monitoring for frame loss measurements.

      • operation-number—Identifies the IP SLAs operation for which reactions are to be configured.

      • react—(Optional) Specifies the element to be monitored for threshold violations.

      • unavailableDS—Specifies that a reaction should occur if the percentage of destination-to-source Frame Loss Ratio (FLR) violates the upper threshold or lower threshold.

      • unavailableSD—Specifies that a reaction should occur if the percentage of source-to-destination FLR violates the upper threshold or lower threshold.

      • loss-ratioDS—Specifies that a reaction should occur if the one-way destination-to-source loss-ratio violates the upper threshold or lower threshold.

      • loss-ratioSD—Specifies that a reaction should occur if the one way source-to-destination loss-ratio violates the upper threshold or lower threshold.

      • threshold-type average[ number-of-measurements]—(Optional) When the average of a specified number of measurements for the monitored element exceeds the upper threshold or when the average of a specified number of measurements for the monitored element drops below the lower threshold, perform the action defined by the action-type keyword. The default number of 5 averaged measurements can be changed using the number-of-measurements argument. The range is from 1 to 16.

      • threshold-type consecutive[occurrences] —(Optional) When a threshold violation for the monitored element is met consecutively for a specified number of times, perform the action defined by the action-type keyword. The default number of 5 consecutive occurrences can be changed using the occurrences argument. The range is from 1 to 16.

      • threshold-type immediate—(Optional) When a threshold violation for the monitored element is met, immediately perform the action defined by the action-type keyword.

      • threshold-valueupper-threshold lower-threshold—(Optional) Specifies the upper-threshold and lower-threshold values of the applicable monitored elements.

       
      Step 15ip sla logging traps


      Example: 
      Router(config)# ip sla logging traps
       

      (Optional) Enables IP SLAs syslog messages from CISCO-RTTMON-MIB.

       
      Step 16exit


      Example: 
      Router(config)# exit
       

      Exits global configuration mode and enters privileged EXEC mode.

       
      What to Do Next

      Once the SLM is configured, you have to schedule an IP SLA operation.

      Scheduling an IP SLA Operation

      To schedule an IP SLA operation, execute the following commands:

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    ip sla schedule operation-number start-time now ip sla schedule operation-number

        4.    exit


      DETAILED STEPS
         Command or ActionPurpose
        Step 1enable


        Example: 
        Router> enable
         

        Enables the privileged EXEC mode.

        Enter your password if prompted.

         
        Step 2configure terminal


        Example: 
        Router# configure terminal
         

        Enters the global configuration mode.

         
        Step 3ip sla schedule operation-number start-time now ip sla schedule operation-number


        Example: 
        Router(config)# ip sla schedule 10 start-time now


        Example: 
        Router(config)# ip sla group schedule 1 3,4,6-9
         

        Configures the scheduling parameters for an individual IP SLA operation or Specifies an IP SLA operation group number and the range of operation numbers to be scheduled for a multi-operation scheduler.

         
        Step 4exit


        Example: 
        Router(config)# exit
         

        Exits the global configuration mode and enters the privileged EXEC mode.

         

        Configuration Example for SLM over VPLS

        This section lists the CLIs and their corresponding outputs of SLM configuration over VPLS that are generated.

        • sh run | i evc 
          ethernet evcEVC_100
        • sh run | sec cfm 
          ethernet cfm global
ethernet cfm domain CFM-VPLS level 5
service ser1 evc EVC_100 vlan 100
continuity-check
continuity-check interval 1s
        • sh run | sec 12 vfi 
          l2 vfi VPLS-CFM manual EVC_100
vpn id 100
bridge-domain 100
neighbor 2.2.2.2 encapsulation mpls
        • sh run int g0/4/4 
          interface GigabitEthernet0/4/4
service instance 100 ethernet EVC_100
encapsulation dot1q 100

cfm mep domain CFM-VPLS mpid 1001
bridge-domain 100
        • sh run | sec ip sla 
          ip sla 200
ethernet y1731 loss SLM domain CFM-VPLS evc EVC_100 mpid 1002 cos 7 source mpid 1001
ip sla schedule 200 start-time now