G.8032 and CFM Support for Microwave Adaptive Bandwidth
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G.8032 and CFM Support for Microwave Adaptive Bandwidth

The G.8032 and CFM Support for Microwave Adaptive Bandwidth feature enables the G.8032 Ethernet Protection Ring (ERP) mechanism to be used as a trigger in response to bandwidth degradation occurrences (such as a signal degradation [SD] indicator) on microwave links. Ethernet Connectivity Fault Management (CFM) interacts with the microwave transceiver to continuously check the quality and the bandwidth of the microwave link. When microwave link degradation (based on the configured service level agreement [SLA] in use) is detected, CFM notifies the G.8032 ERP mechanism, which in turn ensures that the degraded microwave link is bypassed and no longer used. The degraded microwave link can still be used by one or more of the G.8032 ERP instances. Only the affected G.8032 ERP instances are switched to alternate link.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for G.8032 and CFM Microwave Adaptive Bandwidth Support

  • The microwave transceiver in the network topology must support adaptive bandwidth modulation, and the microwave transceiver must support the Ethernet Connectivity Fault Management (CFM) extension for microwave devices as defined by Cisco.
  • In a heterogeneous ring topology, all devices connected directly to the microwave transceiver must support signal degradation (SD) functions. Devices not connected directly to the microwave transceiver can be standard-compliant nodes or enhanced SD-capable nodes.
  • In a homogeneous ring topology, all links must be microwave links and all devices must support microwave SD-based ring protection.
  • A ring topology with multiple microwave links can experience a signal degradation condition on one or more of the microwave links. Only one signal degradation condition per ring instance is supported. This support is provided on a first-come, first-serve basis, per ring instance.

About G.8032 and CFM Support for Microwave Adaptive Bandwidth

Microwave Adaptive Bandwidth Feature Functionality

The G.8032 and CFM Support for Microwave Adaptive Bandwidth feature extends the functionality of the G.8032 Ethernet Protection Ring (ERP) mechanism and Ethernet Connectivity Fault Management (CFM).

This feature enables the G.8032 ERP mechanism to be used as a trigger in response to bandwidth degradation occurrences (such as a signal degradation [SD] indicator) on microwave links. Ethernet CFM interacts with the microwave transceiver to continuously check the quality and the bandwidth of the microwave link. When microwave link degradation (based on the configured service level agreement [SLA] in use) is detected, CFM notifies the G.8032 ERP mechanism, which in turn ensures that the degraded microwave link is bypassed and no longer used. Depending upon the severity of the signal degradation and the configured threshold, G.8032 protection switching occurs on a per-instance basis.

For more information about Ethernet CFM, see the “Configuring IEEE Standard-Compliant Ethernet CFM in a Service Provider Network” module or the “Configuring Ethernet Connectivity Fault Management in a Service Provider Network” module.

For more information about G.8032 ERP, see the “ITU-T G.8032 Ethernet Ring Protection Switching” module.

Fixed Versus Adaptive Bandwidth Modulation and the Microwave Adaptive Bandwidth Feature

Traditional microwave radios use fixed modulation schemes whereby any degradation in the wave propagation conditions (for example, due to adverse weather conditions such as heavy fog or rain) led to complete loss of the signal and a disruption of traffic. In a fixed modulation scheme, the microwave radio link had a binary state of either “'available” (on) or “unavailable” (off).

More technologically advanced microwave radios use an adaptive modulation scheme. In an adaptive modulation scheme, when the microwave link degrades due to adverse weather conditions, the radio changes its modulation scheme to a more robust scheme. The radio continues to broadcast but with less capacity. As a result, the radio can be in several capacity or bandwidth states, and not just on or off.

Microwave links are often used in Ethernet access ring (for example, G.8032 rings) topologies. In these ring topologies, capacity degradation can affect one side of the ring, while the other side is still operating at nominal throughput. In the case of congestion over the radio link, microwave transceivers prioritize the Ethernet traffic, and discard lower-priority frames.

By knowing the link capacity, Ethernet switches in the ring topology can optimize the traffic-forwarding rules, and select a more efficient direction over the ring to maximize traffic throughput. However, standard ring protection switching is triggered when the ring nodes detect a complete loss of continuity (for example, through the loss of Connectivity Fault Management's (CFM’s) connectivity connection messages).

In the case of microwave links with adaptive modulation, the control Operation, Administration, and Maintenance (OAM) protocols are unable to make best use of the available bandwidth due of the following OAM characteristics:

  • If the protocol used for failure detection is tagged as high-priority traffic, the OAM frames bypass the degraded (congested) microwave links and no protection switching is triggered.
  • If the protocol used for failure detection is tagged as low-priority traffic, then momentary congestion over the native Ethernet (that is, the nonmicrowave) links could lead to loss of continuity and spurious protection switching.

Even though the network topology must be provisioned with enough redundant bandwidth to handle a complete failure, in certain situations where the service committed information rate (CIR) is very low, forwarding as much excess traffic (above the CIR) as possible is important. Therefore, for those situations, treating bandwidth degradation as a complete failure is not desirable.

How to Configure G.8032 and CFM Support for Microwave Adaptive Bandwidth

Creating the Ethernet Microwave Event

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    event manager applet applet-name

    4.    event ethernet microwave sd {interface type number threshold threshold-bandwidth}

    5.    action action-id switch ring g8032 ring-name instance instance-id

    6.    event ethernet microwave clear-sd {interface type number}

    7.    action action-id switch ring g8032 clear ring-name instance {instance-id | all}

    8.    Repeat steps 4 through 7 for each Ethernet microwave event you want to create. Then proceed to step 9.

    9.    exit


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 event manager applet applet-name


    Example:
    Device(config)# event manager applet mw_ring_sd1
     

    Registers an applet with the Embedded Event Manager (EEM) and enters applet configuration mode.

     
    Step 4 event ethernet microwave sd {interface type number threshold threshold-bandwidth}


    Example:
    Device(config-applet)# event ethernet microwave sd interface gigabitethernet0/0/0 threshold 400
     
    Creates the Ethernet microwave signal degradation (SD) event.
    • After the event is created, use the action switch ring g8032 instance command at step 5 to specify the appropriate action to take on this event.
     
    Step 5 action action-id switch ring g8032 ring-name instance instance-id


    Example:
    Device(config-applet)# action 1 switch ring g8032 ringA instance 1
     

    Specifies the protocol switch action for an instance on a link of a G.8032 Ethernet Protection Ring (ERP).

     
    Step 6 event ethernet microwave clear-sd {interface type number}


    Example:
    Device(config-applet)# event ethernet microwave clear-sd interface gigabitethernet0/0/0
     
    Creates the Ethernet microwave event to be associated with bandwidth SD occurrences.
    • After the event is created, use the action switch ring g8032 clear instance command at step 7 to clear the SD occurrence and bring the ring back to the normal (idle) state.
     
    Step 7 action action-id switch ring g8032 clear ring-name instance {instance-id | all}


    Example:
    Device(config-applet)# action 1 switch ring g8032 clear ringA instance 1
     

    Specifies the action of clearing an SD occurrence on a link of a G.8032 Ethernet Protection Ring (ERP) topology.

     
    Step 8Repeat steps 4 through 7 for each Ethernet microwave event you want to create. Then proceed to step 9.

    Example:
    —
          		 
    Step 9 exit


    Example:
    Device(config-applet)# exit
     

    Exits applet configuration mode.

     

    Modifying Ethernet Microwave Event Settings

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type name

      4.    ethernet event microwave hold-off seconds

      5.    ethernet event microwave loss-threshold number-of-messages

      6.    ethernet event microwave wtr seconds

      7.    exit

      8.    show ethernet event microwave status [interface type number]

      9.    show ethernet event microwave statistics [interface type number]

      10.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 interface type name


      Example:
      Device(config)# interface gigabitethernet0/0/0
       

      Specifies an interface and enters interface configuration mode.

       
      Step 4 ethernet event microwave hold-off seconds


      Example:
      Device(config-if)# ethernet event microwave hold-off 30
       
      Specifies the microwave bandwidth degradation hold-off time, in seconds.
      • This time is used to prevent changes in the state of the network node as a result of signal degradation (SD) occurrences.
       
      Step 5 ethernet event microwave loss-threshold number-of-messages


      Example:
      Device(config-if)# ethernet event microwave loss-threshold 3
       

      Specifies the number of bandwidth Vendor-Specific Messages (VSM) sent from the microwave transceiver to the Cisco device.

      Once the link experiences signal degradation, the microwave transceiver sends periodic bandwidth VSM messages to the Cisco device until the bandwidth is fully restored. The interval of these messages is controlled by the microwave transceiver.

      This configuration specifies the continuous bandwidth VSM messages the Cisco device misses before declaring a signal recovery event.

       
      Step 6 ethernet event microwave wtr seconds


      Example:
      Device(config-if)# ethernet event microwave wtr 45
       
      Specifies the wait-to-restore (WTR) time, in seconds.
      • This time is used to prevent changes in the state of the network node as a result of recovery events after an SD occurrence.
       
      Step 7 exit


      Example:
      Device(config-if)# exit
       

      Exits interface configuration mode.

       
      Step 8 show ethernet event microwave status [interface type number]


      Example:
      Device# show ethernet event microwave status GigabitEthernet 0/0/2
       

      (Optional) Displays the microwave event status.

       
      Step 9 show ethernet event microwave statistics [interface type number]


      Example:
      Device# show ethernet event microwave statistics GigabitEthernet 0/0/2
       

      (Optional) Displays the microwave event statistics.

       
      Step 10 end


      Example:
      Device# end
       

      Returns to user EXEC mode.

       

      Configuration Examples for G.8032 and CFM Support for Microwave Adaptive Bandwidth

      Example: Configuring the Ethernet Microwave Event

      In this example, two Ethernet microwave events have been created, mw_ring_sdl1 and mw_ring_sd_2: 

      Device> enable
Device> configure terminal
Device(config)# event manager applet mw_ring_sd1
Device(config-applet)# event ethernet microwave sd interface gigabitethernet0/0/0 threshold 400
Device(config-applet)# action 1 switch ring g8032 ringA instance 1  
Device(config-applet)# exit
Device(config)# event manager applet mw_ring_sd2
Device(config-applet)# event ethernet microwave sd interface gigabitethernet0/0/0 threshold 400
Device(config-applet)# action 1 switch ring g8032 ringA instance 2  
Device(config-applet)# exit

      In this example, a microwave event has been configured that clears all the signal degradation (SD) events, as defined by the action switch ring g8032 clear instance all command: 

      Device> enable
Device> configure terminal
Device(config)# event manager applet mw_ring_clear_sd
Device(config-applet)# event ethernet microwave clear-sd interface gigabitethernet0/0/0 
Device(config-applet)# action 1 switch ring g8032 clear ringA instance all  
Device(config-applet)# exit

      Example: Verifying the Ethernet Microwave Event Configuration

      The following is sample output from the show ethernet event microwave status command where GigabitEthernet interface 0/0/2 has been specified. Use the command to confirm that the configuration is performing as intended. 

      Device# show ethernet event microwave status GigabitEthernet 0/0/2

Microwave Bandwidth Status for GigabitEthernet0/0/2
 State : Degraded
 Elapsed time in this state : 1:25:33
 Nominal Bandwidth : 512Mbps
 Current Bandwidth : 256Mbps
 Lowest Bandwidth Since Entering Degraded : 64Mbps
 Last VSM Received : Oct 27 14:06:19.983
 Sender Transmit Period : 1 second
 Sender Address : 01AB.CC00.1881
 Hold Timer : Not Running
 Restore Timer : Not Running
 Periodic Timer : 2333 msec <--Calculated using the configured loss-threshold value.
 Hold Time : 0 seconds      <--This is hold-off timer value.   
 Restore Time : 10 seconds  <--This is the wait-to-restore value.
 Loss-Threshold: 3

      The following is sample output from the show ethernet event microwave statistics command where GigabitEthernet interface 0/0/2 has been specified: 

      Device#show ethernet event microwave statistics GigabitEthernet 0/0/2

Microwave Bandwidth Statistics for GigabitEthernet0/0/2
 Total VSM Receive Count : 145
 Total VSM Drop Count : 0
 Number of transitions into Degraded state : 2

      Additional References for G.8032 and CFM Support for Microwave Adaptive Bandwidth

      Related Documents

      Related Topic

      Document Title

      Ethernet Connectivity Fault Management (CFM)

      Configuring Ethernet Connectivity Fault Management in a Service Provider Network or Cofiguring IEEE Standard-Compliant Ethernet CFM in a Service Provider Network”

      G.8032 Ethernet Ring Protection (ERP) administrative information and wiki

      ITU-T G.8032 Ethernet Ring Protection Switching

      http:/​/​docwiki.cisco.com/​wiki/​G.8032_​Ethernet_​Ring_​Protection_​(ERP)_​Administrative_​Procedures

      Operations, Administration, and Maintenance (OAM)

      Using Ethernet Operations, Administration, and Maintenance

      Carrier Ethernet commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

      Cisco IOS Carrier Ethernet Command Reference

      Cisco IOS commands: master list of commands with complete command syntax, command mode, command history, defaults, usage guidelines, and examples

      Cisco IOS Master Command List, All Releases

      Standards

      Standard

      Title

      ITU-T

      ITU-T Y.1731 OAM Mechanisms for Ethernet-Based Networks

      Technical Assistance

      Description

      Link

      The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

      Feature Information for G.8032 and CFM Support for Microwave Adaptive Bandwidth

      The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

      Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

      Table 1 Feature Information for G.8032 and CFM Support for Microwave Adaptive Bandwidth

      Feature Name

      Releases

      Feature Information

      G.8032 and CFM Support for Microwave Adaptive Bandwidth

      15.3(2)S

      The G.8032 and CFM Support for Microwave Adaptive Bandwidth feature extends the functionality of the G.8032 Ethernet Protection Ring (ERP) mechanism and Ethernet Connectivity Fault Management (CFM).

      This feature enables the G.8032 ERP mechanism to be used as a trigger in response to bandwidth degradation occurrences (such as a signal degradation [SD] indicator) on microwave links. Ethernet CFM interacts with the microwave transceiver to continuously check the quality and the bandwidth of the microwave link. When microwave link degradation (based on the configured service level agreement [SLA] in use) is detected, CFM notifies the G.8032 ERP mechanism, which in turn ensures that the degraded microwave link is bypassed and no longer used. The degraded microwave link can still be used by one or more of the G.8032 ERP instances. Only the affected G.8032 ERP instances are switched to alternate link.

      In Cisco IOS Release 15.3(2)S, support was added for the Cisco ASR 901 series Aggregation Services Router.

      The following commands were introduced or modified: action switch ring g8032 clear instance, action switch switch ring g8032 instance, clear ethernet event microwave data, clear ethernet event microwave statistics, debug ethernet event microwave, ethernet event microwave, event ethernet microwave clear-sd, event ethernet microwave sd, show ethernet event microwave statistics, and show ethernet event microwave status.