Carrier Ethernet Configuration Guide, Cisco IOS XE Release (ASR 903)
Using Ethernet Operations Administration and Maintenance
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Using Ethernet Operations Administration and Maintenance

Contents

Using Ethernet Operations Administration and Maintenance

Ethernet Operations, Administration, and Maintenance (OAM) is a protocol for installing, monitoring, and troubleshooting Ethernet metropolitan-area networks (MANs) and Ethernet WANs. It relies on a new, optional sublayer in the data link layer of the Open Systems Interconnection (OSI) model. The OAM features covered by this protocol are Discovery, Link Monitoring, Remote Fault Detection, Remote Loopback, and Cisco Proprietary Extensions.

The advent of Ethernet as a MAN and WAN technology has emphasized the necessity for integrated management for larger deployments. For Ethernet to extend into public MANs and WANs, it must be equipped with a new set of requirements on Ethernet’s traditional operations, which had been centered on enterprise networks only. The expansion of Ethernet technology into the domain of service providers, where networks are substantially larger and more complex than enterprise networks and the user-base is wider, makes operational management of link uptime crucial.

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.

Information About Using Ethernet Operations Administration and Maintenance

Ethernet OAM

Ethernet OAM is a protocol for installing, monitoring, and troubleshooting metro Ethernet networks and Ethernet WANs. It relies on a new, optional sublayer in the data link layer of the OSI model. Ethernet OAM can be implemented on any full-duplex point-to-point or emulated point-to-point Ethernet link. A system-wide implementation is not required; OAM can be deployed for part of a system; that is, on particular interfaces.

Normal link operation does not require Ethernet OAM. OAM frames, called OAM protocol data units (PDUs), use the slow protocol destination MAC address 0180.c200.0002. They are intercepted by the MAC sublayer and cannot propagate beyond a single hop within an Ethernet network.

Ethernet OAM is a relatively slow protocol with modest bandwidth requirements. The frame transmission rate is limited to a maximum of 10 frames per second; therefore, the impact of OAM on normal operations is negligible. However, when link monitoring is enabled, the CPU must poll error counters frequently. In this case, the required CPU cycles will be proportional to the number of interfaces that have to be polled.

Two major components, the OAM client and the OAM sublayer, make up Ethernet OAM. The following two sections describe these components.

OAM Client

The OAM client is responsible for establishing and managing Ethernet OAM on a link. The OAM client also enables and configures the OAM sublayer. During the OAM discovery phase, the OAM client monitors OAM PDUs received from the remote peer and enables OAM functionality on the link based on local and remote state as well as configuration settings. Beyond the discovery phase (at steady state), the OAM client is responsible for managing the rules of response to OAM PDUs and managing the OAM remote loopback mode.

OAM Sublayer

The OAM sublayer presents two standard IEEE 802.3 MAC service interfaces: one facing toward the superior sublayers, which include the MAC client (or link aggregation), and the other interface facing toward the subordinate MAC control sublayer. The OAM sublayer provides a dedicated interface for passing OAM control information and OAM PDUs to and from a client.

The OAM sublayer is made up of three components: control block, multiplexer, and packet parser (p-parser). Each component is described in the following sections.

Control Block

The control block provides the interface between the OAM client and other blocks internal to the OAM sublayer. The control block incorporates the discovery process, which detects the existence and capabilities of remote OAM peers. It also includes the transmit process that governs the transmission of OAM PDUs to the multiplexer and a set of rules that govern the receipt of OAM PDUs from the p-parser.

Multiplexer

The multiplexer manages frames generated (or relayed) from the MAC client, control block, and p-parser. The multiplexer passes through frames generated by the MAC client untouched. It passes OAM PDUs generated by the control block to the subordinate sublayer; for example, the MAC sublayer. Similarly, the multiplexer passes loopback frames from the p-parser to the same subordinate sublayer when the interface is in OAM remote loopback mode.

P-Parser

The p-parser classifies frames as OAM PDUs, MAC client frames, or loopback frames and then dispatches each class to the appropriate entity. OAM PDUs are sent to the control block. MAC client frames are passed to the superior sublayer. Loopback frames are dispatched to the multiplexer.

Benefits of Ethernet OAM

Ethernet OAM provides the following benefits:

  • Competitive advantage for service providers
  • Standardized mechanism to monitor the health of a link and perform diagnostics

Cisco Implementation of Ethernet OAM

The Cisco implementation of Ethernet OAM consists of the Ethernet OAM shim and the Ethernet OAM module.

The Ethernet OAM shim is a thin layer that connects the Ethernet OAM module and the platform code. It is implemented in the platform code (driver). The shim also communicates port state and error conditions to the Ethernet OAM module via control signals.

The Ethernet OAM module, implemented within the control plane, handles the OAM client as well as control block functionality of the OAM sublayer. This module interacts with the CLI and Simple Network Management Protocol (SNMP)/programmatic interface via control signals. In addition, this module interacts with the Ethernet OAM shim through OAM PDU flows.

OAM Features

The OAM features as defined by IEEE 802.3ah, Ethernet in the First Mile , are discovery, Link Monitoring, Remote Fault Detection, Remote Loopback, and Cisco Proprietary Extensions.

Discovery

Discovery is the first phase of Ethernet OAM and it identifies the devices in the network and their OAM capabilities. Discovery uses information OAM PDUs. During the discovery phase, the following information is advertised within periodic information OAM PDUs:

  • OAM mode--Conveyed to the remote OAM entity. The mode can be either active or passive and can be used to determine device functionality.
  • OAM configuration (capabilities)--Advertises the capabilities of the local OAM entity. With this information a peer can determine what functions are supported and accessible; for example, loopback capability.
  • OAM PDU configuration--Includes the maximum OAM PDU size for receipt and delivery. This information along with the rate limiting of 10 frames per second can be used to limit the bandwidth allocated to OAM traffic.
  • Platform identity--A combination of an organization unique identifier (OUI) and 32-bits of vendor-specific information. OUI allocation, controlled by the IEEE, is typically the first three bytes of a MAC address.

Discovery includes an optional phase in which the local station can accept or reject the configuration of the peer OAM entity. For example, a node may require that its partner support loopback capability to be accepted into the management network. These policy decisions may be implemented as vendor-specific extensions.

Link Monitoring

Link monitoring in Ethernet OAM detects and indicates link faults under a variety of conditions. Link monitoring uses the event notification OAM PDU and sends events to the remote OAM entity when there are problems detected on the link. The error events include the following:

  • Error Symbol Period (error symbols per second)--The number of symbol errors that occurred during a specified period exceeded a threshold. These errors are coding symbol errors.
  • Error Frame (error frames per second)--The number of frame errors detected during a specified period exceeded a threshold.
  • Error Frame Period (error frames per n frames)--The number of frame errors within the last n frames has exceeded a threshold.
  • Error Frame Seconds Summary (error seconds per m seconds)--The number of error seconds (1-second intervals with at least one frame error) within the last m seconds has exceeded a threshold.

Since IEEE 802.3ah OAM does not provide a guaranteed delivery of any OAM PDU, the event notification OAM PDU may be sent multiple times to reduce the probability of a lost notification. A sequence number is used to recognize duplicate events.

Remote Failure Indication

Faults in Ethernet connectivity that are caused by slowly deteriorating quality are difficult to detect. Ethernet OAM provides a mechanism for an OAM entity to convey these failure conditions to its peer via specific flags in the OAM PDU. The following failure conditions can be communicated:

  • Link Fault--Loss of signal is detected by the receiver; for instance, the peer’s laser is malfunctioning. A link fault is sent once per second in the information OAM PDU. Link fault applies only when the physical sublayer is capable of independently transmitting and receiving signals.
  • Dying Gasp--An unrecoverable condition has occurred; for example, when an interface is shut down. This type of condition is vendor specific. A notification about the condition may be sent immediately and continuously.
  • Critical Event--An unspecified critical event has occurred. This type of event is vendor specific. A critical event may be sent immediately and continuously.

Remote Loopback

An OAM entity can put its remote peer into loopback mode using the loopback control OAM PDU. Loopback mode helps an administrator ensure the quality of links during installation or when troubleshooting. In loopback mode, every frame received is transmitted back on the same port except for OAM PDUs and pause frames. The periodic exchange of OAM PDUs must continue during the loopback state to maintain the OAM session.

The loopback command is acknowledged by responding with an information OAM PDU with the loopback state indicated in the state field. This acknowledgement allows an administrator, for example, to estimate if a network segment can satisfy a service-level agreement. Acknowledgement makes it possible to test delay, jitter, and throughput.

When an interface is set to the remote loopback mode the interface no longer participates in any other Layer 2 or Layer 3 protocols; for example Spanning Tree Protocol (STP) or Open Shortest Path First (OSPF). The reason is that when two connected ports are in a loopback session, no frames other than the OAM PDUs are sent to the CPU for software processing. The non-OAM PDU frames are either looped back at the MAC level or discarded at the MAC level.

From a user’s perspective, an interface in loopback mode is in a link-up state.

Cisco Vendor-Specific Extensions

Ethernet OAM allows vendors to extend the protocol by allowing them to create their own type-length-value (TLV) fields.

OAM Messages

Ethernet OAM messages or OAM PDUs are standard length, untagged Ethernet frames within the normal frame length bounds of 64 to 1518 bytes. The maximum OAM PDU frame size exchanged between two peers is negotiated during the discovery phase.

OAM PDUs always have the destination address of slow protocols (0180.c200.0002) and an Ethertype of 8809. OAM PDUs do not go beyond a single hop and have a hard-set maximum transmission rate of 10 OAM PDUs per second. Some OAM PDU types may be transmitted multiple times to increase the likelihood that they will be successfully received on a deteriorating link.

Four types of OAM messages are supported:

  • Information OAM PDU--A variable-length OAM PDU that is used for discovery. This OAM PDU includes local, remote, and organization-specific information.
  • Event notification OAM PDU--A variable-length OAM PDU that is used for link monitoring. This type of OAM PDU may be transmitted multiple times to increase the chance of a successful receipt; for example, in the case of high-bit errors. Event notification OAM PDUs also may include a time stamp when generated.
  • Loopback control OAM PDU--An OAM PDU fixed at 64 bytes in length that is used to enable or disable the remote loopback command.
  • Vendor-specific OAM PDU--A variable-length OAM PDU that allows the addition of vendor-specific extensions to OAM.

IEEE 802.3ah Link Fault RFI Support

The IEEE 802.3ah Link Fault RFI Support feature provides a per-port configurable option that moves a port into a blocking state when an OAM PDU control request packet is received with the Link Fault Status flag set. In the blocking state, the port can continue to receive OAM PDUs, detect remote link status, and automatically recover when the remote link becomes operational. When an OAM PDU is received with the Link Fault Status flag set to zero or FALSE, the port is enabled and all VLANs configured on the port are set to “forwarding.”


Note


If you configure the Ethernet OAM timeout period to be the minimum allowable value of 2 seconds, the Ethernet OAM session may be dropped briefly when the port transitions from blocked to unblocked. This action will not occur by default; the default timeout value is 5 seconds.


Before the release of the IEEE 802.3ah Link Fault RFI Support feature, when an OAM PDU control request packet was received with the Link Fault Status flag set, one of three actions was taken:

  • The port was put in the error-disable state, meaning that the port did not send or receive packets, including Bridge Protocol Data Units (BPDU) packets. In the error-disable state, a link can automatically recover after the error-disable timeout period but cannot recover automatically when the remote link becomes operational.
  • A warning message was displayed or logged, and the port remained operational.
  • The Link Fault Status flag was ignored.

A new keyword, error-block-interface, for the CLI command ethernet oam remote-failure action is introduced with the IEEE 802.3ah Link Fault RFI Support feature. For detailed information about this command, see the Cisco IOS Carrier Ethernet Command Reference.

Ethernet Connectivity Fault Management

Ethernet connectivity fault management (CFM) is an end-to-end per-service-instance Ethernet layer OAM protocol that includes proactive connectivity monitoring, fault verification, and fault isolation. End to end can be provider edge (PE) to PE or customer edge (CE) to CE. Per service instance means per VLAN.

For more information about Ethernet CFM, see Ethernet Connectivity Fault Management .

High Availability Features Supported by 802.3ah

In access and service provider networks using Ethernet technology, High Availability (HA) is a requirement, especially on Ethernet OAM components that manage Ethernet virtual circuit (EVC) connectivity. End-to-end connectivity status information is critical and must be maintained on a hot standby Route Switch Processor (RSP) (a standby RSP that has the same software image as the active RSP and supports synchronization of line card, protocol, and application state information between RSPs for supported features and protocols). End-to-end connectivity status is maintained on the CE, PE, and access aggregation PE (uPE) network nodes based on information received by protocols such as CFM and 802.3ah. This status information is used to either stop traffic or switch to backup paths when an EVC is down. Metro Ethernet clients (for example, CFM and 802.3ah) maintain configuration data and dynamic data, which is learned through protocols. Every transaction involves either accessing or updating data among the various databases. If the databases are synchronized across active and standby modules, the RSPs are transparent to clients.

Cisco infrastructure provides various component application program interfaces (APIs) for clients that are helpful in maintaining a hot standby RSP. Metro Ethernet HA clients (such as, HA/ISSU, CFM HA/ISSU, 802.3ah HA/ISSU) interact with these components, update the databases, and trigger necessary events to other components.

Benefits of 802.3ah HA

  • Elimination of network downtime for Cisco software image upgrades, resulting in higher availability
  • Elimination of resource scheduling challenges associated with planned outages and late night maintenance windows
  • Accelerated deployment of new services and applications and faster implementation of new features, hardware, and fixes due to the elimination of network downtime during upgrades
  • Reduced operating costs due to outages while delivering higher service levels due to the elimination of network downtime during upgrades

NSF SSO Support in 802.3ah OAM

The redundancy configurations Stateful Switchover (SSO) and Nonstop Forwarding (NSF) are both supported in Ethernet OAM and are automatically enabled. A switchover from an active to a standby Route Switch Processor (RSP) occurs when the active RSP fails, is removed from the networking device, or is manually taken down for maintenance. NSF interoperates with the SSO feature to minimize network downtime following a switchover. The primary function of Cisco NSF is to continue forwarding IP packets following an RSP switchover.

For detailed information about the SSO feature, see the “Configuring Stateful Switchover” module of the High Availability Configuration Guide. For detailed information about the NSF feature, see the “Configuring Cisco Nonstop Forwarding” module of the High Availability Configuration Guide.

ISSU Support in 802.3ah OAM

Cisco In-Service Software Upgrades (ISSUs) allow you to perform a Cisco software upgrade or downgrade without disrupting packet flow. ISSU is automatically enabled in 802.3ah. OAM performs a bulk update and a runtime update of the continuity check database to the standby Route Switch Processor (RSP), including adding, deleting, or updating a row. This checkpoint data requires ISSU capability to transform messages from one release to another. All the components that perform active RSP to standby RSP updates using messages require ISSU support.

ISSU lowers the impact that planned maintenance activities have on network availability by allowing software changes while the system is in service. For detailed information about ISSU, see the “Performing an In Service Software Upgrade” module of the High Availability Configuration Guide.

How to Set Up and Configure Ethernet Operations Administration and Maintenance

Enabling Ethernet OAM on an Interface

Ethernet OAM is by default disabled on an interface.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    interface type number

    4.    ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]

    5.    exit


DETAILED STEPS
      Command or Action Purpose
    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 number


    Example:
    Device(config)# interface gigabitethernet 3/8
     

    Specifies an interface and enters interface configuration mode.

     
    Step 4 ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]


    Example:
    Device(config-if)# ethernet oam 
     

    Enables Ethernet OAM.

     
    Step 5 exit


    Example:
    Device(config-if)# exit
     

    Returns to global configuration mode.

     

    Disabling and Enabling a Link Monitoring Session

    Link monitoring is enabled by default when you enable Ethernet OAM. Perform these tasks to disable and enable link monitoring sessions:

    Disabling a Link Monitoring Session

    Perform this task to disable a link monitoring session.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface type number

      4.    ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]

      5.    no ethernet oam link-monitor supported

      6.    exit


    DETAILED STEPS
        Command or Action Purpose
      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 number


      Example:
      Device(config)# interface gigabitEthernet 3/8
       

      Specifies an interface and enters interface configuration mode.

       
      Step 4 ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]


      Example:
      Device(config-if)# ethernet oam 
       

      Enables Ethernet OAM.

       
      Step 5 no ethernet oam link-monitor supported


      Example:
      Device(config-if)# no ethernet oam link-monitor supported
       

      Disables link monitoring on the interface.

       
      Step 6 exit


      Example:
      Device(config-if)# exit
       

      Returns to global configuration mode.

       

      Enabling a Link Monitoring Session

      Perform this task to reenable a link monitoring session after it was previously disabled.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    interface type number

        4.    ethernet oam link-monitor supported

        5.    exit


      DETAILED STEPS
          Command or Action Purpose
        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 number


        Example:
        Device(config)# interface gigabitEthernet 3/8
         

        Specifies an interface and enters interface configuration mode.

         
        Step 4 ethernet oam link-monitor supported


        Example:
        Device(config-if)# ethernet oam link-monitor supported
         

        Enables link monitoring on the interface.

         
        Step 5 exit


        Example:
        Device(config-if)# exit
         

        Returns to global configuration mode.

         

        Stopping and Starting Link Monitoring Operations

        Link monitoring operations start automatically when Ethernet OAM is enabled on an interface. When link monitoring operations are stopped, the interface does not actively send or receive event notification OAM PDUs. The tasks in this section describe how to stop and start link monitoring operations.

        Stopping Link Monitoring Operations

        Perform this task to stop link monitoring operations.

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    interface type number

          4.    ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]

          5.    no ethernet oam link-monitor on

          6.    exit


        DETAILED STEPS
            Command or Action Purpose
          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 number


          Example:
          Device(config)# interface gigabitethernet 3/8
           

          Specifies an interface and enters interface configuration mode.

           
          Step 4 ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]


          Example:
          Device(config-if)# ethernet oam 
           

          Enables Ethernet OAM.

           
          Step 5 no ethernet oam link-monitor on


          Example:
          Device(config-if)# no ethernet oam link-monitor on
           

          Stops link monitoring operations.

           
          Step 6 exit


          Example:
          Device(config-if)# exit
           

          Returns to global configuration mode.

           

          Starting Link Monitoring Operations

          Perform this task to start link monitoring operations.

          SUMMARY STEPS

            1.    enable

            2.    configure terminal

            3.    interface type number

            4.    ethernet oam link-monitor on

            5.    exit


          DETAILED STEPS
              Command or Action Purpose
            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 number


            Example:
            Device(config)# interface gigabitethernet 3/8
             

            Specifies an interface and enters interface configuration mode.

             
            Step 4 ethernet oam link-monitor on


            Example:
            Device(config-if)# ethernet oam link-monitor on
             

            Starts link monitoring operations.

             
            Step 5 exit


            Example:
            Device(config-if)# exit
             

            Returns to global configuration mode.

             

            Configuring Link Monitoring Options

            Perform this optional task to specify link monitoring options. Steps 4 through 10 can be performed in any sequence.

            SUMMARY STEPS

              1.    enable

              2.    configure terminal

              3.    interface type number

              4.    ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]

              5.    ethernet oam link-monitor high-threshold action error-disable-interface

              6.    ethernet oam link-monitor frame {threshold {high {none | high-frames} | low low-frames} | window milliseconds}

              7.    ethernet oam link-monitor frame-period {threshold {high {none | high-frames} | low low-frames} | window frames}

              8.    ethernet oam link-monitor frame-seconds {threshold {high {none | high-frames} | low low-frames} | window milliseconds}

              9.    ethernet oam link-monitor receive-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}

              10.    ethernet oam link-monitor transmit-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}

              11.    ethernet oam link-monitor symbol-period {threshold {high {none | high-symbols} | low low-symbols} | window symbols}

              12.    exit


            DETAILED STEPS
                Command or Action Purpose
              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 number


              Example:
              Device(config)# interface gigabitEthernet 3/8
               

              Identifies the interface and enters interface configuration mode.

               
              Step 4 ethernet oam [max-rate oampdus | min-rate num-seconds| mode {active | passive} | timeout seconds]


              Example:
              Device(config-if)# ethernet oam 
               

              Enables Ethernet OAM.

               
              Step 5 ethernet oam link-monitor high-threshold action error-disable-interface


              Example:
              Device(config-if)# ethernet oam link-monitor high-threshold action error-disable-interface 
               

              Configures an error-disable function on an Ethernet OAM interface when a high threshold for an error is exceeded.

               
              Step 6 ethernet oam link-monitor frame {threshold {high {none | high-frames} | low low-frames} | window milliseconds}


              Example:
              Device(config-if)# ethernet oam link-monitor frame window 399
               

              Configures a number for error frames that when reached triggers an action.

               
              Step 7 ethernet oam link-monitor frame-period {threshold {high {none | high-frames} | low low-frames} | window frames}


              Example:
              Device(config-if)# ethernet oam link-monitor frame-period threshold high 599
               

              Configures a number of frames to be polled.

              Frame period is a user-defined parameter.

               
              Step 8 ethernet oam link-monitor frame-seconds {threshold {high {none | high-frames} | low low-frames} | window milliseconds}


              Example:
              Device(config-if)# ethernet oam link-monitor frame-seconds window 699
               

              Configures a period of time in which error frames are counted.

               
              Step 9 ethernet oam link-monitor receive-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}


              Example:
              Device(config-if)# ethernet oam link-monitor receive-crc window 99
               

              Configures an Ethernet OAM interface to monitor ingress frames with cyclic redundancy check (CRC) errors for a period of time.

               
              Step 10 ethernet oam link-monitor transmit-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}


              Example:
              Device(config-if)# ethernet oam link-monitor transmit-crc threshold low 199
               

              Configures an Ethernet OAM interface to monitor egress frames with CRC errors for a period of time.

               
              Step 11 ethernet oam link-monitor symbol-period {threshold {high {none | high-symbols} | low low-symbols} | window symbols}


              Example:
              Device(config-if)# ethernet oam link-monitor symbol-period threshold high 299
               

              Configures a threshold or window for error symbols, in number of symbols.

               
              Step 12 exit


              Example:
              Device(config-if)# exit
               

              Returns to global configuration mode.

               

              Example

              Device# configure terminal
               
              Enter configuration commands, one per line.  End with CNTL/Z.
               
              Device(config)# interface gigabitEthernet 3/8
              Device(config-if)#
              Device(config-if)# ethernet oam
               
              Device(config-if)# ethernet oam link-monitor high-threshold action error-disable-interface
              Device(config-if)# ethernet oam link-monitor frame window 399
              Device(config-if)# ethernet oam link-monitor frame-period threshold high 599
              Device(config-if)# ethernet oam link-monitor frame-seconds window 699
              Device(config-if)# ethernet oam link-monitor receive-crc window 99
              Device(config-if)# ethernet oam link-monitor transmit-crc threshold low 199
              Device(config-if)# ethernet oam link-monitor symbol-period threshold high 299
              Device(config-if)# exit
              Device# show running-config
               
              Building configuration...
              Current configuration : 5613 bytes
              !
              !
              version 12.2
              !
              !
              .
              .
              .
              !
              !
              interface GigabitEthernet3/8
               no ip address
               ethernet oam link-monitor high-threshold action error-disable-interface
               ethernet oam link-monitor frame window 399
               ethernet oam link-monitor frame-period threshold high 599
               ethernet oam link-monitor frame-seconds window 699
               ethernet oam link-monitor receive-crc window 99
               ethernet oam link-monitor transmit-crc threshold low 199
               ethernet oam link-monitor symbol-period threshold high 299
               ethernet oam

              Configuring Global Ethernet OAM Options Using a Template

              Perform this task to create a template to use for configuring a common set of options on multiple Ethernet OAM interfaces. Steps 4 through 10 are optional and can be performed in any sequence. These steps may also be repeated to configure different options.

              SUMMARY STEPS

                1.    enable

                2.    configure terminal

                3.    template template-name

                4.    ethernet oam link-monitor receive-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}

                5.    ethernet oam link-monitor transmit-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}

                6.    ethernet oam link-monitor symbol-period {threshold {high {none | high-symbols} | low low-symbols} | window symbols}

                7.    ethernet oam link-monitor high-threshold action error-disable-interface

                8.    ethernet oam link-monitor frame {threshold {high {none | high-frames} | low low-frames} | window milliseconds}

                9.    ethernet oam link-monitor frame-period {threshold {high {none | high-frames} | low low-frames} | window frames}

                10.    ethernet oam link-monitor frame-seconds {threshold {high {none | high-frames} | low low-frames} | window milliseconds}

                11.    exit

                12.    interface type number

                13.    source template template-name

                14.    exit

                15.    exit

                16.    show running-config


              DETAILED STEPS
                  Command or Action Purpose
                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 template template-name


                Example:
                Device(config)# template oam-temp
                 

                Configures a template and enters template configuration mode.

                 
                Step 4 ethernet oam link-monitor receive-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}


                Example:
                Device(config-template)# ethernet oam link-monitor receive-crc window 99
                 

                Configures an Ethernet OAM interface to monitor ingress frames with CRC errors for a period of time.

                 
                Step 5 ethernet oam link-monitor transmit-crc {threshold {high {high-frames | none} | low low-frames} | window milliseconds}


                Example:
                Device(config-template)# ethernet oam link-monitor transmit-crc threshold low 199
                 

                Configures an Ethernet OAM interface to monitor egress frames with CRC errors for a period of time.

                 
                Step 6 ethernet oam link-monitor symbol-period {threshold {high {none | high-symbols} | low low-symbols} | window symbols}


                Example:
                Device(config-template)# ethernet oam link-monitor symbol-period threshold high 299
                 

                Configures a threshold or window for error symbols, in number of symbols.

                 
                Step 7 ethernet oam link-monitor high-threshold action error-disable-interface


                Example:
                Device(config-template)# ethernet oam link-monitor high-threshold action error-disable-interface 
                 

                Configures an error-disable function on an Ethernet OAM interface when a high threshold for an error is exceeded.

                 
                Step 8 ethernet oam link-monitor frame {threshold {high {none | high-frames} | low low-frames} | window milliseconds}


                Example:
                Device(config-template)# ethernet oam link-monitor frame window 399
                 

                Configures a number for error frames that when reached triggers an action.

                 
                Step 9 ethernet oam link-monitor frame-period {threshold {high {none | high-frames} | low low-frames} | window frames}


                Example:
                Device(config-template)# ethernet oam link-monitor frame-period threshold high 599
                 

                Configures a number of frames to be polled.

                Frame period is a user-defined parameter.

                 
                Step 10 ethernet oam link-monitor frame-seconds {threshold {high {none | high-frames} | low low-frames} | window milliseconds}


                Example:
                Device(config-template)# ethernet oam link-monitor frame-seconds window 699
                 

                Configures a period of time in which error frames are counted.

                 
                Step 11 exit


                Example:
                Device(config-template)# exit
                 

                Returns to global configuration mode.

                 
                Step 12 interface type number


                Example:
                Device(config)# interface gigabitEthernet 3/8
                 

                Identifies the interface on which to use the template and enters interface configuration mode.

                 
                Step 13 source template template-name


                Example:
                Device(config-if)# source template oam-temp
                 

                Applies to the interface the options configured in the template.

                 
                Step 14 exit


                Example:
                Device(config-if)# exit
                 

                Returns to global configuration mode.

                 
                Step 15 exit


                Example:
                Device(config)# exit
                 

                Returns to privileged EXEC mode.

                 
                Step 16 show running-config


                Example:
                Device# show running-config
                 

                Displays the updated running configuration.

                 

                Configuring a Port for Link Fault RFI Support

                Perform this task to put a port into a blocking state when an OAM PDU control request packet is received with the Link Fault Status flag set.

                SUMMARY STEPS

                  1.    enable

                  2.    configure terminal

                  3.    interface type number

                  4.    ethernet oam remote-failure {critical-event | dying-gasp | link-fault} action {error-block-interface | error-disable-interface}

                  5.    exit


                DETAILED STEPS
                    Command or Action Purpose
                  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 number


                  Example:
                  Device(config)# interface fastethernet 1/2
                   

                  Enters interface configuration mode.

                   
                  Step 4 ethernet oam remote-failure {critical-event | dying-gasp | link-fault} action {error-block-interface | error-disable-interface}


                  Example:
                  Device(config-if)# ethernet oam remote-failure critical-event action error-block-interface
                   

                  Sets the interface to the blocking state when a critical event occurs.

                   
                  Step 5 exit


                  Example:
                  Device(config-if)# exit
                   

                  Returns to global configuration mode.

                   

                  Configuration Examples for Ethernet Operations Administration and Maintenance

                  The following example shows how to configure Ethernet OAM options using a template and overriding that configuration by configuring an interface. In this example, the network supports a Gigabit Ethernet interface between the customer edge device and provider edge device.

                  ! Configure a global OAM template for both PE and CE configuration.
                  !
                  Device(config)# template oam
                  Device(config-template)# ethernet oam link-monitor symbol-period threshold low 10
                  Device(config-template)# ethernet oam link-monitor symbol-period threshold high 100
                  Device(config-template)# ethernet oam link-monitor frame window 100
                  Device(config-template)# ethernet oam link-monitor frame threshold low 10
                  Device(config-template)# ethernet oam link-monitor frame threshold high 100
                  Device(config-template)# ethernet oam link-monitor frame-period window 100
                  Device(config-template)# ethernet oam link-monitor frame-period threshold low 10
                  Device(config-template)# ethernet oam link-monitor frame-period threshold high 100
                  Device(config-template)# ethernet oam link-monitor frame-seconds window 1000
                  Device(config-template)# ethernet oam link-monitor frame-seconds threshold low 10
                  Device(config-template)# ethernet oam link-monitor frame-seconds threshold high 100
                  Device(config-template)# ethernet oam link-monitor receive-crc window 100
                  Device(config-template)# ethernet oam link-monitor receive-crc threshold high 100
                  Device(config-template)# ethernet oam link-monitor transmit-crc window 100
                  Device(config-template)# ethernet oam link-monitor transmit-crc threshold high 100
                  Device(config-template)# ethernet oam remote-failure dying-gasp action 
                  error-disable-interface
                  Device(config-template)# exit
                  !
                  ! Enable Ethernet OAM on the CE interface
                  !
                  Device(config)# interface gigabitethernet 4/1/1
                  Device(config-if)# ethernet oam
                  !
                  ! Apply the global OAM template named "oam" to the interface.
                  !
                  Device(config-if)# source template oam
                  !
                  ! Configure any interface-specific link monitoring commands to override the template configuration. The following example disables the high threshold link monitoring for receive CRC errors.
                  !
                  Device(config-if)# ethernet oam link-monitor receive-crc threshold high none
                  !
                  ! Enable Ethernet OAM on the PE interface
                  !
                  Device(config)# interface gigabitethernet 8/1/1
                  Device(config-if)# ethernet oam
                  !
                  ! Apply the global OAM template named "oam" to the interface.
                  !
                  Device(config-if)# source template oam
                  

                  The following examples show how to verify various Ethernet OAM configurations and activities.

                  Verifying an OAM Session

                  The following example shows that the local OAM client, Gigabit Ethernet interface Gi6/1/1, is in session with a remote client with MAC address 0012.7fa6.a700 and OUI 00000C, which is the OUI for Cisco. The remote client is in active mode and has established capabilities for link monitoring and remote loopback for the OAM session.

                  Device# show ethernet oam summary
                  Symbols:          * - Master Loopback State,  # - Slave Loopback State
                  Capability codes: L - Link Monitor,  R - Remote Loopback
                                    U - Unidirection,  V - Variable Retrieval
                    Local                       Remote
                  Interface       MAC Address    OUI    Mode    Capability
                   Gi6/1/1       0012.7fa6.a700 00000C active      L R 

                  Verifying OAM Discovery Status

                  The following example shows how to verify OAM discovery status of a local client and a remote peer:

                  Device# show ethernet oam discovery interface gigabitethernet6/1/1
                  GigabitEthernet6/1/1
                  Local client
                  ------------
                    Administrative configurations:
                      Mode:              active
                      Unidirection:      not supported
                      Link monitor:      supported (on)
                      Remote loopback:   not supported
                      MIB retrieval:     not supported
                      Mtu size:          1500
                    Operational status:
                  Port status:       operational
                      Loopback status:   no loopback
                      PDU permission:    any
                      PDU revision:      1
                  Remote client
                  -------------
                    MAC address: 0030.96fd.6bfa
                    Vendor(oui): 0x00 0x00 0x0C (cisco)
                    Administrative configurations:
                      Mode:              active
                     Unidirection:      not supported
                     Link monitor:      supported
                     Remote loopback:   not supported
                     MIB retrieval:     not supported
                     Mtu size:          1500

                  Verifying Information OAMPDU and Fault Statistics

                  The following example shows how to verify statistics for information OAM PDUs and local and remote faults:

                  Device# show ethernet oam statistics interface gigabitethernet6/1/1
                  GigabitEthernet6/1/1
                  Counters:
                  ---------
                  Information OAMPDU Tx                   : 588806
                  Information OAMPDU Rx                   : 988
                  Unique Event Notification OAMPDU Tx     : 0
                  Unique Event Notification OAMPDU Rx     : 0
                  Duplicate Event Notification OAMPDU TX  : 0
                  Duplicate Event Notification OAMPDU RX  : 0
                  Loopback Control OAMPDU Tx              : 1
                  Loopback Control OAMPDU Rx              : 0
                  Variable Request OAMPDU Tx              : 0
                  Variable Request OAMPDU Rx              : 0
                  Variable Response OAMPDU Tx             : 0
                  Variable Response OAMPDU Rx             : 0
                  Cisco OAMPDU Tx                         : 4
                  Cisco OAMPDU Rx                         : 0
                  Unsupported OAMPDU Tx                   : 0
                  Unsupported OAMPDU Rx                   : 0
                  Frames Lost due to OAM                  : 0
                  Local Faults:
                  -------------
                  0 Link Fault records
                  2 Dying Gasp records
                  Total dying gasps       : 4
                  Time stamp              : 00:30:39
                  Total dying gasps       : 3
                  Time stamp              : 00:32:39
                  0 Critical Event records
                  Remote Faults:
                  --------------
                  0 Link Fault records
                  0 Dying Gasp records
                  0 Critical Event records
                  Local event logs:
                  -----------------
                  0 Errored Symbol Period records
                  0 Errored Frame records
                  0 Errored Frame Period records
                  0 Errored Frame Second records
                  Remote event logs:
                  ------------------
                  0 Errored Symbol Period records
                  0 Errored Frame records
                  0 Errored Frame Period records
                  0 Errored Frame Second records

                  Verifying Link Monitoring Configuration and Status

                  The following example shows how to verify link monitoring configuration and status on the local client. The highlighted Status field in the example shows that link monitoring status is supported and enabled (on).

                  Device# show ethernet oam status interface gigabitethernet6/1/1
                  GigabitEthernet6/1/1
                  General
                  -------
                    Mode:                  active
                    PDU max rate:          10 packets per second
                    PDU min rate:          1 packet per 1 second
                    Link timeout:          5 seconds
                    High threshold action: no action
                  Link Monitoring
                  ---------------
                    Status: supported (on)
                    Symbol Period Error
                      Window:              1 million symbols
                      Low threshold:       1 error symbol(s)
                      High threshold:      none
                    Frame Error
                      Window:              10 x 100 milliseconds
                      Low threshold:       1 error frame(s)
                      High threshold:      none
                  Frame Period Error
                      Window:              1 x 100,000 frames
                      Low threshold:       1 error frame(s)
                      High threshold:      none
                    Frame Seconds Error
                      Window:              600 x 100 milliseconds
                      Low threshold:       1 error second(s)
                      High threshold:      none

                  Verifying Status of a Remote OAM Client

                  The following example shows that the local client interface Gi6/1/1 is connected to a remote client. Note the values in the Mode and Capability fields.

                  Device# show ethernet oam summary
                  Symbols:          * - Master Loopback State,  # - Slave Loopback State
                  Capability codes: L - Link Monitor,  R - Remote Loopback
                                    U - Unidirection,  V - Variable Retrieval
                    Local                       Remote
                  Interface       MAC Address    OUI    Mode    Capability
                   Gi6/1/1       0012.7fa6.a700 00000C active      L R 

                  Additional References

                  Related Documents

                  Related Topic

                  Document Title

                  Ethernet CFM

                  “Configuring Ethernet Connectivity Fault Management in a Service Provider Network” module in the Carrier Ethernet Configuration Guide

                  NSF SSO Support in 802.3ah OAM

                  “Configuring Stateful Switchover” module in the High Availability Configuration Guide and “Configuring Nonstop Forwarding” in the High Availability Configuration Guide

                  ISSU Support in 802.3ah OAM

                  “Configuring In Service Software Upgrades" module in the High Availability Configuration Guide

                  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

                  Configuring CFM over an EFP Interface with the Cross Connect feature on the Cisco ASR 903 Router

                  Configuring the CFM over EFP Interface with Cross Connect Feature

                  Configuring Ethernet Virtual Connections on the Cisco ASR 903 Router

                  Configuring Ethernet Virtual Connections on the Cisco ASR 903 Router

                  Standards

                  Standard

                  Title

                  IEEE Draft P802.3ah/D3.3

                  Ethernet in the First Mile - Amendment

                  IETF VPLS OAM

                  L2VPN OAM Requirements and Framework

                  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 Using Ethernet Operations Administration and Maintenance

                  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 Using Ethernet Operations, Administration, and Maintenance

                  Feature Name

                  Releases

                  Feature Information

                  Ethernet Operations, Administration, and Maintenance

                  12.4(15)T

                  Ethernet OAM is a protocol for installing, monitoring, and troubleshooting metro Ethernet networks and Ethernet WANs. It relies on a new, optional sublayer in the data link layer of the OSI model. The OAM features covered by this protocol are Discovery, Link Monitoring, Remote Fault Detection, Remote Loopback, and Cisco Proprietary Extensions.

                  The Ethernet Operations, Administration, and Maintenance feature was integrated into Cisco IOS Release 12.4(15)T.

                  The following commands were introduced or modified: clear ethernet oam statistics, debug ethernet oam, ethernet oam, ethernet oam link-monitor frame, ethernet oam link-monitor frame-period, ethernet oam link-monitor frame-seconds, ethernet oam link-monitor high-threshold action, ethernet oam link-monitor on, ethernet oam link-monitor receive-crc, ethernet oam link-monitor supported, ethernet oam link-monitor symbol-period, ethernet oam link-monitor transmit-crc, ethernet oam remote-loopback, ethernet oam remote-loopback (interface), show ethernet oam discovery, show ethernet oam statistics, show ethernet oam status, show ethernet oam summary, source template (eoam), template (eoam).