Carrier Ethernet Configuration Guide, Cisco IOS XE Release 3S
Using Link Layer Discovery Protocol in Multivendor Networks
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Using Link Layer Discovery Protocol in Multivendor Networks

Contents

Using Link Layer Discovery Protocol in Multivendor Networks

Link Layer Discovery Protocol (LLDP), standardized by the IEEE as part of 802.1ab, enables standardized discovery of nodes, which in turn facilitates future applications of standard management tools such as Simple Network Management Protocol (SNMP) in multivendor networks. Using standard management tools makes physical topology information available and helps network administrators detect and correct network malfunctions and inconsistencies in configuration.

Media Endpoint Discovery (MED) is an LLDP enhancement that was formalized by the Telecommunications Industry Association (TIA) for voice over IP (VoIP) applications.

The Cisco implementation of LLDP is based on the IEEE 802.1ab standard. This document describes LLDP and LLDP-MED and how they are supported in Cisco software.

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 Using Link Layer Discovery Protocol in Multivendor Networks

  • Type-Length-Value (TLV) types 0 through 127
  • To support LLDP-MED, the following organizationally specific TLVs must be implemented:
    • Extended Power-via-Media Dependent Interface (MDI)
    • Inventory
    • LLDP-MED Capabilities
    • MAC/PHY Configuration Status
    • Network Policy
    • Port VLAN ID

Restrictions for Using Link Layer Discovery Protocol in Multivendor Networks

  • Use of LLDP is limited to 802.1 media types such as Ethernet, Token Ring, and Fiber Distributed Data Interface (FDDI) networks.
  • The maximum number of neighbor entries per chassis is limited on MED-capable network connectivity devices.

Information About Using Link Layer Discovery Protocol in Multivendor Networks

IEEE 802.1ab LLDP

IEEE 802.1ab Link Layer Discovery Protocol (LLDP) is an optional link layer protocol for network topology discovery in multivendor networks. Discovery information includes device identifiers, port identifiers, versions, and other details. As a protocol that aids network management, LLDP provides accurate network mapping, inventory data, and network troubleshooting information.

LLDP is unidirectional, operating only in an advertising mode. LLDP does not solicit information or monitor state changes between LLDP nodes. LLDP periodically sends advertisements to a constrained multicast address. Devices supporting LLDP can send information about themselves while they receive and record information about their neighbors. Additionally, devices can choose to turn off the send or receive functions independently. Advertisements are sent out and received on every active and enabled interface, allowing any device in a network to learn about all devices to which it is connected. Applications that use this information include network topology discovery, inventory management, emergency services, VLAN assignment, and inline power supply.


Note


LLDP and Cisco Discovery Protocol can operate on the same interface.


The figure below shows a high-level view of LLDP operating in a network node.

When you configure LLDP or Cisco Discovery Protocol location information on a per-port basis, remote devices can send Cisco medianet location information to the switch. For more information, see the Using Cisco Discovery Protocol module.

LLDP-MED

LLDP-MED operates between several classes of network equipment such as IP phones, conference bridges, and network connectivity devices such as routers and switches. By default, a network connectivity device sends out only LLDP packets until it receives LLDP-MED packets from an endpoint device. The network device then sends out LLDP-MED packets until the remote device to which it is connected ceases to be LLDP-MED capable.

Classes of Endpoints

LLDP-MED network connectivity devices provide IEEE 802 network access to LLDP-MED endpoints. LLDP-MED supports the following three classes of endpoints:

  • Generic (class 1)—Basic participant endpoints; for example, IP communications controllers.
  • Media (class 2)—Endpoints that support media streams; for example, media gateways and conference bridges.
  • Communication Device (class 3)—Endpoints that support IP communications end users; for example, IP phones and Softphone.

The figure below shows an LLDP-MED-enabled LAN.

Types of Discovery Supported

LLDP-MED provides support to discover the following types of information, which are crucial to efficient operation and management of endpoint devices and the network devices supporting them:

  • Capabilities —Endpoints determine the types of capabilities that a connected device supports and which ones are enabled.
  • Inventory —LLDP-MED support exchange of hardware, software, and firmware versions, among other inventory details.
  • LAN speed and duplex —Devices discover mismatches in speed and duplex settings.
  • Location identification —An endpoint, particularly a telephone, learns its location from a network device. This location information may be used for location-based applications on the telephone and is important when emergency calls are placed.
  • Network policy —Network connectivity devices notify telephones about the VLANs they should use.
  • Power —Network connectivity devices and endpoints exchange power information. LLDP-MED provides information about how much power a device needs and how a device is powered. LLDP-MED also determines the priority of the device for receiving power.

Benefits of LLDP-MED

  • Follows an open standard
  • Supports E-911 emergency service, which is aided by location management
  • Provides fast start capability
  • Supports interoperability between multivendor devices
  • Supports inventory management (location, version, etc.)
  • Provides MIB support
  • Supports plug and play installation
  • Provides several troubleshooting (duplex, speed, network policy) mechanisms

TLV Elements

Link Layer Discovery Protocol (LLDP) and LLDP-Media Endpoint Discovery (MED) use Type-Length-Values (TLVs) to exchange information between network and endpoint devices. TLV elements are embedded in communications protocol advertisements and used for encoding optional information. The size of the type and length fields is fixed at 2 bytes. The size of the value field is variable. The type is a numeric code that indicates the type of field that this part of the message represents, and the length is the size of the value field, in bytes. The value field contains the data for this part of the message.

LLDP-MED supports the following TLVs:

  • LLDP-MED capabilities TLV—Allows LLDP-MED endpoints to determine the capabilities that the connected device supports and has enabled.
  • Network policy TLV—Allows both network connectivity devices and endpoints to advertise VLAN configurations and associated Layer 2 and Layer 3 attributes for the specific application on that port. For example, the switch can notify a phone of the VLAN number that it should use. The phone can connect to any switch, obtain its VLAN number, and then start communicating with the call control.

By defining a network-policy profile TLV, you can create a profile for voice and voice signalling by specifying the values for VLAN, class of service (CoS), differentiated services code point (DSCP), and tagging mode. These profile attributes are then maintained centrally on the switch and propagated to the phone.

  • Power management TLV—Enables advanced power management between LLDP-MED endpoint and network connectivity devices. Allows switches and phones to convey power information, such as how the device is powered, power priority, and how much power the device needs. Supports advertisement of fractional wattage power requirements, endpoint power priority, and endpoint and network connectivity-device power status but does not provide for power negotiation between the endpoint and the network connectivity devices. When LLDP is enabled and power is applied to a port, the power TLV determines the actual power requirement of the endpoint device so that the system power budget can be adjusted accordingly. The switch processes the requests and either grants or denies power based on the current power budget. If the request is granted, the switch updates the power budget. If the request is denied, the switch turns off power to the port, generates a syslog message, and updates the power budget. If LLDP-MED is disabled or if the endpoint does not support the LLDP-MED power TLV, the initial allocation value is used throughout the duration of the connection.

Note


A system power budget is the default power allocated to a device based on its device class. However, the total power that can be sourced from a switch is finite, and there will be some power budgeting done by the power module based on the number of ports already being served, total power that can be served, and how much new ports are requesting.


  • Inventory management TLV—Allows an endpoint to send detailed inventory information about itself to the switch, including information hardware revision, firmware version, software version, serial number, manufacturer name, model name, and asset ID TLV.
  • Location TLV—Provides location information from the switch to the endpoint device. The location TLV can send this information:
    • Civic location information—Provides the civic address information and postal information. Examples of civic location information are street address, road name, and postal community name information.
    • ELIN location information—Provides the location information of a caller. The location is determined by the Emergency location identifier number (ELIN), which is a phone number that routes an emergency call to the local public safety answering point (PSAP) and which the PSAP can use to call back the emergency caller.

Benefits of LLDP

  • Follows IEEE 802.1ab standard.
  • Enables interoperability among multivendor devices.
  • Facilitates troubleshooting of enterprise networks and uses standard network management tools.
  • Provides extension for applications such as VoIP.

How to Configure Link Layer Discovery Protocol in Multivendor Networks

Enabling and Disabling LLDP Globally

LLDP is disabled globally by default. This section describes the tasks for enabling and disabling LLDP globally.

Enabling LLDP Globally

Perform this task to enable LLDP globally.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    lldp run

    4.    end


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 lldp run


    Example:
    Device(config)# lldp run
     

    Enables LLDP globally.

     
    Step 4 end


    Example:
    Device(config)# end
     

    Returns to privileged EXEC mode.

     

    Disabling LLDP Globally

    Perform this task to disable LLDP globally.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    no lldp run

      4.    end


    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 no lldp run


      Example:
      Device(config)# no lldp run
       

      Disables LLDP globally.

       
      Step 4 end


      Example:
      Device(config)# end
       

      Returns to privileged EXEC mode.

       

      Disabling and Enabling LLDP on a Supported Interface

      LLDP is enabled by default on all supported interfaces. This section describes the tasks for disabling and enabling LLDP on a supported interface.

      Disabling LLDP on a Supported Interface

      Perform this task to disable LLDP on a supported interface.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    interface type number

        4.    no lldp {med-tlv-select tlv | receive | transmit}

        5.    end


      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 ethernet 0/1
         

        Specifies the interface type and number and enters interface configuration mode.

         
        Step 4 no lldp {med-tlv-select tlv | receive | transmit}


        Example:
        Device(config-if)# no lldp receive
         

        Disables an LLDP-MED TLV or LLDP packet reception on a supported interface.

         
        Step 5 end


        Example:
        Device(config-if)# end
         

        Returns to privileged EXEC mode.

         

        Enabling LLDP on a Supported Interface

        LLDP information can be transmitted and received only on an interface where LLDP is configured and enabled. Perform this task to enable LLDP.

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    interface type number

          4.    lldp {med-tlv-select tlv | receive | transmit}

          5.    end


        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 ethernet 0/1
           

          Specifies the interface type and number and enters interface configuration mode.

           
          Step 4 lldp {med-tlv-select tlv | receive | transmit}


          Example:
          Device(config-if)# lldp transmit
           

          Enables an LLDP-MED TLV or LLDP packet transmission on a supported interface.

           
          Step 5 end


          Example:
          Device(config-if)# end
           

          Returns to privileged EXEC mode.

           

          Setting LLDP Packet Hold Time

          Hold time is the duration that a receiving device should maintain LLDP neighbor information before aging it. Perform this task to define a hold time for an LLDP-enabled device.

          SUMMARY STEPS

            1.    enable

            2.    configure terminal

            3.    lldp holdtime seconds

            4.    end


          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 lldp holdtime seconds


            Example:
            Device(config)# lldp holdtime 100
             

            Specifies the hold time.

             
            Step 4 end


            Example:
            Device(config)# end
             

            Returns to privileged EXEC mode.

             

            Setting LLDP Packet Frequency

            Perform this task to specify an interval at which the Cisco software sends LLDP updates to neighboring devices.

            SUMMARY STEPS

              1.    enable

              2.    configure terminal

              3.    lldp timer rate

              4.    end


            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 lldp timer rate


              Example:
              Device(config)# lldp timer 75
               

              Specifies the rate at which LLDP packets are sent every second.

               
              Step 4 end


              Example:
              Device(config)# end
               

              Returns to privileged EXEC mode.

               

              Monitoring and Maintaining LLDP in Multivendor Networks

              Perform this task to monitor and maintain LLDP in multivendor networks. This task is optional, and Steps 2 and 3 can be performed in any sequence.

              SUMMARY STEPS

                1.    enable

                2.    show lldp [entry {* | word} | errors | interface [ethernet number]| neighbors [ethernet number| detail]| traffic]

                3.    clear lldp {counters | table}

                4.    end


              DETAILED STEPS
                  Command or Action Purpose
                Step 1 enable


                Example:
                Device> enable
                 

                Enables privileged EXEC mode.

                • Enter your password if prompted.
                 
                Step 2 show lldp [entry {* | word} | errors | interface [ethernet number]| neighbors [ethernet number| detail]| traffic]


                Example:
                Device# show lldp entry *
                 

                Displays summarized and detailed LLDP information.

                Note   

                When the show lldp neighbors command is issued, if the device ID has more than 20 characters, the ID is truncated to 20 characters in command output because of display constraints.

                 
                Step 3 clear lldp {counters | table}


                Example:
                Device# clear lldp counters
                 

                Resets LLDP traffic counters and tables to zero.

                 
                Step 4 end


                Example:
                Device# end
                 

                Returns to user EXEC mode.

                 

                Enabling and Disabling LLDP TLVs

                LLDP TLV support is enabled by default if LLDP is enabled globally and locally on a supported interface. Specific TLVs, however, can be enabled and suppressed.

                Enabling LLDP TLVs

                Perform this task to enable an LLDP TLV on a supported interface.

                SUMMARY STEPS

                  1.    enable

                  2.    configure terminal

                  3.    interface type number

                  4.    lldp tlv-select tlv

                  5.    end


                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 ethernet 0/1
                   

                  Specifies the interface type and number on which to enable LLDP-MED and enters interface configuration mode.

                   
                  Step 4 lldp tlv-select tlv


                  Example:
                  Device(config-if)# lldp tlv-select system-description
                   

                  Enables a specific LLDP TLV on a supported interface.

                   
                  Step 5 end


                  Example:
                  Device(config-if)# end
                   

                  Returns to privileged EXEC mode.

                   

                  Disabling LLDP TLVs

                  Perform this task to disable an LLDP TLV on a supported interface.

                  SUMMARY STEPS

                    1.    enable

                    2.    configure terminal

                    3.    interface type number

                    4.    no lldp tlv-select tlv

                    5.    end


                  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 ethernet 0/1
                     

                    Specifies the interface type and number on which to disable LLDP-MED and enters interface configuration mode.

                     
                    Step 4 no lldp tlv-select tlv


                    Example:
                    Device(config-if)# no lldp tlv-select system-description
                     

                    Disables a specific LLDP TLV on a supported interface.

                     
                    Step 5 end


                    Example:
                    Device(config-if)# end
                     

                    Returns to privileged EXEC mode.

                     

                    Enabling and Disabling LLDP-MED TLVs

                    LLDP-MED TLV support is enabled by default if LLDP is enabled globally and locally on a supported interface. Specific TLVs, however, can be enabled and suppressed.

                    Enabling LLDP-MED TLVs

                    Perform this task to enable a specific LLDP-MED TLV on a supported interface.

                    SUMMARY STEPS

                      1.    enable

                      2.    configure terminal

                      3.    interface type number

                      4.    lldp med-tlv-select tlv

                      5.    end


                    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 ethernet 0/1
                       

                      Specifies the interface type and number on which to enable LLDP-MED and enters interface configuration mode.

                       
                      Step 4 lldp med-tlv-select tlv


                      Example:
                      Device(config-if)# lldp med-tlv-select inventory-management
                       

                      Enables a specific LLDP-MED TLV on a supported interface.

                       
                      Step 5 end


                      Example:
                      Device(config-if)# end
                       

                      Returns to privileged EXEC mode.

                       

                      Disabling LLDP-MED TLVs

                      Perform this task to disable a specific LLDP-MED TLV from a supported interface.

                      SUMMARY STEPS

                        1.    enable

                        2.    configure terminal

                        3.    interface type number

                        4.    no lldp med-tlv-select tlv

                        5.    end


                      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 ethernet 0/1
                         

                        Specifies the interface type and number on which to disable LLDP-MED and enters interface configuration mode.

                         
                        Step 4 no lldp med-tlv-select tlv


                        Example:
                        Device(config-if)# no lldp med-tlv-select inventory-management
                         

                        Disables a specific LLDP-MED TLV from a supported interface.

                         
                        Step 5 end


                        Example:
                        Device(config-if)# end
                         

                        Returns to privileged EXEC mode.

                         

                        Configuration Examples for Link Layer Discovery Protocol in Multivendor Networks

                        Example Configuring LLDP on Two Devices

                        The following example shows how to configure LLDP timer, hold time, and TLVs on two devices in a network. In each case we assume that the Ethernet interfaces being configured are in the UP state.

                        ! Configure LLDP on Device 1 with hold time, timer, and TLV options.
                        
                        Device1> enable
                        Device1# configure terminal
                        Device1(config)# lldp run
                        Device1(config)# lldp holdtime 150
                        Device1(config)# lldp timer 15
                        Device1(config)# lldp tlv-select port-vlan
                        Device1(config)# lldp tlv-select mac-phy-cfg
                        Device1(config)# interface ethernet 0/0
                        Device1(config-if)# end
                        00:08:32: %SYS-5-CONFIG_I: Configured from console by console
                        ! Show the updated running configuration. LLDP is enabled with hold time, timer, and TLV options configured.
                        
                        Device1# show running-config
                        
                        Building configuration...
                        Current configuration : 1397 bytes
                        !
                        version 12.2
                        service timestamps debug uptime
                        service timestamps log uptime
                        no service password-encryption
                        !
                        hostname Device1
                        !
                        boot-start-marker
                        boot-end-marker
                        !
                        !
                        no aaa new-model
                        clock timezone PST -8
                        ip subnet-zero
                        !
                        !
                        lldp timer 15
                        lldp holdtime 150
                        !
                        
                        
                        ! Configure LLDP on Device 2 with hold time, timer, and TLV options.
                        
                        Device2> enable
                        Device2# configure terminal
                        Enter configuration commands, one per line.  End with CNTL/Z.
                        Device2(config)# lldp run
                        Device2(config)# lldp holdtime 150
                        Device2(config)# lldp timer 15
                        Device2(config)# lldp tlv-select port-vlan
                        Device2(config)# lldp tlv-select mac-phy-cfg
                        Device2(config)# interface ethernet 0/0
                        Device2(config-if)# end
                        00:08:32: %SYS-5-CONFIG_I: Configured from console by console
                        
                        ! Show the updated running configuration on Device 2. LLDP is enabled with hold time, timer, and TLV options configured.
                        
                        Device2# show running-config
                        Building configuration...
                        Current configuration : 1412 bytes
                        !
                        version 12.2
                        service timestamps debug uptime
                        service timestamps log uptime
                        no service password-encryption
                        !
                        hostname R2
                        !
                        boot-start-marker
                        boot-end-marker
                        !
                        !
                        no aaa new-model
                        clock timezone PST -8
                        ip subnet-zero
                        !
                        !
                        lldp timer 15
                        lldp holdtime 150
                        !
                                 
                        
                        ! After both devices are configured for LLDP, issue the show
                         command from each device to view traffic and device information.
                        
                        Device1# show lldp traffic
                        LLDP traffic statistics:
                            Total frames out: 20
                            Total entries aged: 0
                            Total frames in: 15
                            Total frames received in error: 0
                            Total frames discarded: 0
                            Total TLVs unrecognized: 0
                        Device1# show lldp neighbors
                        Capability codes:
                            (R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
                            (W) WLAN Access Point, (P) Repeater, (S) Station, (O) Other
                        Device ID           Local Intf     Hold-time  Capability      Port ID
                        Device2             Et0/0          150        R               Et0/0
                        Total entries displayed: 1
                        Device2# show lldp traffic
                        LLDP traffic statistics:
                            Total frames out: 15
                            Total entries aged: 0
                            Total frames in: 17
                            Total frames received in error: 0
                            Total frames discarded: 2
                            Total TLVs unrecognized: 0
                        Device2# show lldp neighbors
                        Capability codes:
                            (R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
                            (W) WLAN Access Point, (P) Repeater, (S) Station, (O) Other
                        Device ID           Local Intf     Hold-time  Capability      Port ID
                        Device1             Et0/0          150        R               Et0/0
                        Total entries displayed: 1
                        

                        Additional References for Using Link Layer Discovery Protocol in Multivendor Networks

                        Related Documents

                        Related Topic

                        Document Title

                        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

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

                        Cisco IOS Carrier Ethernet Command Reference

                        LLDP

                        Link Layer Discovery Protocol

                        Per Port Location configurations

                        Per Port Location Configuration

                        Comparison of LLDP Media Endpoint Discovery (MED) and Cisco Discovery Protocol

                        LLDP-MED and Cisco Discovery Protocol

                        Standards and RFCs

                        Standards/RFCs

                        Title

                        IEEE 802.1ab

                        Station and Media Access Control Connectivity Discovery

                        RFC 2922

                        Physical Topology MIB

                        MIBs

                        MIB

                        MIBs Link

                        PTOPO MIB

                        To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

                        http:/​/​www.cisco.com/​go/​mibs

                        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 Link Layer Discovery Protocol in Multivendor Networks

                        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 Link Layer Discovery Protocol in Multivendor Networks

                        Feature Name

                        Releases

                        Feature Information

                        IEEE 802.1ab LLDP (Link Layer Discovery Protocol)

                        Cisco IOS XE Release 3.8S

                        Cisco IOS XE Release 3.9S

                        LLDP, standardized by the IEEE as part of 802.1ab, enables standardized discovery of nodes, which in turn facilitates future applications of standard management tools such as SNMP in multivendor networks.

                        In Cisco IOS XE Release 3.9S, support was added for the Cisco ASR 903 Router.

                        The following commands were introduced or modified: clear lldp, lldp and show lldp.

                        ANSI TIA-1057 LLDP-MED Support

                        15.2(3)T

                        12.2(33)SXH

                        MED is an LLDP enhancement that was formalized by the TIA for VoIP applications. The Cisco implementation of LLDP is based on the IEEE 802.1ab standard.

                        The following commands were introduced or modified: lldp and lldp (interface).