# LLDP

### 1. Function Overview

LLDP is a protocol for passing device management information between a device and its neighboring devices.
This is a simple protocol in which a device unidirectionally advertises its own information and neighbor devices receive this information. However, since LLDP-compliant devices maintain the information received from neighbor devices as MIB objects, the user can access this information via SNMP and ascertain what type of devices are connected to which interfaces are.
This protocol is also used for negotiation between devices that support PoE (Power Over Ethernet).

### 2. Definition of Terms Used

LLDP

Link Layer Discovery Protocol.
This is defined in IEEE 802.1AB.

LLDP-MED

LLDP for Media Endpont Devices.
This is defined in ANSI/TIA-1057.

### 3. Function Details

#### 3.1. Operating specifications

##### 3.1.1. Basic specifications

This product supports the following operations.

- LLDP frames are transmitted from any LAN/SFP port to convey information about the device itself.

- LLDP frames are received at any LAN/SFP port to obtain information about neighboring devices.

- Information transmitted via LLDP about the device itself, and information obtained via LLDP about neighbor devices, etc., can be referenced via SNMP.

LLDP sends and receives information using Type, Length, and Value (TLV) attributes.
For details on the TLV information sent by this product, refer to TLV list.

This product’s LLDP supports the following MIBs of SNMP. For details, refer to 3.3 Supported MIBs.

- LLDP-MIB

- LLDP-EXT-DOT3-MIB

- LLDP-V2-MIB

- LLDP-EXT-DOT3-V2-MIB

- LLDP-EXT-MED-MIB

The following settings are required in order to use the LLDP function.

- Enable LLDP functionality for the overall system using the lldp run command.

- Create LLDP agents at applicable interfaces using the lldp-agent command.

- Specify the LLDP frame transmit/receive mode using the set lldp command.

The LLDP function is enabled in default settings for this product.

LLDP frames are always transmitted without tags, regardless of the VLAN settings of the transmitting switch port.
They are also transmitted without tags from a trunk port without a native VLAN.

When LLDP is used for PoE negotiation, it is necessary to configure the port to which the PoE powered device is connected so that LLDP can be transmitted and received.

##### 3.1.2. Transmitted information settings

Use the following commands to specify the LLDP frames that are transmitted from the device itself. There are also some TLVs (required TLVs) that are transmitted regardless of the settings of the following commands.

- tlv-select basic-mgmt command (basic management TLV)

- tlv-select ieee-8021-org-specific command (IEEE 802.1 TLV)

- tlv-select ieee-8023-org-specific command (IEEE 802.3 TLV)

- tlv-select med command (LLDP-MED TLV)

The system name and description that are transmitted in the basic management TLVs are specified by the lldp system-name command and the lldp system-description command.
The type of management address is set management-address-tlv command.

##### 3.1.3. Transmission timer setting

LLDP frame transmission interval is specified by the set timer msg-tx-interval command.
The multiplier for calculating the hold time (TTL) for device information is set by the set msg-tx-hold command.
The TTL for LLDP transmission is the result of the following calculation. The default is 121 seconds.

- TTL = ( value set by the “set timer msg-tx-interval” command ) × ( value set by the “set msg-tx-hold” command ) + 1 (second)

When a neighbor device is connected to a LAN/SFP port for which LLDP frame transmission is enabled, LLDP frames are transmitted rapidly at a fixed interval according to the high-speed transmission interval setting.
The transmission interval and the number of transmissions for high speed transmission are set by the set timer msg-fast-tx command and the set tx-fast-init.

If the set lldp command is used to change the setting from a state in which LLDP frame transmission is enabled to a state in which the frame transmission is disabled, this product transmits a shut-down frame, notifying the neighbor device that LLDP frame transmission has stopped.
Subsequently, even if LLDP frame transmission is once again enabled, LLDP frame transmission to the neighbor device is stopped for a time.
The stopped duration until the next transmission occurs after transmitting the shutdown frame is set by the set timer reinit-delay command.

##### 3.1.4. Maximum connected devices setting

The maximum number of connected devices that can be managed by the corresponding port is set by the set too-many-neighbors limit command.
The default value for the maximum number of connected devices is 5 devices.

##### 3.1.5. Checking LLDP information

LLDP interface settings and received information about neighbor devices can be checked by using the show lldp interface command or the show lldp neighbors command.

To clear the LLDP frame counter, use the clear lldp counters command.

##### 3.1.6. Other functions using LLDP

- Access point link
  This function sends and receives proprietary LLDP frames between Yamaha network switches and Yamaha wireless access points to automatically perform specific processes, such as specifying settings based on information in the LLDP notifications or saving log data.
  AP link function setting is specified using the lldp auto-setting command.
  For details, refer to LLDP Automatic Setting (Access Point Link).

- Dante optimization setting
  This function automatically specifies settings optimized for the Dante digital audio network.
  The Dante optimization settings function is set using the lldp auto-setting command.
  For more information, refer to Dante Optimization Settings Function.

- LLDP reception interval monitoring
  This function monitors whether specific connected terminals are live or dead.
  For details, refer to Terminal Monitoring.

- Voice VLAN
  With the voice VLAN function, LLDP-MED can be used to specify voice traffic settings for IP telephony.
  For details, refer to VLAN.

#### 3.2. TLV list

The TLVs supported by this product are listed below.

- Required TLVs

- Basic management TLVs

- IEEE 802.1 TLV

- IEEE 802.3 TLV

- LLDP-MED TLV

For detailed specifications of each TLV, refer to IEEE 802.1AB (LLDP) and ANSI/TIA-1057 (LLDP-MED).
The TLVs that are transmitted by this product are explained below.

##### 3.2.1. Required TLVs

If LLDP frame transmission is enabled, these TLVs are always transmitted.
Three TLVs are transmitted: chassis ID, port ID, and TTL.
The required TLVs are listed below.

Type | Description | Length | Value (only fixed values are listed)
--- | --- | --- | ---
Chassis ID | Chassis ID | 6 bytes | MAC address of the device
Port ID | Port ID | 7 to 8 bytes | Port name (portX.X)
Time To Live (TTL) | Hold time of device information (sec) | 2 bytes |

##### 3.2.2. Basic management TLVs

These TLVs are transmitted if LLDP frame transmission is enabled and the tlv-select basic-mgmt command is specified.
System-related management information is transmitted, such as name, system capabilities, and address.
The basic management TLVs are listed below.

Type | Description | Length | Value (only fixed values are listed)
--- | --- | --- | ---
Port Description | Port description string | 0 to 255 bytes |
System Name | System name string Default: Hostname | 0 to 255 bytes |
System Description | System description string Default: Model name + Firmware revision | 0 to 255 bytes |
System Capabilities | Capabilities supported by the system | 2 bytes | 0x0004（bridge）
Enabled system capabilities | 2 bytes | 0x0004（bridge）
Management Address | Management address IP address (4 bytes) or MAC address (6 bytes) | 4 or 6 bytes |
Interface sub-type | 1 byte | 0x02 (ifIndex)
Interface number | 4 Byte | ifIndex value

##### 3.2.3. IEEE 802.1 TLV

These TLVs are transmitted if LLDP frame transmission is enabled and the tlv-select ieee-8021-org-specific command is specified.
These transmit information such as VLAN and link aggregation for the corresponding port.
The IEEE 802.1 TLVs are listed below.

Type | Description | Length | Value (only fixed values are listed)
--- | --- | --- | ---
Port VLAN ID | Port VLAN number | 2 bytes |
Port and Protocol VLAN ID | Protocol VLAN support and enable/disable | 1 byte | 0x00 (no support)
Protocol VLAN number | 2 bytes | 0x0000
Protocol Identity | Byte string that identifies the protocol | 0 to 255 bytes |
Link Aggregation | Aggregation capability and status | 1 byte |
ifIndex number of aggregation logical interface | 4 Byte |
VLAN Name | Name of the VLAN to which the port belongs | 0 to 32 bytes |

##### 3.2.4. IEEE 802.3 TLV

These TLVs are transmitted if LLDP frame transmission is enabled and the tlv-select ieee-8023-org-specific command is specified.
Auto negotiation support information, PoE information, etc. for the corresponding port are transmitted.
The IEEE 802.3 TLVs are listed below.

Type | Description | Length | Value (only fixed values are listed)
--- | --- | --- | ---
MAC/PHY Configuration/Status | Auto negotiation support, and whether enabled or disabled | 1 byte |
Supported communication method for auto negotiation | 2 bytes |
Operational MAU Type Data signaling rate and duplex mode (IETF RFC 4836) | 2 bytes |
Power Via MDI | MDI power support status | 1 byte |
PSE power pair Selection of wiring to be used for power supply | 1 byte | 0x01 (signal line)
Power class Class0 to Class4 | 1 byte |
Power type PSE Device/PD Device | 2 bit | 0b00 (PSE Device)
Power source Primary/Secondary | 2 bit | 0b01 (Primary)
Priority | 2 bit |
Power required from PD device (in units of 0.1 watts) | 2 bytes |
Power supply of PSE device (in units of 0.1 watts) | 2 bytes |
Link Aggregation | Aggregation capability and status | 1 byte |
ifIndex number of aggregation logical interface | 4 Byte |
Maximum Frame Size | Maximum frame size | 2 bytes |

##### 3.2.5. LLDP-MED TLV

These TLVs are transmitted if LLDP frame transmission is enabled and the tlv-select med command is specified.
These are used to transmit information about network policy and extended PoE of the port.
The LLDP-MED TLVs are listed below.

Type | Description | Length | Value (only fixed values are listed)
--- | --- | --- | ---
LLDP-MED Capabilities | Transmittable LLDP-MED TLVs | 2 bytes | 0x000B (LLDP-MED Capabilities, Network Policy, Extended Power-via-MDI TLV )
Device type | 1 byte | 0x04 (Network Connectivity)
Network Policy | Application type | 1 byte | 0x01 (Voice)
Voice VLAN information | 3 Byte |
Extended Power-via-MDI | Power type PSE Device/PD Device | 2 bit | 0b00 (PSE Device)
Power source Primary/Secondary | 2 bit | 0b01 (Primary)
Power priority | 4 bit |
Power required from PD (in units of 0.1 watts) | 2 bytes |

Network policy is only transmitted via the port specified by Voice VLAN.

#### 3.3. Supported MIBs

Refer to the following SNMP MIB Reference for information on the MIBs that are supported.

- SNMP MIB Reference

### 4. Related Commands

Related commands are indicated below.
For details on the commands, refer to the Command Reference.

Operations | Operating commands
--- | ---
Enable LLDP function | lldp run
Set system description text string | lldp system-description
Set system name | lldp system-name
Create LLDP agent | lldp-agent
Set LLDP transmission/reception mode | set lldp
Set the type of management address | set management-address-tlv
Set basic management TLV | tlv-select basic-mgmt
Set IEEE-802.1 TLV | tlv-select ieee-8021-org-specific
Set IEEE-802.3 TLV | tlv-select ieee-8023-org-specific
Set LLDP-MED TLV | tlv-select med
Set the LLDP frame transmission interval | set timer msg-tx-interval
Set duration to stop transmission following LLDP transmission stop until transmission is once again possible | set timer reinit-delay
Set the multiplier for calculating the hold time (TTL) for device information | set msg-tx-hold
Set LLDP frame transmission interval for high-speed transmission term | set timer msg-fast-tx
Set number of LLDP frames transmitted for high-speed transmission term | set tx-fast-init
Set the maximum number of connected devices that can be managed by each port | set too-many-neighbors limit
Show interface status | show lldp interface
Show connected device information for all interfaces | show lldp neighbors
Clear LLDP frame counters | clear lldp counters
Set Dante optimization setting function and AP link function using LLDP | lldp auto-setting

### 5. Examples of Command Execution

#### 5.1. Set LLDP frame transmission/reception

For port1.1, enable LLDP frame transmission/reception.
Basic management TLVs, IEEE 802.1 TLVs, IEEE 802.3 TLVs, and LLDP-MED TLVs are transmitted.
Set the LLDP frame transmission interval to 60 seconds. Set the LLDP frame TTL to 181 seconds.
Set “SWITCH1” as the name of the transmitting system.
Specify 10 as the maximum number of connected devices managed by the port.

    Yamaha#configure terminal
    Yamaha(confif)#lldp system-name SWITCH1 (1)
    Yamaha(config)#interface port1.1
    Yamaha(config-if)#lldp-agent (2)
    Yamaha(lldp-agent)#tlv-select basic-mgmt (3)
    Yamaha(lldp-agent)#tlv-select ieee-8021-org-specific (4)
    Yamaha(lldp-agent)#tlv-select ieee-8023-org-specific (5)
    Yamaha(lldp-agent)#tlv-select med (6)
    Yamaha(lldp-agent)#set timer msg-tx-interval 60 (7)
    Yamaha(lldp-agent)#set msg-tx-hold 3 (8)
    Yamaha(lldp-agent)#set too-many-neighbors limit 10 (9)
    Yamaha(lldp-agent)#set lldp enable txrx (10)
    Yamaha(lldp-agent)#exit
    Yamaha(config-if)#exit
    Yamaha(config)#lldp run (11)
    Yamaha(config)#exit

1 | Set system name
2 | Create LLDP agent, mode transition
3 | Set basic management TLV
4 | Set IEEE 802.1 TLV
5 | Set IEEE 802.3 TLV
6 | Set LLDP-MED TLV
7 | Set transmission interval
8 | Set multiplier for TTL calculation: TTL = 60 x 3 + 1 = 181 seconds
9 | Maximum connected devices setting
10 | Set LLDP transmission/reception mode
11 | Enable LLDP function

#### 5.2. Show LLDP interface status

Show the port1.1 LLDP interface information.

    Yamaha#show lldp interface port1.1 (1)
    Agent Mode                    : Nearest bridge
    Enable (tx/rx)                : Y/Y
    Message fast transmit time    : 1
    Message transmission interval : 30
    Reinitialization delay        : 2
    MED Enabled                   : Y
    Device Type                   : NETWORK_CONNECTIVITY
    LLDP Agent traffic statistics
      Total frames transmitted       : 0

1 | Show interface information

#### 5.3. Show LLDP connected device information

Show LLDP connected device information.

    Yamaha#show lldp neighbors (1)
    Interface Name           : port1.1
    System Name              : SWX3100-10G
    System Description       : SWX3100 Rev.4.01.02 (Mon Dec  4 12:33:18 2017)
    Port Description         : port1.3
    System Capabilities      : L2 Switching
    Interface Numbering      : 2
    Interface Number         : 5003
    OID Number               :
    Management MAC Address   : ac44.f230.0000
    Mandatory TLVs
      CHASSIS ID TYPE
        IP ADDRESS           : 0.0.0.0
      PORT ID TYPE
        INTERFACE NAME       : port1.3
      TTL (Time To Live)     : 41
    8021 ORIGIN SPECIFIC TLVs
      Port Vlan id                : 1
      PP Vlan id                  : 0
      Remote VLANs Configured
        VLAN ID                   : 1
        VLAN Name                 : default
      Remote Protocols Advertised :
        Multiple Spanning Tree Protocol
      Remote VID Usage Digestt    : 0
      Remote Management Vlan      : 0
      Link Aggregation Status     :
      Link Aggregation Port ID    :
    8023 ORIGIN SPECIFIC TLVs
      AutoNego Support            : Supported Enabled
      AutoNego Capability         : 27649
      Operational MAU Type        : 30
      Power via MDI Capability (raw data)
        MDI power support         : 0x0
        PSE power pair            : 0x0
        Power class               : 0x0
        Type/source/priority      : 0x0
        PD requested power value  : 0x0
        PSE allocated power value : 0x0
      Link Aggregation Status     :
      Link Aggregation Port ID    :
      Max Frame Size              : 1522
    LLDP-MED TLVs
      MED Capabilities            :
        Capabilities
        Network Policy
      MED Capabilities Dev Type   : End Point Class-3
      MED Application Type        : Reserved
      MED Vlan id                 : 0
      MED Tag/Untag               : Untagged
      MED L2 Priority             : 0
      MED DSCP Val                : 0
      MED Location Data Format    : ECS ELIN
        Latitude Res      : 0
        Latitude          : 0
        Longitude Res     : 0
        Longitude         : 0
        AT                : 0
        Altitude Res      : 0
        Altitude          : 0
        Datum             : 0
        LCI length        : 0
        What              : 0
        Country Code      : 0
        CA type           : 0
      MED Inventory

1 | Show connected device information

### 6. Points of Caution

None

### 7. Related Documentation

- SNMP

- Terminal Monitoring

- Dante Optimization Settings

- PoE Control

- VLAN

- LLDP Automatic Setting (Access Point Link)

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