Configuring Link Layer Discovery Protocol

The NetScaler appliance supports the industry standard (EEE 802.1AB) Link Layer Discovery Protocol (LLDP). LLDP is a layer 2 protocol that enables the NetScaler appliance to advertise its identity and capabilities to the directly connected devices, and also learn the identity and capabilities of these neighbour devices. Using LLDP, the NetScaler appliance transmits and receives information in the form of LLDP messages known as LLDP packet data units (LLDPUs).

An LLDPU is a sequence of type, length, value (TLV) information elements. Each TLV holds a specific type of information about the device that transmits the LLDPDU. The NetScaler appliance sends the following TLVs in each LLDPU:

  • Chassis ID
  • Port ID
  • Time-to-live value
  • System name
  • System description
  • Port description
  • System capabilities
  • Management address
  • Port VLAN ID
  • Link aggregation

Note: You cannot specify the TLVs to be sent in LLDP messages.

NetScaler interfaces support the following LLDP modes:

  • NONE. The interface neither receives from nor transmits LLDP messages to the directly connected device.
  • TRANSMITTER. The interface transmits LLDP messages to the directly connected device but does not receive LLPD messages from the directly connected device.
  • RECEIVER. The interface receives LLDP messages from the directly connected device but does transmit LLPD messages to the directly connected device.
  • TRANSCEIVER. The interface transmits LLDP messages to and receives LLDP messages from the directly connected device.

The LLDP mode of an interface depends on the LLDP mode configured at the global and the interface levels. The following table shows the modes resulting from the available combinations of global- and interface-level settings: Interface and global level LLDP modes.

Note the following points related to LLDP messages transmitted or received by the NetScaler:

  • Transmitting LLDP messages. The NetScaler appliance transmits LLDPUs from interfaces that are operating in either TRANSMITTER or TRANSCEIVER LLDP mode.

    Following are the global LLDP transmitting parameters on the NetScaler appliance:

    • Timer. Interval, in seconds, between LLDPUs that the NetScaler appliance sends to a directly connected device.
    • Holdtime Multiplier. A multiplier for calculating the duration for which the receiving device stores the LLDP information in its database before discarding or removing it. The duration is calculated as the Holdtime Multiplier parameter value multiplied by the Timer parameter value.
  • Receiving LLDP Messages. The NetScaler appliance stores the LLDPDU information in its Management Information base (MIB). The stored LLDP information is classified or grouped under the ID of the interface that received the LLDPDU. The NetScaler appliance retains this LLDP information for the duration specified in the received LLDPU.

    If the appliance receives another LLDPDU on an interface before the stored LLDP information for that interface is discarded, the appliance replaces the stored LLDP information for that interface with information in the new LLDPDU.

Configuration Steps

Configuring LLDP on a NetScaler appliance consists of the following tasks:

  1. Set global level LLDP parameters. In this task, you set the global LLDP parameters such as LLDP Timer, Hold Time Multiplier, and LLDP mode.

  2. Set the interface level LLDP parameters. In this task, you set the LLDP mode for an interface.

  3. (Optional) Display neighbor-device information. You can display the neighbor-device LLDP information collected on all of the NetScaler appliance’s interfaces, or just the LLDP information collected on specified interfaces. If you do not specify an interface, the information is shown for all interfaces.

Following are the prerequisites for configuring LLDP on a NetScaler appliance:

  1. Make sure that you understand the standard LLDP protocol (IEEE 802.1AB).

  2. Verify that you have configured LLDP on the desired directly connected devices.

NetScaler command line procedures

To set global level LLDP parameters by using the NetScaler command line:

At the command prompt, type:

  • set lldp param [-[-holdtimeTxMult <positive_integer>][-timer <positive_integer>] [-Mode <Mode>]
  • show lldp param

To configure an interface for LLDP by using the NetScaler command line:

At the command prompt, type:

  • set interface <id> -lldpmode <lldpmode>
  • show interface <id>

To display neighbor device information by using the NetScaler command line:

At the command prompt, type one of the following commands:

  • show lldp neighbors
  • show lldp neighbors <ifnum>

NetScaler GUI procedures

To set the global level LLDP parameters by using the NetScaler GUI:

  1. Navigate to System > Network, and click Configure LLDP Parameters.
  2. Set the following parameters:

    • Hold Timer Multiplier
    • Timer
    • Mode

To configure an interface for LLDP by using the NetScaler GUI:

Navigate to System > Network > Interfaces, open the interface, and set the LLDP mode parameter.

To display neighbor device information by using the NetScaler GUI:

Navigate to System > Network > Interfaces and, in the Action list, select View LLDP Neighbors.

LLDP Support in a Cluster Setup

In a cluster setup, the NetScaler GUI and NetScaler CLI display the LLDP neighbour configuration of all or specific cluster nodes when the GUI or CLI is accessed through the Cluster IP address (CLIP). Any change made to the global level LLDP mode is applied to the global level LLDP mode on each of the cluster nodes.

Consider an example of a cluster setup of three nodes, NS1, NS2, and NS3. Each of these nodes are connected to both routers Router-1 and Router-2. The following output is displayed when the show lldp neighbor -summary operation is performed on the Cluster CLI that is accessed through the Cluster IP address (CLIP) of the cluster setup. The output shows the LLDP neighbour information of all these nodes.

> show lldp neighbor -summary

Node Id: 1
------------------------------------------------------------
    Interface    ChassisId           PortId     System name
------------------------------------------------------------
1     1/1/1      fe:c7:3b:13:bd:11    1/1         Router-1

2     1/1/2      12:68:7b:9e:4c:11    1/1         Router-2

Node Id: 2
-------------------------------------------------------------
    Interface    ChassisId           PortId     System name
-------------------------------------------------------------
1     2/1/1      fe:c7:3b:13:bd:12    1/2        Router-1

2     2/1/2      12:68:7b:9e:4c:12    1/2        Router-2

Node Id: 3
-------------------------------------------------------------
    Interface    ChassisId            PortId     System name
-------------------------------------------------------------

1     3/1/1       fe:c7:3b:13:bd:13    1/3        Router-1

2     3/1/2       12:68:7b:9e:4c:13    1/3        Router-2

Done

Configuring Link Layer Discovery Protocol