How to Configure Link Redundancy Using a Failover Interface Set (FIS) on NetScaler

This article describes how to configure the NetScaler appliances in a High Availability setup with redundant Switches to protect against Switch outages.

Note: This article assumes familiarity with configuring NetScaler appliances in an High Availability setup and configuring port virtual LANs (VLANs) on a Switch.

Background

To overcome a Switch being the single point of failure in the network, the appliances of a High Availability setup can be configured to be physically connected to redundant Switches. This addresses the following scenario:

• NetScaler appliance A is connected to Switch A

• NetScaler appliance B is connected to Switch B

• NetScaler appliances A and B are part of a High Availability setup

If both Switch A and NetScaler appliance B fail, no network traffic can reach the local virtual servers. To overcome this failure scenario, two links can be used from each NetScaler appliance with each link connected to a different Switch.

Using link redundancy, you can group the two interfaces into a Failover Interface Set, and therefore prevent the failure of a single link from causing a failover to the secondary appliance unless all interfaces on the primary appliance stop functioning.

Use any of the following methods to configure the NetScaler appliances in a High Availability setup with redundant Switches.
Note: In case both interfaces on a NetScaler appliance are connected to the same VLAN, Failover Interface Set does not prevent loops.

Using the NetScaler Command Line Interface (CLI)

To configure the NetScaler appliances in a High Availability setup with redundant Switches, complete the following procedure from the command line interface of the appliance:

1. Run the following command to disable L2 mode on both the appliances:
   >disable ns mode L2

2. Create two separate port VLANs on the switches; for example, VLAN 2 and VLAN 3.

3. Enable interfaces 1/1 and 1/2.

4. Connect 1/1 from both appliances to VLAN 2.

5. Connect 1/2 from both appliances to VLAN 3.

6. Run the following commands to set up a Failover Interface Set group:
   >add fis <set name>
   >bind fis <set name> 1/1
   >bind fis <set name> 1/2

Using the Graphical User Interface (GUI)

To configure the NetScaler appliances in a High Availability setup with redundant Switches, complete the following procedure from the Configuration Utility of the appliance:

1. Expand the System node and select Settings node.

2. Click the Configure Modes link in the Modes and Features section.

3. Clear the Layer 2 Mode option.

4. Select the High Availability node.

5. Select the Failover Interface Set tab and then click Add.

6. Configure the Failover Interface Set name and move the appropriate interfaces from the Available Interfaces list to the Configured Interfaces list, as shown in the following screen shot:

   

7. Click Create.

Citrix Documentation - Configuring Link Redundancy

Redundant Interface Set

A redundant interface set is a set of interfaces where one of the interfaces is active and the remaining ones are standby. If the active interface fails, one of the standby interfaces takes over and becomes active. For more information on Redundant interface set, refer to Citrix Documentation.