A Citrix Administrator needs to configure a Citrix ADC high availability (HA) pair with each Citrix ADC in a different subnet. What does the administrator need to do for HA to work in different subnets?

Independent Network Configuration (INC) mode is a specific high availability (HA) configuration for Citrix ADC appliances that are deployed in different subnets or networks. In a standard HA setup, both nodes are in the same subnet and share network configurations. However, when nodes are in different subnets, they require unique network configurations (such as Subnet IPs (SNIPs) and static routes). INC mode allows each node to have its own independent network settings, which are not synchronized between the pair, while still synchronizing application-specific configurations like virtual servers. This is the required configuration to make HA functional across different subnets.

A. Configure SyncVlan: SyncVlan is used to designate a specific VLAN for HA synchronization traffic. While necessary for HA communication, it does not enable the core functionality required for nodes in different subnets.
B. Turn on fail-safe mode: Fail-safe mode is a feature that prevents a split-brain scenario by forcing a failover if the primary node loses connectivity to critical network resources. It enhances HA reliability but does not enable it across subnets.
C. Turn on HA monitoring on all interfaces: HA monitoring (HAMON) is used to monitor the health of interfaces on the ADC. A failure on a monitored interface can trigger an HA failover, but this feature does not facilitate the setup of an HA pair across different networks.

1. Citrix ADC 13.1 Product Documentation:

Title: High availability nodes in different networks

Reference: In the section "High availability nodes in different networks

" the documentation states

"In a high availability setup

you can configure the two nodes in different networks. This type of configuration is called an Independent Network Configuration (INC). In an INC

the subnet IP (SNIP) addresses and VLANs of one node are different from the other node." This directly supports the use of INC mode for the described scenario.

Source: Citrix Product Documentation

"High availability

" "High availability deployment modes

" "High availability nodes in different networks."

2. Citrix ADC 13.1 Product Documentation:

Title: Configuring an Independent Network High Availability Setup

Reference: The "To configure an independent network HA setup by using the command line interface" section provides the command to enable this mode: add ha node -inc ENABLED. This confirms that INC is a specific mode that must be enabled.

Source: Citrix Product Documentation

"High availability

" "Configuring high availability

" "Configuring an Independent Network High Availability Setup."