logical interface (LIF)

A logical interface (LIF) Is a software entity consisting of an IP address that is associated with a number of attributes such as a role, a home port, a firewall policy, a home node, a routing group and a list of ports for failover purposes.

Logical interfaces are created through configuration. Each LIF may be associated with a specific physical interface or device.

LIFs fill a number of purposes in cluster computing and have different roles to this end. The type of LIF role determines the traffic type it passes over its interface. Roles also determine the failover  and firewall rules, security, load balancing, how they route traffic and how they are used by cluster administrators.

LIF roles:
 

• Data LIFs use a Vserver and communicate with clients, configured through data specific ports.
• Cluster LIFs  are used for intra-cluster traffic, configured through specific cluster ports. They generally use 10-GbE ports and can be used for failover for cluster ports on the same node.
• Intercluster LIFs are used for cross-cluster communication, replication and backup. They are configured via data ports or inter-cluster ports. Intercluster LIFs are needed for each node to establish a peering relationship.
• Cluster management LIFs are used for overall cluster management. They can be configured on data ports or node-management ports and can fail over to any node management LIF or data port in the cluster.
• Node managment LIFs  provide a dedicated IP for management of specific nodes. They are created at the time of cluster joining or creation and configured over node-managment or data ports. They can fail over to other data or node-managment ports on the same node.