Redundant port capability is provided when Active/Active Clustering is enabled. If one port should have a fault, the traffic is seamlessly handled through the redundant port without causing an HA or Active/Active failover. A Redundant Port field in the Network > Interfaces > Edit Interface dialog becomes available when Active/Active Clustering is enabled.
When configuring a redundant port, the interface must be unused; that is, not assigned to any zone. The two ports must be physically connected to the same switch, or preferably, to redundant switches in the network.
While all Cluster Nodes are up and processing traffic normally, redundant ports remain standby and are ready for use if the partner port goes down for any reason. If one Cluster Node goes down, causing an Active/Active failover, the redundant port on the remaining Cluster Node is put to use immediately to handle the traffic for the Virtual Group that was owned by the failed node. This provides load sharing.
For example, say we have a deployment in which Virtual Group 1 is owned by Cluster Node 1 and Virtual Group 2 is owned by Cluster Node 2. The Cluster Nodes are configured with redundant ports, X3 and X4. No traffic is sent on X4 while all nodes are functioning properly. If Cluster Node 2 goes down, Virtual Group 2 is now also owned by Cluster Node 1. At this point, the redundant port X4 begins to be used for load sharing. Virtual Group 1 traffic is sent on X3, while Virtual Group 2 traffic is sent on X4. In a larger deployment, if Cluster Node 1 owns three or four Virtual Groups, traffic is distributed among the redundant ports – traffic for Virtual Groups 1 & 3 is sent on X3, while traffic for Virtual Groups 2 & 4 is sent on X4.
When a redundant switch is configured, SonicWall recommends using a redundant port to connect to it. While it is possible to connect a redundant switch without using a redundant port, this involves complex configuration using probes. A redundant switch can be deployed anywhere in the network depending on the need for high availability. For example, a redundant switch might be deployed on the WAN side if traffic passing through it is business-critical.
Deployment with Redundant Routers, Switches, and Ports shows a deployment that includes redundant routers, switches, and ports on the WAN side, but is not a Full Mesh deployment because the LAN side does not use redundancy.
Deployment with Redundant Routers, Switches, and Ports
Full Mesh is not required when deploying redundant ports or switches, but a Full Mesh deployment includes them. A Full Mesh deployment uses redundant ports on each of the main traffic ports (LAN, WAN, etc.), and uses redundant upstream routers in addition to redundant switches.
For more information about Full Mesh deployment, see About Full Mesh Deployments and the Active/Active Clustering Full Mesh Deployment Technote, available on https://support.sonicwall.com/.
