VSX clustering is a feature that allows two Aruba CX switches to operate as a single logical device, providing high availability, scalability, and simplified management. VSX clustering has several benefits over spanning tree configuration, such as:

Dual control plane provides better resiliency. Unlike stacking, where switches share a single control plane, VSX switches have independent control planes that synchronize their states over an inter-switch link (ISL). This means that if one switch fails or reboots, the other switch can continue to operate without affecting traffic flows or network services.

Active-active forwarding provides better performance. Unlike spanning tree, where some links are blocked to prevent loops, VSX switches use all available links for forwarding traffic, providing load balancing and increased bandwidth utilization.

Multichassis LAG provides better redundancy. Unlike single-chassis LAG, where all member ports belong to one switch, VSX switches can form multichassis LAGs with downstream or upstream devices, where member ports are distributed across both switches. This provides link redundancy and seamless failover in case of switch or port failure.