A single FlexStack connection between two members is a full duplex 10Gbps connecton. Each Cisco Catalyst 2960-S member supports two FlexStack connections. Each FlexStack member can simultaneously send and receive Ethernet traffic over both stack links at line rate, effectively giving 20Gbps of stack bandwidth per member.
Up to four switches can stacked together using FlexStack to form a single logical switch. Logical switch is another term used to identify a stack of switches. There are multiple physical switches acting as a single unit. This single unit behavior is a logical switch.
Cisco Catalyst 2960-S switches running FlexStack use a hop-by-hop method of transferring Ethernet packets across the stack. Packets traverse the stack by going from one member to another over the FlexStack links until the packet reaches its destination. This is the same behavior as multiple standalone Ethernet switches forwarding packets from one switch to another.