S9500 adopts the switch architecture based on Crossbar which implements non-block switch with a matrix structure. The Crossbar switch network will not have blocks due to the bandwidth bottleneck. The S9500 switch architecture is illustrated in the following picture:
PP: Packets Processor, responsible for forwarding packets and managing the cache and queue.
FA: Fabric/Stacking Adapter, used as the adapter for establishing a connection between PP and Crossbar.
Crossbar: An advanced switching technology to connect multiple PPs with FA.
The packet received by S9500 enters PP through PHY. PP analyzes the packet and decides whether to abandon, forward or send it to CPU. Forwarding includes intra-board forward and trans-board forward. For trans-board forwarding, the packet is delivered by the local FA to the peer FA through the crossbar, and forwarded by the peer PP.
S9500 establishes an independent management channel for communication between the MPU CPU and the LPU CPU.