TX Matrix Routing Matrix Switch Fabric Architecture

The routing matrix switch fabric consists of five data switching planes. The switch fabric uses ASICs to perform high-speed packet forwarding between the T640 routers. Each TX-SIB and the T640-SIBs connected to it represent a data switching plane that spans the TX Matrix router and all T640 routers in the routing matrix. The switching planes are connected by high-speed optical links within fiber-optic array cables.

Consider a packet that enters a T640 router and is destined for another T640 router in the routing matrix. When the packet enters an interface on a PIC in a T640 router, it is forwarded to the switch fabric by a Packet Forwarding Engine on that router (see T640 Core Router Hardware Guide  for more details). The packet is forwarded through the switch fabric from the source T640 router, through the TX Matrix router, to the target T640 router. The switch fabric allows high-priority traffic from any Packet Forwarding Engine to an egress Packet Forwarding Engine to be given preferential treatment over low-priority traffic from any other Packet Forwarding Engine. The Packet Forwarding Engine on the target T640 router forwards the packet to the destination PIC and interface.

The switch fabric can forward up to 3 Gpps. The maximum aggregate throughput rate for the TX Matrix router is 2.56 Tbps (full duplex). Figure 1 illustrates the switch fabric architecture.

Figure 1: Routing Matrix Switch Fabric Architecture