GIGAswitch System: A High-Performance Packet-Switching Platform

Abstract

The GIGAswitch system is a high-performance packet-switching platform built on a 36-port 100 Mb/s crossbar switching fabric. The crossbar is data link independent and is capable of making 6.25 million connections per second. Digital’s first GIGAswitch system product uses 2-port FDDI line cards to construct a 22-port IEEE 802.1d FDDI bridge. The FDDI bridge implements distributed forwarding in hardware to yield forwarding rates in excess of 200,000 packets per second per port. The GIGAswitch system is highly available and provides robust operation in the presence of overload. The GIGAswitch system is a multiport packetswitching platform that combines distributed forwarding hardware and crossbar switching to attain very high network performance. When a packet is received, the receiving line card decides where to forward the packet autonomously. The ports on a GIGAswitch system are fully interconnected with a custom-designed, very large-scale integration (VLSI) crossbar that permits up to 36 simultaneous conversations. Data flows through 100 megabits per second (Mb/s) point-to-point connections, rather than through any shared media. Movement of unicast packets through the GIGAswitch system is accomplished completely by hardware. The GIGAswitch system can be used to eliminate network hierarchy and concomitant delay. It can aggregate traffic from local area networks (LANs) and be used to construct workstation farms. The use of LAN and wide area network (WAN) line cards makes the GIGAswitch system suitable for building, campus, and metropolitan interconnects. The GIGAswitch system provides robustness and availability features useful in high-availability applications like financial networks and enterprise backbones. In this paper, we present an overview of the switch architecture and discuss the principles influencing its design. We then describe the implementation of an FDDI bridge on the GIGAswitch syste