1. Motivation CPU performance doubles about every 18 months.
PC Bus performance doubles about every 3 years.
10000
1000
Log Bandwidth
75-100
100 66
40-50
PCI-X
25-33
PCI 64/66
16-20
PCI 32/33 12
EISA
MCA
So what was the motivation behind this development? CPU performance doubles about every 18 months, while PC Bus performance doubles about every 3 years. So while the demand for bandwidth keeps increasing, bus technology falls more and more behind every day. This dilemma calls for a new technology that is capable of not only providing much higher frequencies and bandwidth, but also having the ability to evolve with increasing CPU performance over time. 10 8
16b ISA
8b ISA
4.77
1980
1985
1990
1995
2000

3. Serial Switched Fabric Technologies
Common characteristics of Technologies Unidirectional (duplex pair) - LVDS (Low Voltage Differential Signaling) - GHz raw link speed (10Gbps by bonding links) - Open market standards - Most are VXS (VITA 41) enabled Differences between Technologies InfiniBand is shipping in quantity, but limited market penetration - StarFabric is viable, but link speed limited to one-fourth of others - HyperTransport has achieved acceptance, but constrained to In-the-Box - RapidIO has both Serial and Parallel, but lacks silicon (some parallel) - PCI Express has PCI lineage/momentum, but no products until PCI Express Advanced Switching (AS) is not specified. - Gigabit Ethernet is TCP/IP leader, but stack is CPU intensive (Need TOE) Gigabit Ethernet products are now emerging.