Gary - Thanks much for the info on the switching chips. I tracked down a data sheet on the Prizma, but it seems that there has been a 4X improvement in chip performance since you last looked (the Prizma E). The new numbers seem to match the NN numbers too (2x28 = 50 and 454.4 Gbps)
A once-over lightly info piece is given at: zurich.ibm.com
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Characteristics of Prizma-E include:
16 input ports
16 output ports
1.6 - 1.8 Gbps per port
QoS: up to four priorities
Built-in support for modular growth in number of ports
Built-in support for modular growth in port speed
Built-in support for modular growth in aggregate throughput
Built-in support for automatic load-sharing
Self-routing switch element
Dynamically shared-output buffered element
Built-in multicast and broadcast
Aggregate data rate 28 Gbit/s per module
3.8 Million transistors on chip
624 I/O pins
Prizma has built-in the hardware support to built such switch systems easily. This is the preferred method to build, e.g., switches for port speeds of 622 Mbps and 2.488 Gbps. Assuming a 400 Mbit/s port speed for a single switch module (original Prizma chip), the paralleling of only two [original] modules would be sufficient to build a 622 Mbit/s switch. Two Prizma-E will support 3.6 Gps/port.
lagaude.ibm.com
PRIZMA Scalable Packet Switch Technology
PRIZMA is a very high-performance,
protocol independent, IBM developed
technology that uniquely supports Fast
Ethernet, Gigabit Ethernet, ATM, Fiber
Channel and Token Ring.
IBM's PRIZMA offering includes
subsystems, companion chips,
software and a test tool. At the chip level,
PRIZMA is available with throughput rates of
6.4Gbps scalable to 102.4Gbps in
single-stage expansion. The new PRIZMA-E
chip provides throughput from 28.4Gbps to
454.4Gbps also for single stage switches.
Using multi-stage expansion PRIZMA can
scale to provide terabit systems. PRIZMA's
flexibility includes switching variable size
packets, scaling to support the number of
ports and expanding port speeds.
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See also mini data sheets at:
lagaude.ibm.com |
