Bulldozer00's Blog

The figure below models an N node, “Enterprise Bus” (EB) connected, software-centric system.

Even though the “shared” EB supplies a raw, theoretical bandwidth of 1 Gbps to its connected user set, contention for frequent but temporary control of the bus among its clients increases as the number of message publisher (pubber) clients increases. Thus, the total effective bandwidth of the system as a whole decreases below the raw 1 Gbps rate as its utilization increases.

In the example, instead of accommodating up to 10, 100 Mbps clients, the increasing “back pressure” exerted by the bus under the duress imposed by multiple, “talky” (you know, wife-like) clients will throttle the per-pubber message send rate to well below 100 Mbps.

I recently found this out the hard way – through time-consuming testing and making sense out of the “unexpected” results I was getting. Bummer.