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Connection Caching and Little's Law

2011-08-18 20:32:41

Murray S. Kucherawy wrote:

I don't think the practice of connection caching is particularly selfish when compared to the cost of having the connection torn down and then re-established with some frequency, when it's generally much cheaper for both the sender and the receiver to just leave it open.

Only if there is efficient work being done. Look, maybe it was my fault to assume the obviousness of this classic Operational Research and Querying Design problem is commonly understood.

One just need to use Little's Law [1] to see how this is a very selfish queuing concept that benefits only one part of the system and increases demands and cost on other parts. This is particular true you reach a capacity and can no longer remain in steady state. To return it back to steady state, adjustments are needed. The flaw in CS is the erroneous presumption that there is unlimited resources on the receiver side (service workers) so that the waste in idle service time is factored out as arrival rates increased. As in a bank scenario, efficiency is lost if after a teller station finishes servicing a customer, he decides to hangs around the station doing nothing. The teller's time is wasted. Less workers available, Queued Customers wait longer, Lines get longer. Little's Law will show you this.

[1] http://en.wikipedia.org/wiki/Little's_law

--
Sincerely

Hector Santos
http://www.santronics.com


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