[Bloat] ipspace.net: "QUEUING MECHANISMS IN MODERN SWITCHES", > (Jonathan Morton)
David Collier-Brown
davec-b at rogers.com
Wed May 28 13:29:15 EDT 2014
On 05/28/2014 11:33 AM, Jonathan Morton <chromatix99 at gmail.com> wrote
> It's a mathematical truth for any topology that you can reduce to a black box with one or more inputs and one output, which you call a "queue" and which *does
not discard* packets. Non-discarding queues don't exist in the real
world, of course.
>
> The intuitive proof is that every time you promote a packet to be transmitted earlier, you must demote one to be transmitted later. A non-FIFO queue tends to increase the maximum delay and decrease the minimum delay, but the average delay will remain constant.
A niggle: people working in queuing theory* make the simplifying
assumption that queues don't drop. When describing the real world, they
talk of "defections", the scenario where a human arrives at the tail of
the queue and "defects", either to another queue or to the exit door of
the store!
As you might guess, what I find intuitive the IP world finds wrong, and
vice versa.
--dave
[* as opposed, perhaps, to queuing networks (:-)]
--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
davecb at spamcop.net | -- Mark Twain
--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
davecb at spamcop.net | -- Mark Twain
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