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Date:      Sun, 08 Jun 1997 11:50:50 -0400
From:      Dennis <dennis@etinc.com>
To:        Manar Hussain <manar@ivision.co.uk>
Cc:        isp@freebsd.org
Subject:   Re: ETinc's Bandwidth limiter
Message-ID:  <3.0.32.19970608115040.006b1a80@etinc.com>

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At 03:46 PM 6/8/97 +0100, you wrote:
>>> There is no "fair routing" in a web farm unless everyone pays the same
>>> price, which is ridiculous. Charge based on their bandwidth access
>>> capability..
>>> and with the bandwidth manager there is not accounting headaches 'cause
>>> they cant get more than they pay for.
>>
>>Dennis, this sounds like an overstatement. Fair does not necessarily
>>mean 'all equals', there can be different weights for different
>>users depending on how much they pay for, and the fairness is in
>>making everyone get what he pays for.  Hard limiting the bw for
>>each user as you seem to suggest prevents eveyone from taking
>>advantage of statistical multiplexing, which, given the burstiness
>>of network traffic, is very rewarding for all.

The BurstManager takes care of that aspect....but with heavy usage 
hard limits are the only way to guarantee "fairness". Otherwise you
just have a crapshoot.

And this also depends on what you are selling. If you are selling 56kbs
access,
the "hard limits" simulate putting their server on a 56kbs connection,
which is
exactly what they expect, and exactly what they are paying for.  The
BurstManager
only enforces the limits when a certain threshold is met, which lets you
have your
cake and eat it too.

Your "statistical multiplexing" statement is interesting, because the fact
that it is
inherently *unfair* is exactly why you need a bandwidth manager.

>
>Exactly. There are a whole host of ways I can fairly happily limit each
>hosts bandwidth if I'm not bothered by these limits being "soft". The aim
>of the game is to be able to confidently offer a minimum level of service
>(which they can specify and thus pay for) but let people make more out of
>it if they can. 

Which you can only do if you have a lot more bandwidth than you need with
soft limits.

The other problem with bandd that I see is that you are indirectly cheating
everyone
because its likely to totally pig-out your machine under load. Of course if
you only
plan on having a few customers then this is not a factor.

Dennis



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