[e2e] Open the floodgate - back to 1st principles

[Guy T Almes]

Alex,
  Right.
  I'm not yet to the point of saying that the rule of thumb is wrong 
(though I have my doubts), but *am* concerned that it may be passed down 
from the past without periodic reexamination.
  Regards,
        -- Guy

--On Sunday, April 25, 2004 21:59:41 -0700 Cannara <cannara at attglobal.net> 
wrote:

> Guy, I'll simply testify to hearing this from a variety of folks making
> routers a couple of years ago, even at the big C.  Maybe just a rule of
> thumb, passed down from the past.
>
> Alex
>
> Guy T Almes wrote:
>>
>> David,
>>   A very good question.
>>   I will attempt an answer, but those who were active in this area about
>> ten years ago should chime in.
>>   My impression is that, at least during the early 1990s and probably
>>   since then, there was a rule of thumb that a router should have a
>> delay-bandwidth worth of memory per output port.  This was understood to
>> be friendly to TCP in that it would allow the buffer to drain while the
>> TCP sender recovered itself from a stumble following the bursting of the
>> queue.
>>   This was during the time when high-speed wide-area meant T3 across the
>> country.
>>   This is not adequate to achieve the purpose then intended, at least not
>> in what would now pass as a high-speed wide-area path.  But it does add
>> to router cost.  I am honestly not sure if this rule of thumb is being
>> remembered correctly or if router designers examine it critically.
>>
>>   Regards,
>>         -- Guy
>
>