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

[Cannara]

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