[ih] Secret precedence schemes back then

[David Mills]

Jack,

The fuzzies had two throttles, one the current window size, the other 
the number of outstanding packets. That number was monitored not to 
exceed eight in view of the limited number of packet buffers in Ginny's 
gateways. When a source quench arrived, that number was reduced on the 
expectaion that Ginny or the fuzzies would hurl a source quench. So far 
as I remember, Ginny never did, but the fuzzaies did.

It was an interesting time. Ginny was stuck with a real resource hog 
(Elf?) with a maximum throughtput of 10 pkt/s, but the fuzzies had much 
more memory and a throughput of 300 pkt/s.

Jack Haverty wrote:

>On Tue, 2009-01-27 at 21:14 +0000, David Mills wrote:
>  
>
>>but so far as I knew, nobody but the Fuzzballs 
>>actuall responded to source quencn. 
>>    
>>
>
>Errr, ummm, well...depends on what you mean by "respond".
>
>Since Source Quench was sent by a receiver when it had gotten so
>overwhelmed that it threw away your packet, the obvious response from
>the Sender was to re-send the packet immediately, since you had just
>been told that it had been discarded.
>
>I can't remember exactly what the various TCP implementations did that I
>was involved in.  Or I could take the fifth amendment...
>
>Of course, the spec might have said something a bit different about what
>a well-behaved TCP should do when you received a Source Quench.  But I
>don't recall there ever being any "certification" or the like that any
>particular implementation was behaving correctly.  As I remember, the
>spec wasn't very specific.  E.G., If you send one packet and get a
>Source Quench back, what does it mean to "throttle back".
>
>And of course I can't remember whether the core gateways put such
>"control" traffic at the front of the queue (it's important stuff!), or
>discarded it (gaaak, more whining and noise from that complainer
>host...).  Or whether they looked at all.  Possibly all three schemes,
>over time.
>
>Of course, this whole Internet thing was a research project that was
>supposed to go away and be replaced by the "real" system using ISO and
>CCITT technology.
>
>Good thing it's been 23+ years Dave!
>
>/Jack
>
>
>  
>