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OH1KH > BPQ 07.04.97 22:33l 112 Lines 3449 Bytes #-10800 (0) @ EU
BID : OH1KH7372
Read: SP6RYB GUEST
Subj: Speed up
Path: DB0AAB<DB0AHO<DB0MWS<DB0LAN<DB0ABH<DB0SRS<DB0ZDF<DB0GE<LX0PAC<ON7RC<
ON1BWP<ON6AR<PI8HWB<PI8VAD<PI8VNW<OH7RBA<OH1AI<OH1RBU<OH1RBF
Sent: 970407/1744Z @:OH1RBF.#POR.FIN.EU #:18185 $:OH1KH7372
From: OH1KH@OH1RBF.#POR.FIN.EU
To : BPQ@EU
Hi !
We are running here FBB/DXc/BPQ system with several BPQkiss and Thenet (x1jr4)
ports.
I have tried to speed up 9k6 user link and managed to do something but
it is not perfect yet.
I'm talking now a SIMPLEX (70cm) user port with radio speed at 9600bps,
no other traffic present (one user connected).
Hardware side there is:
PC/BPQ------------------Thenet/TNC2-->radio
RS232/19200bps 8MHz
TheNet Should have Maxframe 7 to maximize databits compared to flags/control
bits. (to get out 7 packets with one Txdelay(+turn_around_times)).
How ever, TheNet will NEVER send 7 frames to user at one turn (from FBB/BPQ)
if the L4WINDOW at BPQ and(/or) Thenet is configured less than 7.
As the parameter L4W will be compared to both ends value at the time the l4
link is set up, both sides should have equal window size (otherwise the
lower value is selected).
Knowing the problem of running short of buffers (if heavy traffic) I have
set L4WINDOW to be double of MAXFRAME. I.E. it is now 14.
With that, I can force TheNet send full 7-packet bursts at time.
It works also reverse, I can now push data to FBB at mean rate of 730cps
(measured from 1Mb file upload, on empty channel, simplex).
Taking (downloading) data from FBB gives speeds around 650-700cps during
same conditions as above.
But now we come to THE POINT ! This downloading speed is true ONLY
files with size about 15-20kb or less !!!!
If file is longer something happens somewhere. I suspect BPQ ! If I
have long file, the first 15-20k comes with nice speed. Then I can
no more get full 7packet bursts. Further on file comes with 1-4
packet bursts till the end dropping the speed to around 230cps or so.
I have used same values also to 1200cps user ports. Those are done
with multidropped BPQkiss/TNC2 hardware.
I have had same kind of reports from users there: When they download
bigger files, the first 10-20k comes nice 80-90cps (maxframe4/1200bps/simplex)
but after that speed drops down (i.e they are not getting full 4packet
bursts any more).
I have also written a program that uses BPQHOST and allows downloading.
Same effect (maybe even worse)! (so it can not be between FBB and BPQ).
What I like to know is: Have someone else noticed same kind of effects?
Is there a "known problem" with BPQ ?
Have someone else worked out how to get maximum
speeds out from similar systems ? (parameters??)
BTW uploading, as said, goes fine at speed 730cps but while doing so and
connecting to BPQ with another call one can see (using "S") that BPQ's
buffers are VERY low (11 to 15 or so).(what I said about making big L4W!)
This makes a "side effect" where all other connections via BPQ are
slowing down. (Why one user gets most of buffers? if L4W is 14 shoud this
user take something like 14 buffers,too !?!? Now it seems to be 140 rather
than 14!)
Seems that BPQ has not enough buffers AND/OR cannot handle them
right at all times.
Any comments ?
ÛÛÛÛÛÛÛÛÛÛÛÛ 73'Saku OH1KH
°°°°°°°°°°°°Û
°ÉÍËÍ»°°°°°°Û @ OH1RBF.#POR.FIN.EU (sysop)
°°°º°ºº°°°°°Û @ KO25.SPACE
°°°º°Èΰ°°°°Û
°°°º°°º°°°°°Û oh1kh@megabaud.fi
°°°°°1.5à24°Û
°°°°°°°°°°°°
T4 1.5à24
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