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ZL3AI > TECH 21.12.05 01:38l 51 Lines 2022 Bytes #999 (0) @ WW
BID : 6971-ZL3AI
Read: DL1LCA GUEST OE7FMI
Subj: Re: A puzzling fault
Path: DB0FHN<DB0MRW<DB0HOT<DB0ERF<DB0FBB<DB0IUZ<DB0GOS<DB0RES<ON0AR<ZL2BAU
Sent: 051220/2333Z @:ZL2BAU.#73.NZL.OC #:27778 [Blenheim] $:6971-ZL3AI
From: ZL3AI@ZL2BAU.#73.NZL.OC
To : TECH@WW
From: ZL1ANM@ZL1AB.#11.NZL.OC
To : TECH@WW
>
>>From: K0CQ@W0AK.#CIA.IA.USA.NA
>>To : TECH@WW
>>
>>I have found through long experiments that unless a frequency is
>>totally private with only two users that I get more throughput
>>(as does bbs forwarding) if maxframe is set to 1 than when set to
>>7. That's because when there are collisions they almost always
>>are in the first frame and the protocol has no way of accepting
>>the other 6 good frames and asking for the first only to be sent.
>>The protocol can only reject that damaged frame and so all 7 get
>>sent again.
FlexNet and the more recent versions of TFPCX (and maybe TFX?) have what is
called a "frame sammler" which is like a buffer which temporarily stores
frames received after a missing one. When that missing one is received, the
rest are automatically added to the incoming stream. This can make a very
significant difference on a busy channel with collisions or when signals
are getting clobbered with QRM/QRN.
>Absolutely correct! With medium to heavy channel usage, uploading
>to the BBS will probably be most efficient with Maxframe set to 1.
>
>Unfortunately, many users including myself are using AGWPE in auto
>mode, which starts at Max=7 and adjusts itself downwards to not
>less than 3 according to channel congestion.
>
>AGWPE revises the setting every 2 minutes, so if you start up AGWPE
>and immediately try to upload a message, you can cause all kinds of
>havoc on the channel for the first two minutes. The same applies if
>you are in the habit (as I am) of turning down the receiver's audio
>while typing a message, and then try to upload.
>
>I guess I should experiment with non-auto mode and Max=1.
>
>73 de Neil ZL1ANM
FlexNet starts at a maxframe of 1 and if that has been successful for a few
frames it gradually increases maxframe up towards 7. If packets are
unsuccessful, the gaps between retries (i.e. FRACK) gradually increases so
as to minimise congestion.
73 David.
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