[aprssig] NETROM Throughput?

[John D. Hays]

Direwolf 1.5 has a duplex mode, so a test harness should be easier to build.

On Sat, Mar 3, 2018 at 1:22 PM, Robert Bruninga <bruninga at usna.edu> wrote:

> Ancient Packet Question:
>
> For a long string of NETROM nodes operating on alternating A/B BANDS (full
> duplex), would throughput be efficient or would ACKS from the next digi
> collide with incoming traffic from the previous one?
>
> Consider a string of 9 nodes in a row:
>
> --1--  --2--  --3--   --4--  --5--  --6--  --7--   --8--   --9--
> TXA   RXA  TXA   RXA  TXA   RXA   TXA   RXA   TXA
> RXB  TXB   RXB  TXB   RXB   TXB   RXB   TXB   RXB
>
> If I remember conventional traffic, a sending station will send up to
> seven packets in a single transmission and, on a half duplex channel,  the
> ACKing station will ack the last one he got correct..  But if it is a full
> duplex channel, would the single incoming transmission of 7 packets be
> generating a continuous stream of all seven acks since the receiving node
> does not have to wait for the channel to clear?  What setting tells it to
> wait to see if there are more packets before originating a single ack?
>
> It would seem that for only a few packets (all fitting in a single
> transmission) that the bulk of traffic might ripple quickly along the
> chain.  But as soon as more traffic was pending at the source, or a
> continuous feed of traffic, that things would clog up quickly.  Then this
> might be no better than all TX/RX on a single frequency half duplex anyway.
>
> Or is max throughput only possible with every link having a clear frequency
>
> ---1---   ----2----    ----3----    ------4-----   ----5----
> -----6-----    ----7-----
> TXA     RXA/RXB     TXB        RXB/RXC     TXC        RXC/RXA      TXA
>    RXC    TXC       RXC/RXA      TXA        RXA/RXB     TXB         RXB/RXC
>
> I guess I never ever operated conventional packet over full duplex links
> and so have no basis for thinking it through..
>
> Bob, WB4aPR
>
>
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>


-- 

------------------------------
John D. Hays
Edmonds, WA
K7VE

   <http://k7ve.org/blog>  <http://twitter.com/#!/john_hays>
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