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[aprssig] A wish for the next TM-D710A firmware update

Bob Bruninga bruninga at usna.edu
Wed May 21 01:59:34 UTC 2008


> It might even be cool to have something like this:
> If the DigiMeter (packets decoded) is low, 
> and you're not receiving many packets at all, 
> throw in an extra posit some short time period 
> after successfully decoding a packet.

We looked at this in the early days and *rejected* it completely as being a timebomb waiting to happen!  What this kind of approach overlooks is that by counting *decoded* packets, a very empty channel is completely indistinguishible from a totally saturated one.

This is because there are few decoded packets on a saturated channel just like there is on a lightly loaded one.   So we adamantly rejected ANY "network decisions" that were ever based on "decoded packet counting".  Absolutely this must be avoided.

It is a classic melt-down scenario as fewer packets get through, then these algorithms try harder, further bringing the network to its knees.  We categorically reject any algorithms that try harder when they get low success packets.

THis is because there are lots of scenarios where someone is not hearing or decoding packets and increasing his rate is exactly the wrong thing to do (for everyone else)..

Bob, WB4APR




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