[aprssig] Ideal Digipeater Behavior

[John Langner WB2OSZ]

Thanks for trying to clarify this.  

Just a couple quick observations.  It will take longer to go through all of
the examples.


> All digipeaters must implement 30 second duplicate suppression. No
digipeater
> may transmit the same (source address, information field) twice in any 30
> second window.

Duplicate suppression is based on source address, destination address, and
information field.   In other words, everything other than the via path
which changes along the way.


> # The WIDE1-1 alias gets replaced with LOWDIG-1 and is marked as used
> TRACKR-5>APZTST,WIDE1-1 ->
>  TRACKR-5>APZTST,LOWDIG-1*

Yes!
"Replace" when hop count is used up (i.e. -n has been decremented down to
zero).   "Insert" own call when hops remain.
Some implementations will both insert their own call and leave the used up
alias to produce this:

TRACKR-5>APZTST,LOWDIG-1,WIDE1*

This is confusing and ambiguous.  It looks like the packet was digipeated
twice.  Once by a digipeater that implements tracing (inserting its own
callsign) and again by another digipeater which did not identify itself.