[aprssig] Re: WIDEn-N and the New Paradigm for UIDIGI

[Robert Bruninga]

Henk,

I keep forgetting about the difference in Europe
and the USA.  Maybe with the Large N paths
used in Europe, you DO need this kind of enforced
prevention of multiple strings of WIDEn-N,WIDEn-N.

In fact, since DIGI_NED is so smart, why not make
the rule simply be that only WIDEn-N as a SECOND
or more field in a digi path is ignored if the preceeding
path is also a WIDEn-N..  This prevents any
multiple WIDEn-N,WIDEn-N abuse.  Of course,
you do have to allow for WIDE1-1,WIDE2-1...

Bob


>>> henk.de.groot at hetnet.nl 5/15/2005 11:21:55 AM >>>
Hello Bob,

Robert Bruninga schreef:
> WIDE2-2  original
> WIDE2-1  1st hop
> WIDE2     2nd hop
> WIDE2*   3rd hop but only by another UIDIGI ROM
> 
> Now that the WIDE2 will be marked as used on its
> first appearance, this also solves that problem too.

In the rules I published for DIGI_NED I leave the last WIDE2 unmarked.

Reason is to terminate packets like:

USER>APRS,WIDE2-2,WIDE2-2

Now after the 2nd hop the packet will have become:

USER>APRS,DIGI1*,DIGI2*,WIDE2,WIDE2-2

The assumption is that no digi will take WIDE2 and this will render the

rest of the path (the next WIDE2-2) useless and therefore avoids QRM.
But 
of course this only works if no digi responds to an unmarked WIDE2 with

zero SSID.

Question is if I should leave it this way. There are a few other
options.

An option is it to rewite the whole path, which will strip any
additional 
calls in the path. So after the first hop the packet above becomes:

USER>APRS,DIGI1*,WIDE2-1

Any trailing calls are removed. Reason I do not like this is because I

want to keep trailing NOGATE and RFONLY calls that may appear in the
path 
like this:

USER>APRS,WIDE2-2,RFONLY

rewriting the whole path looses those calls too.

A third option is to rename WIDE2 at the last hop to avoid any DIGI to
act 
on it, for example name it WIDE2T.

So I have 4 options to choose from:

1) Classic: Leave a WIDE2*, this will work but does not prevent abuse
due 
to mutilple WIDE2-2's in the path, the 2nd hop packet looks like this:

    USER>APRS,DIGI1*,DIGI2*,WIDE2*,<remaining calls>

2) Leave the WIDE2 unmarked - the majority of digipeaters will leave it

alone, but not all, the 2nd hop packet looks like this:

    USER>APRS,DIGI1*,DIGI2*,WIDE2,<remaining calls>

3) Leave a WIDE2* and strip any remaining calls (including RFONLY and 
NOGATE), the 2nd hop packet looks like this:

    USER>APRS,DIGI1*,DIGI2*,WIDE2*

4) On the last hop leave an unmarked WIDE2T (WIDE2 Terminated), no digi

will recognize that and the remainder of the path is not used any
furter 
by any digipeater.

    USER>APRS,DIGI1*,DIGI2*,WIDE2T,<remaining calls>

What do you think is the best option? Currently I used option 2) but as
I 
see this will sometimes not prevent further processing of the packet.
What 
does the Kantronics firmware do? I like option 4 the most since it
works 
everywhere, but it is DIGI_NED specific as no TNC can do the same
thing.

Kind regards,

Henk.




_______________________________________________
aprssig mailing list
aprssig at lists.tapr.org 
https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig