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[aprssig] Packet routing, path specification.

Wes Johnston aprs at kd4rdb.com
Thu Jun 23 19:34:24 UTC 2005


Specifying a path of NSR is craziness... what happens when NSR mobiles
wander out of range of their NSR area?  The existing WIDE digi's won't
respond to them.  One of the slick things about NSR is that it allows
the continued use of the legacy WIDEn-n path element.

The more correct thing to do is to have NSR digipeaters respond to
packets with paths containing:
-RELAY
-WIDE
-TRACE
-WIDEn-n
-no path specified

Packets which contain a path with one or more elements that do not
contain any of the above aliases will not be tampered with.

I get the feeling that the resistance to NSR is the giving up of control
for one-off situations.  Bob hit the nail on the head by saying that one
of the perks of ham radio is the ability to adapt under varying
circumstances.  But sometimes control is too much bother.  As an
example, I use DHCP at home for all my devices that I hook to my LAN.  I
_could_ use static IPs (and sometimes do), but for 99% of my
applications DHCP fits the bill.  The important thing is that the
_ability_ to use static IPs is there if I need it.  Same goes for NSR...
if NSR could allow the average user "plug and play" coverage, and still
provide a back door way for the power users to do what they need, we'd
have a winner.

What the APRS on-air network has devolved into is a system that is open
for abuse either willfully (those running paths like WIDE7-7,RELAY),
absent mindedly (those running WIDE5-5 and forget to change paths as
they enter a populated area), or those who  out of appathy just set and
forget their path.  There are a few "power users" who know what they are
doing and they should be able to flag their packets somehow to prevent
the network from modifying their packets.  Now, seriously, I wonder how
much better a power user's chance of getting his specifically routed
packet thru the network would be if by and large, the rest of the users
were corralled into smaller, better managed boxes?  Which, by the way is
where most of us want to be.  For the most part, I just want my tracker
to be seen at findu... but there are times when I'd like to go
further.... and in every case that Bob has mentioned going further, it
was to a place that he knew the callsigns of the digi's and could (and
did) specify a path.

I think there is room within the NSR spec to 1)control the network to
prevent abusive paths or at least limit the damage to one or two
digipeaters, 2) provide automatic pruning down of the area covered,
3)allow the power users the elbow room to tinker.

Wes

Robert Bruninga wrote:

>>>>wa7nwp at jnos.org 06/23/05 12:10 PM >>>
>>>>        
>>>>
>>Would it be possible to do both?   Client 
>>stations could choose either an outgoing 
>>NSR path (an anti-path) or a legacy path as needed?
>>    
>>
>
>Yes, I think the two can co-exist.  Just name 
>the PATH as "NSR" and that then gives your packet
>over to the NSR system and it will route it
>according to the NSR's sysop's design. 
>
>Of course this waters down its potential, because its 
>biggest advantage was to be able to prevent users 
>from abusing their freedome to choose their own path.
>
>But I would have no problems with it at all under
>these general rules:
>
>1) A user can send a WIDE2-2 anywhere and
>    WILL get 1 or 2 hops out of it guarnateed. 
>    ( THe  APRS default path)...
>
>2) A user can send ANY length D1,D2,D3 directed
>    path (since even a full 7 hop path is less total
>    copies on the network than a single W2-2) and
>   is an inconsequential load on the system, but
>   permits the users the flexibility to handle
>   unusual needs.
>
>Any other path will be at the mercy of the NSR
>sysop.  Or just select the path of "NSR" for
>full NSR routing.
>
>Bob
>  
>
>>>>wa7nwp at jnos.org 06/23/05 12:10 PM >>>
>>>>        
>>>>
>On Thu, 23 Jun 2005, Robert Bruninga wrote:
>
>  
>
>>>to effectively implement the NSR algorithm.
>>>      
>>>
>>...
>>
>>I fully suport the APRS-IS, and global messaging
>>via the internet, but it being able to use a reasonable
>>RF path as needed where needed is the essence of
>>HAM radio in my mind.  There is a big difference between
>>the distribution needs of APRS 24/7 home stations just 
>>doing nothing all day versus a real-live-HAM radio
>>activity with humans at both ends...
>>    
>>
>
>Would it be possible to do both?   Client stations
>could choose either an outgoing NSR path (an anti-path)
>or a legacy path as needed?
>
>Bill - WA7NWP
>
>
>
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