[HamWAN PSDR] 44.x.x.x HamWAN network at Paine

Sun Apr 27 22:59:12 PDT 2014

All that routing stuff is at a layer higher than I was meaning to ask about.

PtMP is just short hand for Point to Multi-Point communication.

In the two modes of operation you outlined, it seems to me it's possible 
for 2 mobile stations to communicate with 1 common fixed station by 
simply transmitting packets that bear either a common 2-digit code, or 
contain the fixed station's callsign.  Is the fixed station capable of 
sending responses addressed distinctly to each of the 2 mobile 
stations?  Is the addressing doable on a per-packet basis, or would the 
fixed radio need to be re-programmed with a new destination address 
(callsign) or something?  Can it simply transmit a frame bearing the 
common 2-digit code and all stations in earshot will receive it?

In terms of multiplexing, how does any station know when it is OK to 
transmit?  Is there a CSMA scheme or is it just an immediate 
transmission when data comes in?  Is there something more advanced, like 
ARQ?

In the above scenario, are the 2 mobile stations able to communicate 
directly between each other?  (assuming all nodes can hear each other here)

--Bart

On 4/27/2014 6:48 PM, Dean Gibson AE7Q wrote:
> I had to Google to find out what P2MP was, but in my VERY brief Google 
> education on the subject, I don't think it applies.
>
> The radio doesn't multiplex anything.
>
> The consumer-grade routers I own (Linksys BEFSR41, Netgear WGT624v2) 
> seem to have no way to turn off NAT.  dd-wrt is not possible with the 
> BEFSR41;  it is "work-in-progress" for the WGT624v2.  NAT seems to 
> make routing issues a little more complex to think through.  Both 
> routers have the ability to specify a "DMZ host", but I think that 
> just turns on universal NAT to that host. Both routers have the 
> capability of manually adding entries to a static routing table, but I 
> don't know if that skips over the NAT.  If we have to have NAT, it 
> seems to me that the best way to set up the router is with the radio 
> connected to the LAN side (with whatever private IP address we want), 
> and have the WAN side connected to the 44.x.x.x network.  That allows 
> incoming (ie, via the radio)  packets to go wherever they can and 
> responses to come back; whereas orienting the router the other way 
> (unless we use the "DMZ host" feature) doesn't.  I suppose I could 
> donate one of my (very) elderly (2005) Dell PowerEdge 1650 1U servers 
> to the effort, but that seems like a bit of overkill ...
>
> What I think would be a good idea is to meet and discuss this 
> face-to-face (pretty much anytime) with diagrams, rather than 
> shoveling eMails back and forth.  Scott, if your schedule permits, you 
> are more than welcome.
>
> -- Dean
>
> ps: Scott, I plan to come to the DEM on Tuesday to start on this, 
> unless you're not going to be there, or other conditions (like ongoing 
> slide work) make it a bad idea.
>
> On 2014-04-27 12:06, Bart Kus wrote:
>> OK, we can slap some extra security on there.  Shouldn't need an 
>> extra router for that.
>>
>> What about the PtMP story?  One of the advantages you mentioned 
>> (Dean) was mobile access.  Can it multiplex access somehow?
>>
>> --Bart
>>
>>
>> On 4/27/2014 9:53 AM, Dean Gibson AE7Q wrote:
>>> Exactly (or the equivalent).
>>>
>>> On 2014-04-27 09:34, John Hays wrote:
>>>> It should be on a dedicated router on its own segment.
>>>>
>>>> Sent from my iPhone
>>>>
>>>> On Apr 27, 2014, at 9:27 AM, Dean Gibson AE7Q <hamwan at ae7q.com 
>>>> <mailto:hamwan at ae7q.com>> wrote:
>>>>
>>>>> The only "authentication" the radio has, are the following:
>>>>>
>>>>>  1. The radio can be set to only receive remote transmissions that
>>>>>     include a two-digit decimal code; *or*
>>>>>  2. The radio can be set to only receive remote transmissions that
>>>>>     are addressed to the callsign programmed into the receiving
>>>>>     radio (I would recommend this setting).
>>>>>
>>>>> Any other authentication would have to be provided by a router or 
>>>>> firewall.
>>>>>
>>>>> On 2014-04-26 22:39, Bart Kus wrote:
>>>>>> Any packets on that LAN are considered trusted since they passed 
>>>>>> authentication.  What's the auth story on the 23cm modems?
>>>>>>
>>>>>> --Bart
>>>>>>
>>>>>> On 4/26/2014 10:37 PM, Tom Hayward wrote:
>>>>>>> On Sat, Apr 26, 2014 at 9:26 PM, Dean Gibson AE7Q 
>>>>>>> <hamwan at ae7q.com> wrote:
>>>>>>>> At the Snohomish County DEM, place a router (or bridge) between 
>>>>>>>> the ID-1 and the 44.24.240.x network.
>>>>>>>> In this scenario, the ID-1 located at my house would also be 
>>>>>>>> connected to a router that acts as though it were directly 
>>>>>>>> connected to the 44.24.240.x (or any other) network at the DEM.
>>>>>>> We have a router at Snohomish County DEM with an extra port that 
>>>>>>> could be used for this. The subnet there is 44.24.240.128/28. We 
>>>>>>> have another subnet of address pairs set aside for 
>>>>>>> router-to-router links. So as far as networking goes, we could 
>>>>>>> execute your plan. I can't commend about the feasibility of any 
>>>>>>> of the other bits.
>>>>>>>
>>>>>>> Tom 
>>>
>>>
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