Directional data flow over radio

[Cableguy]

Firstly, I'm not a networking expert.   I'm trying to setup a radio connection between (2) PCs with directional data flow (see diagram).  The PCs and radio modules have static IPs  Is there a way to utilize an Ethernet switch to direct the flow of data to/from the radio modules?

 

Any help here would be appreciated.

Thanks

[schizznick]

Ethernet by nature is bi-directional. I don't know of any way or switch that can only send or receive out a port and especially separate that info to 2 ports. It's possible using some wifi gear to set up one pair of Point to Point wireless as transmit and another as receive in order to essentially have full duplex wireless, Mikrotik, for example, can do this.

[beersykins]

I feel like IP is too high up the stack to try to combine these together, you'd need to IP route each of those hosts, which is a no go for most switches.  

[Cableguy]

So, it sounds like I need a "Router" instead of a "Switch" to do this function?  Can a Router be configured to direct to ports based on something other than IP number?

 

[schizznick]

The issue really isn't a router or a switch, but ethernet itself. I don't think any solution will break up traffic this way. Now it's possible building a device from scratch with custom software this may be possible, or using something like Linux with custom software running a routing engine may also work. Your biggest hurdle is that Ethernet is bi directional by nature!

[Cableguy]

OK.  So I need to find an embedded router project (IE: Rasberry Pi, Arduino, etc.) that I can change the router table/rules for my requirements?

[Alex Atkin UK]

The real question is WHY do you want to do this?

 

For optimum performance over wireless its really just about buying the best devices for the job using the optimum frequency for what you are trying to achieve.  What you are proposing just comes across as reinventing the wheel.

[Cableguy]

Good question.  For optimum radio performance, we have to stay within the FCC rules of max RF transmit power.  Using a typical transceiver style IP radio (WiFi), the radio will be transmitting and receiving.  The FCC will limit the amount of RF gain that can be used on transmitter antennae, but not on receivers.  By using a transmitter and receiver setup, we can maximize the antenna gain on the TX to FCC limits and get much higher gain on the receiver antenna.  Overall, this approach will provide much higher performing radio solution than the normal WiFi - as long as you can live with directional antennae.  

[beersykins]

What kind of distance are you looking at?

[Alex Atkin UK]

I'm not sure that would even work, as whilever you are using a standard WiFi protocol then surely it will stick to the same limitations?

I was thinking, with a router on both sides of the link you "might" be able to restrict traffic to specific radios but again I'm not sure this will have any real-world improvement, if anything it just complicates the network.

 

Basically what was thinking is that each radio would be a static route and then have firewall rules specify that incoming goes through one, and outgoing through the other.  But nothing is going to prevent all traffic in the other direction (the WiFi protocol itself I would imagine sends ACK packets back the other way to confirm receipt) which might negate the whole point.

 

Is this an indoor or outdoor link though?  Because if its outdoor you would probably get far better results from a commercial solution.

[schizznick]

I will reiterate, that the real problem is you will be fighting the ethernet standard the whole way as it was not designed to work like that. The best solution would be to utilize hardware that can already do that and tune it to your needs. Many companies have solid solutions for this type of setup and they have put the R&D into getting the best performance. I have seen WISP's get over a gig of speed at 30km utilizing off the shelf equipment. Maybe with more info on your goal and usage case we can make some better recommendations.

[Alex Atkin UK]

That's why I queried if its intended to connect buildings as Ubiquity have some nice equipment that I use myself to get a link between buildings on a 5Ghz frequency that is not typically used indoors, so you get very good speeds and latency.  I didn't even bother to put the second unit outdoors as its such a short range it gets a "good enough" link through a fairly beefy double wall with the second unit just sat on top of a cabinet.

 

They also have even beefier kit that uses 3Ghz, 11Ghz or 24Ghz, not typically used in the consumer space so even less likely to suffer from interference.  Although the top-end is generally intended for long links but it DOES offer full-duplex operation. https://www.ubnt.com/airfiber/airfiber24-hd/