Saturday, September 14, 2013

HSMM-MESH a.k.a. "Broadband-Hamnet"

Sorry that I haven't posted in a while.  Life has been very busy with shake-ups both personally and professionally.  Things are kind of in flux just now but hopefully I can get back to a semi-regular posting schedule.  For now though, here is a compilation of some posts that I've made to our local hsmm-mesh Facebook group.  For those wondering, you can learn more about hsmm-mesh here.

September 7 at 12:59pm
Got one of my additional routers in. A WRT54GL, got it flashed and a mini mesh created. Also got in touch with a rep from TerraWave/Tessco, a company that manufactures outdoor WiFI antennas and got them to commit to sending us some free antennas. Getting four or five omnis from them hopefully coming this week.

September 3 at 6:51pm
Just found these on eBay. Would really come in handy to powering a WRT54G that is co-located with the antenna!

September 10 at 8:27pm
So I still haven't seen the other two routers yet, but I've managed to find some time to work with the two that I have. I've gotten Asterisk running on the R-Pi correctly again (the flash card got corrupted by not shutting down properly) and have two extensions running using Cisco 7961 VoIP phones with a SIP image on them, running one phone per mesh node. I also have a Grandstream HT-286 ATA that I will throw into the mix as soon as another router gets here.

The process is fairly simple as far as the hsmm router configuration is concerned. All that is needed is to edit the /etc/dnsmasq.conf to make DSNMasq hand out the proper DHCP options. Simply add the following to that file:


Replace x.x.x.x with the proper IP addresses of course. Option 150 specifies the TFTP server that the phones will use to download their images and config files. Option 120 points out the SIP server itself, and option 42 points to an NTP server.

If using an R-Pi, keep in mind that it does not have an onboard RTC, so you will need to point to something that can provide the proper time (or use a script as a work-around to set the time on boot, but there are obvious drawbacks to doing that).

One thing that I did notice is that we will want to plan out our subnetting scheme. The method employed by the hsmm image is neat, but not extensible in a large mesh.

Now to find the time to look into how QoS is handled, as well as multicast traffic. Those two things are important on any WiFi network and especially so on a mesh where you lose half of your bandwidth with each RF hop.

I've included a picture showing the two mesh nodes on top of my workbench with the two phones under their respective node. Audio quality was excellent, which I would expect with the two routers less than two feet apart.

Hopefully Terrawave/Tessco will ship those antennas soon. I should have at least one to spare and will throw it and any additional up for grabs when it gets here.

September 11 at 11:10pm
I'm *still* waiting on the two additional routers and five antennas to arrive, but I've been able to get a little done while I'm waiting. It is frustrating only have an hour or so per night to work on this after the kids go to bed.

I've managed to get an additional two phones and a sidecar for the main phone. They are all set up to call each other, as well as some outside agencies. I even added a little personal touch to the phones.

The speed-dials listed as "RF TAC x" will be for extensions that connect to phonepatches via an ATA. This would enable incident commanders to be able to talk via a phone to multiple groups on different radio systems or frequencies. This is a homebrew version of the Cisco IPICS solution that is used by Cisco TACOPS on deployment. Obviously intended to be used only by licensed individuals unless during an actual life-safety emergency.

Currently it is receive only via the internet for the 147.120 stream as I don't have the phone patches built yet, and would need radios for them to connect to as well. But once the proof of concept is done the rest is just "wash-rinse-repeat", right?

I also have an IP camera with environmental sensors running via the mesh as well. This would enable remote observation of triage areas or supply distribution points. It isn't weatherproof, but is fairly sturdy.

My goal is to have deployable go-kits each with a mesh AP, phone, camera, and switch for data connectivity built and ready for the October installfest.

There are other posts, I will have to go back through it and grab some more.  I also have non-hsmm stuff to share.  I got the Rockmite-40 built, as well as a Pixie II (that I recently gave to a ham that lost his gear in a divorce), with build pictures of both.  I also built a go-kit for mt FT-840 that my son and I took to the WMA a while back that I would like to share pictures of.  And I just acquired an FT-817 that will be fodder for some future posts.  Hopefully I'll have time and inclination to get the posts up.


Richard, KK4JDO

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