Utilizing Mesh Networks

[Maverick]

Has anyone here really used these effectively? I see apps such as FireChat etc, and the concept could prove to be quite useful in an emergency situation.

Here is a video that explains mesh-networks for those who aren't familiar.

VIDEO LINK

Say you're traveling with a group and one member has a sat-phone. Something bad happens and the cell networks become unusable, but you can get a message back to the guy who has the sat-phone via the mesh-network.

[CV]

Effectiveness is governed mostly by distance (transmit power).

Think of this as no different than walkie-talkies. The network (channel) allows you and your kids to communicate, and that communication is not governed by any other dependency (protocol).

I have setup ethernet-based mesh networks for field operations. Same principle, and not much different than a home network. All of your systems can communicate with each other, and independent of any external infrastructure. Communication is limited to the power of the routers/switches used but can be scaled to extend longer distances (wired or wireless).

Router A > Router B "Signal Good!
Router A > Router C "Weak Signal"
Router A > Router B > Router C "Good Copy!"

A, B, and C can communicate just fine, even though distance exists between A and C.

I hope this helps. Mesh networks are great for being off-net, but again, distance is the biggest factor.

[Sharky]

Depending on what you are dealing with, some are also "self healing". Meaning, if one of the nodes dies for some reason, the network is intelligent enough to realize that and re-route traffic around the dead node.

[The Fat Guy]

If this is in relation to what we have been discussing, you can see how CV's concept of distance plays in. You would have to establish a "cluster" of sorts comprised of nodes with limited distance / connectivity (Maybe even face to face) and connect the clusters with the one node that has the ability to span the distance to another similar node that in turn may serve a cluster of other nodes with limited distance / connectivity. Ideally, those nodes that communicate externally for each cluster would have to have an eventual path to the network hub/manager/control center.

Again, ideally, each main node from each cluster would like to have direct connectivity with the control center. Some may, however, have to connect like CV's example, A-B Good, A-C Bad, A-B-C good.

[Maverick]

TFG - Yes, this has to do with what we discussed before. I'm actually going to shoot you an email soon as well.

Distance definitely seems to be the main factor, as well as unreliability of the network existing (if using an existing app). So it sounds like for dependability, the best thing would be to set-up your own network? That may be a little out of reach for what I had in mind.

Better example of what I'm asking:

Let's say you and your family are traveling overseas. You're hanging out in the hotel room and your wife and kids went out shopping...while they're out in town, something goes boom and the cell and internet networks have gone down. Is there an existing mesh-network system that would allow for communication between you and your family? Are apps like FireChat popular enough? Does the tech exist to hop a message across signals without them needing the app? If this was something that is set-up independently using routers, what kind of distance can one expect to get out of a single router? I would assume it's the same distance and limitations as any other home WiFi setup.

[CV]

In ideal conditions, even WiFi (such as 802.11g, for example) is only effective up to 150 feet--and that's only if you're using a powered device such as a wireless switch. Your cell phone is significantly limited (again, due to power source) to about 30 feet.

The only way you'll be able to accomplish what you're looking for is to do so over existing infrastructure (cellular, et al.). Assuming exchanges get hosed during an act of terrorism, like 9/11, or any of the other mass-shootings, you're best bet is to go with SMS-based technologies. The irony being that SMS uses an unreliable protocol. During 9/11, SMS worked because everything else was shutdown due to over-use.

I can get more technical if needed. Feel free to ping if you need more.

[Maverick]

Originally Posted by CV

In ideal conditions, even WiFi (such as 802.11g, for example) is only effective up to 150 feet--and that's only if you're using a powered device such as a wireless switch. Your cell phone is significantly limited (again, due to power source) to about 30 feet.

The only way you'll be able to accomplish what you're looking for is to do so over existing infrastructure (cellular, et al.). Assuming exchanges get hosed during an act of terrorism, like 9/11, or any of the other mass-shootings, you're best bet is to go with SMS-based technologies. The irony being that SMS uses an unreliable protocol. During 9/11, SMS worked because everything else was shutdown due to over-use.

I can get more technical if needed. Feel free to ping if you need more.

Just so I'm translating this correctly because I'm still self-teaching myself a few things. Basically, in the event of an incident, mesh-networking capabilities are extremely limited without a pre-established infrastructure...especially over any distance. SMS is the way to go. I would ASSume keep the messages small and concise in order to keep the file size small. iPhone users traveling internationally should probably turn off iMessage so it doesn't attempt to use the data network? Or is that trivial?

You say SMS based technologies...are there any things I should be looking at other than just a cell phone that can send a text?

[CV]

Correct. Distance will be a factor without using some kind of infrastructure. On the other end, SMS requires infrastructure, but the technology runs parallel to voice, not with it. Meaning, when you send a SMS text message, it is sent to a special message center (SMSC) that stores then forwards it. If it doesn't send, it tries again after a short period. It's also stateless, so all messages are completely independent, and not reliant upon prior success.

SMS messages have to be small (140 characters or less). Interesting side-note: Twitter was originally based on SMS technology

iMessage is not based on SMS, and requires internet connectivity (WiFi).

As I mentioned previously, the irony is that SMS is inherently unreliable. Meaning, there's no way to know if your message was received. But, it's usually the best way to get a message out in the event of catastrophy.

[Tracy]

Originally Posted by Maverick

...Let's say you and your family are traveling overseas. You're hanging out in the hotel room and your wife and kids went out shopping...while they're out in town, something goes boom and the cell and internet networks have gone down. Is there an existing mesh-network system that would allow for communication between you and your family? Are apps like FireChat popular enough? Does the tech exist to hop a message across signals without them needing the app? If this was something that is set-up independently using routers, what kind of distance can one expect to get out of a single router? I would assume it's the same distance and limitations as any other home WiFi setup.

OK, if I understand correctly, you're mixing requirements with technology to find an answer; which I think is incorrect in this case.

Your requirement: Maintain communications with family/co-workers; in the event of a complete loss of cellular/internet connectivity; over distances ranging from 500 to 2000m.

Is there a system or technology base that can help re-establish comms?

Answer:

1. Amateur band radio handsets in the VHF (134-176 MHz) or UHF (400-470 MHz).

2. CB mobile (vehicle) radios.

3. If you want to couple your smart phone to a system, you could try this: GoTenna. GoTenna systems work without cellular or internet connectivity and can range as a far as six miles (outdoors in open terrain).

Does this help?

[Jim1348]

I tried the GoTenna and I was underwhelmed on their range. I was able to ping the other device reliably under 1 mile range. Time will tell if the soon to be released Beartooth devices have better range.

https://www.beartooth.com/

[Tracy]

Originally Posted by Jim1348

I tried the GoTenna and I was underwhelmed on their range. I was able to ping the other device reliably under 1 mile range. Time will tell if the soon to be released Beartooth devices have better range.

https://www.beartooth.com/

Beartooth may have the same characteristics as GoTenna.

Range is a function of line-of-sight. If your transmitter can't 'see' the receiver, then you're probably not going to make the connection. Higher ground or 'perches' can solve most communication problems.

Effective radiated power affects your signal strength, if you can 'see' your receiver.

Another factor is your receiver sensitivity. The better the sensitivity, the easier to pick up weak signals.

[zmtthw]

http://www.persistentsystems.com

[CV]

Originally Posted by zmtthw

http://www.persistentsystems.com

That looks very cool. I cringe at what the cost might be. Mostly because I want to play around with it

[Gray Rhyno]

Originally Posted by CV

That looks very cool. I cringe at what the cost might be. Mostly because I want to play around with it

Expensive. We've been experimenting with them at work.

EDIT: The frown face is in reference to the cost, not the ability of the gear. They provide transmission paths we couldn't get any other way, but I am personally unsure if the cost/benefit ratio is worth it.

[Sharky]

Originally Posted by CV

That looks very cool. I cringe at what the cost might be. Mostly because I want to play around with it

Yeah at my old job we used a similar radio that is a direct competitor to PS and those radios ran about $10K each. The cloning station was around $25K. They worked as advertised, but they are definitely not priced for private use.