Standalone Mobile Messenger

I propose to consider a prototype of the deployment of a mobile messenger (cloud in your pocket), allowing you to organize communication in an area that does not have the infrastructure of traditional data networks, as well as a private network that only users can access and data should be transmitted via secure communication channels. At the same time, mobility means a laptop for communicating with an installed messenger client. Using a mobile phone is possible with the further implementation of the concept.

In today's technological community, messaging over a messenger, as a rule, boils down to transferring data to a single data server (star topology), thereby imposing the following restrictions on the freedom of communication:

1. Be sure to have a server. In the traditional sense, this is either a server of a large online messenger (WhatsApp, telegram, sms, ICQ). Or it is a small PC subnet server using small applications and a standard exchange protocol (ICQ, jabber, etc.). At the same time, the server provides not only the retransmission of the packet from the sender to the addressee, but also useful features such as: storing the message until the client exits to the network, logging, mass sending, a single list of network contacts and so on.
2. The presence of computer networks, read routers, routers, access points, cell phone towers, organizing or giving access to a single local / global network. This infrastructure in the first place costs relatively a lot of money, and secondly it is stationary, that is, its deployment is done once and for a long time, and, as a rule, for big money. And in the third requires experience and skills of its administration.

I will give some examples:

1. A team of 10 people left for the area remote from civilization to perform some kind of work. This can be as a team of geologists, miners, a group of students for an internship or a mobile office of the organization’s employees. On the ground, it is necessary to quickly deploy a network for communication between team members, while taking into account that they can go on assignments, for example, up to 10 km.
2. You went to rest on a tourist base with your friends in separate houses or even tents. You need to deploy a mobile network to communicate and transfer some data.

Thus, taking into account the above, I will list the following criteria, which a mobile local area network should meet:
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• Low data rate. The implication is the transfer of text messages without media files.
• Compactness. Devices should be lightweight and heavy.
• Autonomy. Devices need to consume a small amount of power, allowing them to be powered by USB or portable batteries.
• Wireless . Data transmission should be carried out via wireless data transmission channels.
• Security Data channels must be protected from unauthorized access.
• Price. The entire set of equipment should cost no more than the equipment for the organization of the IP network.
• Ease of use. Network deployment should be limited to pressing a couple of buttons and entering a username and password.
• The range of the transmitted signal. The range of transmission over wireless channels should be provided not only due to the output power and channel width, but also the ability to build a mesh data network that allows messages to be relayed between subscribers, thereby creating a virtually unlimited coverage area. The same WI-FI is designed to work indoors up to 30 meters, and Bluetooth is designed for accessories in total.
• Access to the global network. The possibility of access to a single global Internet network, if any.

As a similar messenger, I suggest the following system concept:

1. Message server Although it is a disadvantage of the classical solution, it gives obvious advantages. Therefore, it is proposed not to get rid of it by moving to p2p, and using a mini PC like Rasbery or Beaglebone as a server. Basic requirements: the presence of external buttons, OS linux, the presence of indicators, as well as the ability to connect a radio interface for data transmission. Jabber can be used as a message server. Mini PC preferably with built-in battery.
2. RF-USB stick with mesh generation function, it is proposed to use 6LoWPAN. This technology allows you to get an ipv6 network from a mesh network as a client PC network interface. A huge plus is that it allows you to customize some of its parts, thereby adapting to the task being solved. As a client, it is proposed to use the free spark program. Radio should be used with a frequency of 433 MHz.
3. For the future. WI-FI RF433 access point / repeater with autonomous power for connecting portable equipment not via USB, but via wifi.

I suggest the following usage scenario:

1. You connect to the mini server via Ethernet, enter its admin panel and use the web of the muzzle once to set the necessary parameters for the messaging server and the mesh network.
2. To connect a client to a mesh network, it is suggested that its USB key fob be plugged into the server and press the “connect” button, after which the network parameters will be recorded in the key fob for further work in it.
3. Turn on the USB laptop / PC keychains from the radio and connect to the jabber server, first specifying the server settings in the client.
4. Update the contact list on the client and start exchanging messages.

Everything. This network can now always be carried with you and included regardless of the current location in the customer space. The network will automatically build the correct topology and clients connect to the server.

So far this is just a concept dictated by personal need for such a system. I suggest the community discuss the pros and cons, and answer the question: “Do we need it?”.