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This is a guide for anybody who is a participant in a Distributed Alert Network (DAN).
Distributed Alert Network Guide (DANG)
Distributed Alert Network (DAN)
What is a Distributed Alert Network or DAN? It is a network of people that have a common interest. They use the network to share news and other information related to that common interest.A person can be a member of one DAN, more than one, or none at all. It depends on how many interests he or she has, and how many of those interests have DANs.
What makes the Distributed Alert Network special is its resistance to damage. No single person manages the whole network. Each person in the network manages only a tiny part of it, his neighborhood, in cooperation with his neighbors. If any person in the network becomes unable to participate then that person's neighbors know how to repair the network and continue operating without that person. They do this themselves using their Distributed Alert Network Guide (DANG), without the help of any central manager.
Because of its ability to self-repair, a DAN is particularly useful when reliability and security are important. They can be used for Publication By Sneaker Net, mutual aid societies, Leaderless Resistance movements, and other activities.
Small DANs
A small DAN is one with 5 members or less.Suppose that Alice wants to be part of a Distributed Alert Network of people that share an interest of hers. But she doesn't yet know anybody else who wants to be in it. Until she does, she can create a network of one person, herself.
AliceAdding a person in a small network is easy. You simply link up the new person with everybody else.For example, suppose Alice meets Billy and discovers that Billy shares Alice's interest, and Billy wants to join her network. The network might become:
Billy | | | | | | | | | | AliceThe positions in these diagrams correspond roughly with the positions these people would have on a map. Map positions and distances become important when a network has more than 5 members.Now suppose Alice meets Carol, who also wants to join. The network might become:
Billy | \ | \ | \ | \ | \ | \ | \ | \ | \ | \ Alice ------- CarolA 4th person, David joins the network. The network might become:
Billy / | \ / | \ / | \ / | \ / | \ / | \ / | \ / | \ / | \ / | \ David ------- Alice ------- Carol \ / \ / +--------------------+A 5th person, Ellen joins the network. The network might become:
Billy / |\ \ / | \ \ / | \ \ / | \ \ / | \ \ / | | \ / | | \ / | | \ / +--------|----|---+ \ / / | | \ \ David ------- Alice -|---- Carol \ | | / \ | | / \ | | / \ | | / \ | | / \ | / / \ | / / \ | / / \ | / / \ |/ / EllenLarge DANs
Linking every network member directly to every other member as in Small DANs is not practical in Large DANs. Here are some guidelines for structuring and managing your network neighborhood if you are in a Large DAN, which is a DAN with more than 5 members.
- 1. If possible then have exactly 4 network neighbors.
- 2. If possible then choose neighbors that are spread around the compass dial. With a perfect spread there would be 90 degrees between adjacent neighbors.
- 3. If possible then have neighbors who are network members that are physically close to you.
Here are the reasons for these above guidelines.
1. Having exactly 4 network neighbors, instead of some other number, is recommended for the following reasons:
- 0 neighbors means that the network can have only 1 member. This is not very useful.
- 1 neighbor means that the network can have only 2 members. This also is not very useful.
- 2 neighbors means that the network can have any number of members, but the network would be basicly a big ring. This would work okay if everybody lived on the shore of a large desert island, but most of us don't. We live in towns, states, and nations, which are 2-dimensional surfaces.
- 3 neighbors works for 2 dimensional surfaces. It also works for 3 dimensional spaces such as high rise apartment buildings. But it won't work if the number of network members is odd, because each member has 3 half-links, and the total number of half-links in a network must be even.
- 4 neighbors also works for both surfaces and spaces. But it is better than 3 neighbors because it works regardless of whether the number of members is even or odd.
- 5, 7, 9, and higher odd numbers of neighbors have the same problem as 3 neighbors. They don't work if the number of network members is odd,
- 6, 8, 10, and higher even numbers of neighbors also work regardless of whether the number of members is even or odd. But they aren't as good as 4 neighbors because there are more neighbors that must be remembered.
Therefore, having 4 neighbors is the best.
2. Spreading your neighbors around the compass dial is recommended because it helps spread information in all directions.
3. Choosing neighbors that are physically closer is recommended because:
- Passing messages is faster, costs less, is more reliable, and is more secure when distances are smaller.
- Most news is local news.
Remember that being and having a neighbor means that you are part of a voluntary relationship. For a particular person to be your neighbor, both you and that person must want it that way.
Adding Somebody To The Network
Adding a person to a network with 5 or more neighbors is more complex, but only a little.Suppose Alice meets Frank, who wants to join the network shown in the previous diagram. Here is that diagram again, with Frank shown unconnected in the lower left corner.
Billy / |\ \ / | \ \ / | \ \ / | \ \ / | \ \ / | | \ / | | \ / --------|----|--- \ / / | | \ \ / / | | \ \ David ------ Alice -|---- Carol \ | | / \ | | / \ | | / \ | | / \ | | / \ | / / \ | / / \ | / / \ | / / \ |/ / Frank EllenHere is how the network could be reorganized to include Frank.Billy / /|\ / / | \ / / | \ / / | \ / / | \ / | | | / | | | / --------|----|--- / / | | | \ / / | | | \ David--------Alice--|-----Carol | | | | / / | / | | / / | / ----|----|--- / | / / | | / | / / | | / | / / | / / | / / | / / | / / | / / | / / | / / |/ / |/ / Frank---------EllenNote that David is no longer directly connected to Ellen, and Billy is no longer directly connected to Carol. But they are connected indirectly through other neighbors. Each member has exactly 4 neighbors.Lets assume the network grows much larger, and the following diagram illustrates a small piece of it. The unterminated lines at the edges represent links to other network members.
| | | | | | | | | | | | ----Glenn---------Billy---------Harry---------James---- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ----David---------Alice---------Carol---------Kenny---- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ----Frank---------Ellen---------Irene---------Lenny---- | | | | | | | | | | | |Assume that Mitch wants to join and he lives bewween Glenn, Billy, David, and Alice. Mitch could be linked in this way.| | | | | | | | | | | | ----Glenn---------Billy---------Harry---------James---- \ / | | \ / | | \ / | | \ / | | Mitch | | / \ | | / \ | | / \ | | / \ | | / \ | | ----David---------Alice---------Carol---------Kenny---- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ----Frank---------Ellen---------Irene---------Lenny---- | | | | | | | | | | | |Removing Somebody From The Network
Sometimes is necessary to remove a member from a network. This can happen when a member goes away on vacation, moves away permanently, or dies. Sometimes a member doesn't physically go anywhere, but misbehaves somehow, and his neighbors decide to remove him.Removing a person from a network is similar to adding one. You follow the structuring guidelines.
Lets assume that the network appears as in the previous diagram, but Carol is moving away. She needs to be removed from the network, or at least from this part of it.
Here is how the network might appear with Carol removed.
| | | | | | | | | | | | ----Glenn---------Billy---------Harry---------James---- \ / / | \ / / | \ / / | \ / / | Mitch / | / \ / | / \ / | / \ / | / \ / | / \ / | ----David---------Alice Kenny---- | | / | | | / | | | / | | | / | | | / | | | / | | | / | | | / | | | / | | | / | ----Frank---------Ellen---------Irene---------Lenny---- | | | | | | | | | | | |Here is another way:| | | | | | | | | | | | ----Glenn---------Billy---------Harry---------James---- \ / \ | \ / \ | \ / \ | \ / \ | Mitch \ | / \ \ | / \ \ | / \ \ | / \ \ | / \ \ | ----David---------Alice Kenny---- | | \ | | | \ | | | \ | | | \ | | | \ | | | \ | | | \ | | | \ | | | \ | | | \ | ----Frank---------Ellen---------Irene---------Lenny---- | | | | | | | | | | | |Note that both networks follow the guidelines in that every network member has exactly 4 different network neighbors.DAN Messages
There are 2 types of DAN messages:
Broadcast Messages.
This is the most common type. These messages are used to disperse information throughout a part or all of the network. They include news, event notifications, and general calls for help.When a member receives a broadcast message, he should pass the message to all his neighbors except the neighbor from which he received it. But he shouldn't pass it outside its geographic limit if it has one. For example, if the message is of interest to only residents of a particular town, then it probably shouldn't be passed to members outside of the town.
Point-to-point Messages.
These type of message is rare. Its most common use is when a member is moving from one location to another, and wants to be connected to the network at his new location.When a member receives a point-to-point message, he should pass the message to the neighbor that moves the message closest to its final destination.
Combining Two Networks
Sometimes two networks with the same interest, or two parts of the same network, will grow in a way that they overlap each other, but are not aware of each other. There is nothing wrong with this, but if they were combined with each other then the members would have much closer network neighbors.Here is a diagram showing the situation of two overlapping networks. One network contains: Glenn, Harry, Frank, Irene, and others not shown. The other network contains: Alice, Kenny, James, Lenny, and others not shown.
| | | | | | | | | | | | | | | | | | | | -----Glenn-------Harry----------- | | | | | | | | | | | | | | | | | | | | -----------Alice-------Kenny----- | | | | | | | | | | | | | | | | | | | | -----Frank-------Irene----------- | | | | | | | | | | | | | | | | | | | | ----------James-------Lenny----- | | | | | | | | | | | | | | | | | | | |Here is a diagram showing one way that those two networks might be combined into one.| / | / | / | / | / | / | / | / |/ |/ -----Glenn Harry \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / -----------Alice Kenny----- / / / / / / / / / / -----Frank Irene----------- / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ James Lenny----- /| /| / | / | / | / | / | / | / | / |Note that each of the 8 members in the diagram continue to have exactly 4 neighbors, and links to the 16 members outside the diagram are maintained.Members don't need to see all of both networks to combine them. Each member restructures only that members's local neighborhood, neighbors within a 2 link distance. The process starts with the first two members that learn of the existence of the other member's network. As knowledge of the existence of the other networks spreads, the restructuring spreads. The restructuring stops when it has spread as far as it can go.
When A Member Moves
Generally 2 things should happen when a network member moves:
- First, the member must be removed from the network at his old address. This can be done by the member notifying his immediate neighbors of the date when he will be moving away. At the appropriate time, his neighbors follow the procedure for Removing Somebody From The Network.
- Second, the member should be added to the network at his new address. This can be done by sending a point-to-point DAN Message to the mover's new address expressing the desire to be added there. The message will stop at the network member closest to the new address, who will make contact at the appropriate time, and follow the procedure for Adding Somebody To The Network to add the mover to the network.
Know Your Neighbors
Nobody knows every member of the network. There's no need to. In fact, there are good security reasons why nobody should.But knowing your immediate network neighbors is highly recommended. You need to know them to pass messages to them. And they need to know you for the same reason.
At minimum, you should know how to communicate with your immediate neighbors. You should know multiple ways, so if one way isn't usable then you can use another.
Here are some of the things about your network neighbors that would be good to know.
- home address
- work address
- home telephone number
- work telephone number
- hours of availability in various locations
- cell phone number
- e-mail address
- 2-way radio channels monitored (CB, GMRS/FRS, direct connect cell phone; keeping in mind that others can hear you)
You should also know how to contact the neighbors of your neighbors. You will need to do this if one of your immediate neighbors needs to be removed from the network. To remove a neighbor you need to know that neighbor's neighbors.
DAN Usage Guidelines
Here are some basic guidelines for using a DAN.
- Send messages relevant to the network's interest. Don't send spam.
- If you receive spam from a neighbor, point that out to him, and don't forward it. Each member can function as a spam filter, because each member knows what's of interest to the group.
- If a member is engaging in behavior not in the interest of the group, and refuses to correct that behavior, then contact his neighbors and propose removing him from the network.
- If you discover that you forwarded a message that was bogus in some way, then send another message to retract the first one. Label the retraction message with a high priority. The high priority message should travel faster than the regular original, eventually catch up with it, and stop its progress.
- Keep in touch with your network neighbors. If there is no message traffic on the network, then contact your neighbors anyway to make certain that the communication links to them continue to work, and that none of your neighbors have disappeared.
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