The Defense Switched Network By: DataStorm This is an extremely shortened tutorial on the DSN. More information is available through the DoD themselves and various places on the Internet. If you have any comments or suggestions, feel free to e-mail me. ***THE BASICS OF THE DSN*** Despite popular belief, the AUTOVON is gone, and a new DCS communication standard is in place, the DSN, or Defense Switched Network. The DSN is used for the communication of data and voice between various DoD installations in six world theaters: Canada, the Caribbean, the Continental United States (CONUS), Europe, the Pacific and Alaska, and Southwest Asia. The DSN is used for everything from video-teleconferencing, secure and insecure data and voice, and any other form of communication that can be transmitted over wiring. It is made up of the old AUTOVON system, the European telephone system, the Japanese and Korean telephone upgrades, the Oahu system, the DCTN, the DRSN, the Video Teleconferencing Network, and more. This makes the DSN incredibly large, which in turn makes it very useful. (See the section TRICKS in this article for more information.) The DSN is extremely isolated. It is designed to function even when outside communication lines have been destroyed and is not dependent on any outside equipment. It uses its own switching equipment, lines, phones, and other components. It has very little link to the outside world, since in a bombing/war, civilian telephone may be destroyed. This aspect, of course, also means that all regulation of the DSN is done by the government itself. When you enter the DSN network, you are messing with the big boys. To place a call to someone in the DSN, you must first dial the DSN access number, which lets you into the network itself. From there you can dial any number within the DSN, as long as it is not restricted from your calling area or hone. (Numbers both inside and outside the DSN can be restricted from calling certain numbers). If you are part of the DSN, you may periodically get a call from an operator, wanting to connect you with another person in or out of the network. To accept, you must tell her your name and local base telephone extension, your precedence, and any other information the operator feels she must have from you at that time. (I'm not sure of the operators abilities or technologies. They may have ANI in all or some areas.) The DSN uses signaling techniques similar to Bell, with a few differences. The dial tone is the same on both networks; the network is open and ready. When you call or are being called, a DSN phone will ring just like a Bell phone, with one difference. If the phone rings at a fairly normal rate, the call is of average precedence, or "Routine." If the ringing is fast, it is of higher precedence and importance. A busy signal indicates that the line is either busy, or DSN equipment is busy. Occasionally you may hear a tone called the "preempt" tone, which indicates that your call was booted off because one of higher precedence needed the line you were connected with. If you pick up the phone and hear an odd fluctuating tone, this means that a conference call is being conducted and you are to be included. As on many other large networks, the DSN uses different user classes to distinguish who is better than who, who gets precedence and more calls and who does not. The most powerful user class is the "Special C2" user. This fortunate military employee (or hacker?) has virtually unrestricted access to the system. The Special C2 user identifies himself as that through a validation process. The next class of user is the regular "C2" user. To qualify, you must have the requirements for C2 communications, but do not have to meet the requirements for the Special C2 user advantages. (These are users who coordinate military operations, forces, and important orders.) The last type of user is insensitively called the "Other User." This user has no need for Specail C2 or C2 communications, so he is not given them. A good comparison would be "root" for Special C2, "bin" for C2, and "guest" for other. The network is fairly secure and technologically advanced. Secure voice is encrypted with the STU-III. This is the third generation in a line of devices used to make encrypted voice, which is NOT considered data over the DSN. Networking through the DSN is done with regular IP version 4, unless classified, in which case Secret IP Routing Network(SIPRNET) protocol is used. Teleconferencing can be set up by the installation operator, and video teleconferencing is a common occurrence. The DSN is better than the old AUTOVON system in speed and quality, which allows it to take more advantage of these technologies. I'm sure that as we progress into faster transmission rates and higher technology, we will begin to see the DSN use more and more of what we see the good guys using on television. Precedence on the DSN fits the standard NCS requirements, so I will not talk about it in great detail in this article. All I think I have to clear up is that DSN phones do NOT use A, B, C, and D buttons as the phones in the AUTOVON did for precedence. Precedence is done completely with standard DTMF for efficiency. A DSN telephone directory is not distributed to the outside, mainly because of the cost and lack of interest. However, I have listed the NPA's for the different theaters. Notice that the DSN only covers major ally areas. You won't be able to connect to Russia with this system, sorry. Keep in mind that each base has their own operator, who for the intra-DSN circuit, is reachable by dialing "0." Here is a word of advice: there ARE people who sit around all day and monitor these lines. Further, you can be assured these are specialized teams that work special projects at the echelons above reality. This means that if you do something dumb on the DSN from a location they can trace back to you, you WILL be imprisoned. AREA DSN NPA Canada 312 CONUS 312 Caribbean 313 Europe 314 Pacific/Alaska 315/317 S.W. Asia 318 The format for a DSN number is NPA-XXX-YYYY, where XXX is the installation prefix (each installation has at least one of their own) and YYYY is the unique number assigned to each internal pair, which eventually leads to a phone. I'm not even going to bother with a list of numbers; there are just too many. Check http://www.tfs.net/~havok (my home page) for the official DSN directory and more information. DSN physical equipment is maintained and operated by a team of military specialists designed specifically for this task, (you won't see many Bell trucks around DSN areas). Through even my deepest research, I was unable to find any technical specifications on the hardware of the actual switch, although I suppose they run a commercial brand such as ESS 5. My resources were obscure in this area, to say the least. ***TRICKS*** Just like any other system in existence, the DSN has security holes and toys we all can have fun with. Here are a few. (If you find any more, drop me an e-mail.) * Operators are located on different pairs in each base; one can never tell before dialing exactly who is behind the other line. My best luck has been with XXX-0110 and XXX-0000. * To get their number in the DSN directory, DoD installations write to: HQ DISA, Code D322 11440 Isaac Newton Square Reston, VA 20190-5006 * Another interesting address: It seems that GTE Government Systems Corporation Information Systems Division 15000 Conference Center Drive Chantilly, VA 22021-3808 has quite a bit of involvement with the DSN and its documentation projects. ***IN CONCLUSION*** As the DSN grows, so does my fascination with the system. Watch for more articles about it. I would like to say a BIG thanks to someone who wishes to remain unknown, a special english teacher, and the DoD for making their information easy to get a hold of.