DSN is not exactly what I would refer to as tapping into the local telco. DSN (Defense Switched Network) replaced AUTOVON (Automatic Voice network in the mid to late 1980s and through the early 90s). AUTOVON was set up to principally be a voice only network, and in many case over analog switch facilities. DSN converted it over to all diigital, and included voice, video, and data over the same trunks.
The key difference between DSN and a regular commercial call is they go over different trunks and they terminate at DSN compliant switches. There are several things different about DSN compliant switches, but the key difference is the use of precedence, and precedence codes. They have no real counterpart in a commercial trunk, other than an operator interrupt for an emergency. With DSN, the end user can preempt a trunk and knock another user off the line with the proper precedence level. Some folks out there who know their RFCs and remember the early 760 series standards may recognize those precedence levels. They are: FLASH OVERRIDE (FO) -FO takes precedence over and preempts all calls on the DSN and is not preemptible. FO is reserved for the President of the United States, Secretary of Defense, Chairman of the Joint Chiefs of Staff, chiefs of military services, and others as specified by the President. FLASH (F) -FLASH calls override lower precedence calls and can be preempted by FLASH OVERRIDE only. Some of the uses for FLASH are initial enemy contact, major strategic decisions of great urgency, and presidential action notices essential to national survival during attack or preattack conditions. IMMEDIATE (1) -IMMEDIATE precedence preempts PRIORITY and ROUTINE calls and is reserved for calls pertaining to situations that gravely affect the security of the United States. Examples of IMMEDIATE calls are enemy contact, intelligence essential to national security, widespread civil disturbance, and vital information concerning aircraft, spacecraft, or missile operations. PRIORITY (P) -PRIORITY precedence is for calls requiring expeditious action or furnishing essential information for the conduct of government operations. Examples of PRIORITY calls are intelligence; movement of naval, air, and ground forces; and important information concerning administrative military support functions. ROUTINE (R) -ROUTINE precedence is for official government communications that require rapid transmission by telephone. These calls do not require preferential handling. When I was involved in DSN communications in Europe, my unit had a Flash precedence phone line, mainly because we had a special mission (which is about all I can say). We had the capability of bumping everybody off the DSN network save for the CINC US Army Europe and a few other folks. You will most likely have to deal with the issue of precedence. Also, access to a commercial line is normally done with dialing a 9 first (typical for trunk access); DSN usually uses an 8 - Your mileage may vary; check your local listings. Finally, DSN uses a slightly different dial plan than the rest of the universe (go figure:-) While you may be able to access the US with a country code of 001, or Germany with a country code of 49, that's not how it's done with DSN. Access is determined by regions, and each region has its own "country code". The regions are: Canadian Section Caribbean Section CONUS Section European Section Pacific/Alaska Section Southwest Asia Section All of the above information is public knowledge and freely available. Anything more is likely classified, and not subject to posting on this list. In case it isn't already clear at this point, DSN is totally separate from the PSTN. HTH, Paul Werner > I am working on an IP telephony solution and I need to hook in to the > DSN. > From my current understanding DSN is sent out to the local telco via the > PSTN and is routed from there. This would make for a fairly simple dial > plan > in Call Manager. Has anybody heard anything different about how DSN is > setup to work? ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=29851&t=29805 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
