Downloaded from http://www.everyspec.com MIL-STD-187-31O ● 14 OCTOBER 1976 MILITARY STANDARD STANDARDS FOR 10NG HAUL COMMUNICATIONS ● SWITCHING PLANNING STANDARDS FOR THE DEFENSE COMMUNICATIONS SYSTEM SLHC Downloaded from http://www.everyspec.com MIL-STD-187-31O DEPARTMENTOF DEFENSE WASHINGTON, D. C. 20306 Switching Planning Standards for the Defense Communications System MIL-STD-187-31O 1. This Military Standard is approved for use by all Departments and Agencies of the Department of Defense . 2. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document, should be addressed to Director, DefenseCommunicationsEngineeringCenter, ATTN : Code M1O, 1860 Wiehle Avenue, Reston, Virginia 22090, by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. ii Downloaded from http://www.everyspec.com MIL-STD-187-31O FOREW08D 1. Electrical performance standards for the Defense Communications Systsm (DCS) are contained in the MIL-STD-188-1OO and 300 series of documents. These standards, which apply primarily to today’s analog system, contain performance values which must be within the state-of- the-art and based on measured performance of actual equipment and circuits . Since standards are the basis for specifying equipmsnt to be procured or reprocured for use in the DCS, they provids assurance that new equipment will perform satisfactorily and interface properly with other equipment in the DCS. 2. At present, the standardization coverage of the DCS is fairly com- prehensive. lhis is due to the relatively stable configuration of the DCS since completion of the major switched subsystems, which has per- mit ted standards development to “catchup.” Currently, however, the DoD is entering a period, of perhaps ten years or more, during which mnny major changes are planned in the DCS. Unless some modification is made to the DoD standards program, standards will continue to be developed essentially after-the-fact, and will be of little help in planning and designing these forthcoming changes. Accordingly, the standardization effort is being expanded to include the development of “future” or planning standdrds for the DCS. These standards are being developed at an earlier date than, and are to be forerunners of, conventional standards. 3. DCS Planning Standards contain characteristics which apply to the evolving and future DC S. Performance values assigned to these charac- teristics may meet the same criteria as conventional standards, i.e. , proven by measured performance, etc. , or they may be based on best technical judgment of what is needed for the future. In some cases, performance values have not been determined as yet and their definition maY depend upon the completion of related studies or 8DT&E programa. This category of unknown performance values serves to idsntify and, in a sense, reserve these areas until agreed-upon values can be established. This tends to preclude unilateral decisions by designers that might preempt the opportunity of making a better choice later on. 4. Planning standards provide uniform guidance for the design of the evolving and future DCS. Providing this guidance at the concept engineering stage will help to minimize ineffective designs and costly fnteroperability problems at later stages of implementation, as well as assuring utilization of appropriate advances in technology. Also , establishing a reference source of design guidance will: minimize unilateral design dec:lsionsby one project engineering group; pinpoint areas where design decisions are needed; facilitate the comparison and iii Downloaded from http://www.everyspec.com MIL-STD-187-31O evaluation of design criteria in regard to tradeoffs and impact on other subsystems and overall system performance; and provide wider exposure of design decisions’ to all interested DoD activities. 5. The need for inceroperability with other DoD and non-DoD systems has been a major consideration in the development of planning stan- dards. Specifications for the characteristics and parameters in the planning standards were developed considering present specifications and future plans for the TRI-TAC system, commercial systems (both national and international), and NATO/NICS. Also considered was the Final Report of the DoD Commit tee on Interoperability and DoD, national and international communication system standards. 6. It is planned to develop planning standards in the following areas: a. Network and System Design b. Switthing c. Secure Communications d. Transmission e. Satellites f. Terminals g. System Management and Centrol h. Survivability. ‘Ibisplanning standard, for switching, is the first to be developed. An analysis has been made of the evolving and future DCS, as planned, to determine what switching planning standards are needed. Services and features which will differ from those in the present DCS, thereby requiring new design effort or design decisions, have been identified and broken down into specific subject areas, characteristics, and parameters. Technical descriptions of these characteristics and parameters have been prepared which represent a technical snapshot of where DCA/DoD stands in defininglspecifying them for the evolving and future DCS. 7. In order to provide a reference for the switching planning stan- dard, a description of the evolving and future DCS, together with the aforementioned analysis, is provided and is divided into time periods. The first time period applies “to the Nominal Future DCS, which is a configuration based on logical extensions of ongoing pro- grams; i.e. Phase II Secure Voice, AUTODIN II, and a DCS-suitable AN/TTc-39 . This period is considered herein as the 1976-1986 time iv Downloaded from http://www.everyspec.com MIL-STD-187-31O period, although full implementation of these programs may extend beyond 1986. The second period applies to the Future DCS - Advanced Concepts, the definition of which depends on the ability to take advantage of evolving technologies. This period is considered the post-1986 time period, although advanced concepts could be implemented earlier. Switching planning standards applicable to the post-1986 time period will be based on the results of advanced R6D pertaining to a unified switch. This will provide a frame of reference for judging performance requirements or acceptability of intermediate switching applications; e.g. AN/TTC-39. Downloaded from http://www.everyspec.com MIL-STD-187-31O CONTENTS i“m.EwoRD CONTENTS CHAPTER 1. SCOPE 1-1 2. REFERENCED DOCUMENTS 2-1 3. TEF44s, DEFINITIONS Am ACRONYMS 3-1 4. THE PRESENT DCS 4-1 5. THE FUTURE DCS 5-1 6. CIRCUIT SWITCHING 6-O-1 SECTION 1 - NUMSERING HAN 6-1-1 SECTION 2 - SERVICE FEATURES 6-2-1 SECTION 3 - INFORMATION TONES AND RECOROEO ANNOUNCEMENTS 6-3-1 SECTION 4 - SIGNALING AND SUPERVIS ION 6-4-1 SECTION 5 - ROUTING 6-5-1 SECTION 6 - INTERFACES 6-6-1 SECTION 7 - CIRCUIT SWITCH CHARACTERISTICS - OVERSEAS 6-7-1 SECTION 8 - CIRCUIT SWITCH CHARACTERISTIC S - CONUS 6-S-1 vi Downloaded from http://www.everyspec.com MIL-STD-187-31O CONTENTS - Cant inued 233E CHAPTER 7. DATA SWITCHING 7-o-1 SECTION 1 - SYSTEM PERFORMANCE REQUIREK2NTS 7-1-1 SECTION 2 - FUNCTIONAL REQUIREMENTS 7-2-1 SECTION 3 - PROTOCOLS 7-3-1 SECTION 4 - PACXET SWITCH CHARACTERISTICS 74-1 SECTION 5 - AUTODIN II SYSTE?lCONTROL 7-5-1 SECTION 6 - AuTOD2N II SOFTWARE 7-6-1 8. ACCESS AREA 8-o-1 SECTION 1 - DIGITAL ACCESS EXCHANGE (DAX) 8-1-1 ● SECTION 2 - LOCAL DIGITAL MES SAGE EXCHANGE (LDMX) 8-2-1 B’ECTION 3 - COMMUNICATIONS ACCESS PROCESSOR (CAP) 8-3-1 SECTION 4 - PRIVATE AUTOMATIC BRANCH EXCHANGE (PABX) 8-4-1 SECTION 5 - COMMUNICATIONS SELECTOR SWITCH (CSS) 8-5-1 SECTION 6 - INTERPACES 8-6-1 9. SYSTEM CONTROL ELSMENTS APPLICABLE TO SWITCHING 9-o 10. FUTURE DCS - ADVANCSD CONCEPTS 104-1 SECTION 1 - UNIFIED DIGITAL SWITCH (UDS) 10-1-1 SECTION 2 - SOFTWARE 10-2-1 vii Downloaded from http://www.everyspec.com MIL-STD-187-31O FIGURES EK!+ Figure 5.1 Future DCS Generic Configuration 5-7 6.1.1 Message Format for Call Initiate 6-1-11 To Be Used by Switches with CCS 6.1.2 Message Format for Call Initiate 6-1-12 to be Used by Switches with Digital In-Band Signaling 6.4.1 Trunk Signal ing Buffer 64-3 6.4.2 MUX/DRMOX Subchannel Allocations 6-4-4 6.4.3 Format of Call Initiate Message 6-4-6 6.4.4 Format of Call Complete Message 6-4-7 6.4.5 Format of Call Answer, Release, 6-4-7 Call Incomplete (Except Invalid Route) , Trunk Test, and Special Mes sages 6.4.6 Format of Acknowledgment and Test 6-4-8 Sync Messages 6.4.7 Format of Invalid Route Message 6-4-8 6.4.8 Format of Sync A and Sync B Messages 6-4-8 6.4.9 Typical Message Sequence 6-4-12 6.5.1 Basic Pattern of Polygrid Network Structure 6-5-2 6.5.2 Home Grid Array 6-5-3 6.5.3 Order of Trunk Group Cluster Selection 6-5-13 7.2.1 Standard Interface Between Data 7-2-10 Terminal Bquipment and Data Communicantion Equipment 7.3.1 Protocol Structure 7-3-2 7.3.2 Binary Segment Leader 7-3-6 7.3.3 Effect of Line Modes 7-3-7 7.3.4 Type A Binary Segment Leader Mode VI 7-3-8 7.3.5 Procese-To-Process Transfer of Information 7-3-12 7.3.6 Type B - Packed Binary Segment 7-3-15 Leader/Mode I 7.5.1 System Control General Message Format 7-5-4 8.1.1 DAX System Concept 8-1-2 10.1.1 Frequency-Time Representations 10-1-12 10.1.2 Multiplex Structure for Typical Frame Period 10-1-13 10.1.3 Functional Structure for Future Switch 10-1-16 Architecture viii Downloaded from http://www.everyspec.com MIL-STD-18 7-310 L 1ST OF TABLES