[ PROTOCOLS:OSDIR-4.TXT ] [ OJ, 5/86 ] THE UNDER SECRETARY OF DEFENSE WASHINGTON D.C 20301 14 May 1984 3 (C I) MEMORANDUM FOR SECRETARIES OF THE MILITARY DEPARTMENTS DIRECTORS OF THE DEFENSE AGENCIES DIRECTOR, JOINT STAFF, OJCS SUBJECT: DoD Policy on Defense Data Network (DDN) Protocols Under secretary of Defense (Research and Engineering) Memorandum "Defense Data Network (DDN) Implementation", dated 10 March 1983 prohibited the use of X.25 connections to the DDN until the DDN X.25 specifications had been approved by the DoD Protocol Standards Steering Group (PSSG). The DDN X.25 specification has been approved by the PSSG and it is hereby authorized for use on the DDN. The requirement to use the DoD Standard Host-to-Host Transmission Control and Internet Protocols (TCP/IP) promulgated by USDRE Memorandum, "DoD Policy on Standardization of Host-to-Host Protocols for Data Communications Networks," 23 March 1982, remains in effect. With the approval of the DDN X.25 specification in the Defense Communications Agency (P&SI) Memorandum, "DDN X.25 Specification", 4 January 1984, the DoD has taken another step toward standardized data communication protocols, along with industry and the international community. Since the use and availability of the X.25 protocol is widespread, every effort should be made to bring DoD in line with all the data communications users in this area. The DDN X.25 will be used as the access protocol; TCP and IP will continue to be used as the internet and transport layers. The 1822 protocol will continue to be supported by the DDN until phased out via evolution. All new systems and systems undergoing major redesign are required to use levels 2 and 3 of the DDN standard X.25 protocol for interfacing to the DDN. Case-by-case waivers will be considered by Assistant Secretary of Defense (C3I). The on-going I-S/A AMPE and BLACKER programs are specifically requested to take steps to implement the DDN Standard X.25 specification as early as possible. James P. Wade, Jr