1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-1000602.1996(R2014) Integrated Services Digital Network (ISDN) Data-Link Layer Signaling Specification for Application at the User-Network Interface As a leading technology and solutions development organization, ATIS brings together the top gl
2、obal ICT companies to advance the industrys most-pressing business priorities. Through ATIS committees and forums, nearly 200 companies address cloud services, device solutions, emergency services, M2M communications, cyber security, ehealth, network evolution, quality of service, billing support, o
3、perations, and more. These priorities follow a fast-track development lifecycle from design and innovation through solutions that include standards, specifications, requirements, business use cases, software toolkits, and interoperability testing. ATIS is accredited by the American National Standard
4、s Institute (ANSI). ATIS is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a founding Partner of oneM2M, a member and major U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications sectors, and a member of the Inte
5、r-American Telecommunication Commission (CITEL). For more information, visit. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Conse
6、nsus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and ob
7、jections be considered, and that a concerted effort be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or u
8、sing products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an inter
9、pretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or
10、 withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American
11、National Standards Institute. Notice of Disclaimer restart T200; andATIS-1000602.1996 5 7) On page 40 of Q.921, paragraph 2 of clause 5.6.7 shall be modified to read: If timer T200 expires, the data link entity shall: if it is not in the timer recovery condition, enter the timer recovery condition a
12、nd reset the retransmission count variable; if it is already in the timer recovery condition, add one to its retransmission count variable, and continue as indicated below. 8) On page 40 of Q.921, item a) under paragraph 3 of clause 5.6.7 shall be modified to read: a) if the value of the retransmiss
13、ion count variable is less than N200: restart T200; and either transmit an appropriate supervisory command (see note 2 in 5.6.5) with a P bit set to 1; or retransmit the last transmitted I frame V(S) - 1 with the P bit set to 1; or 9) On page 42 of Q.921, item a) under paragraph 1 of clause 5.8.5 sh
14、all be modified to read: a) the receipt of an undefined or unimplemented frame (see 3.6.1, third paragraph); 10) Annexes A, B, C, D, and E are informative and are not an integral part of this recommendation. 11) On page 54 of Q.921, the SDL in figure B.4/Q.921 (sheet 1 of 2) shall be replaced with t
15、he SDL shown in Figure 1. ATIS-1000602.1996 6 4 TEI ASSIGNEDDL-ESTABLISH requestMDL-REMOVE requestPERSISTENT DEACTIVATIONSABME DISCESTABLISH DATA LINKDISCARD UI QUEUEDISCARD UI QUEUEF = P F = PSET LAYER 3 INITIATEDABLE TO ESTABLISHTX DMTX UACLEAR EXCEPTION CONDITIONSV(S) = 0 V(A) = 0 V(R) = 0DL-ESTA
16、BLISH indicationSTART T2037 MULTIPLE FRAME ESTABLISHEDTX DM4 TEI ASSIGNED4 TEI ASSIGNED1 TEI UNASSIGNED4 TEI ASSIGNED4 TEI ASSIGNEDDL-RELEASE requestDL-RELEASE confirm5 AWAITING ESTABLISHMENTNoYesNoteNOTE Implementation option when implementing backup D-channel procedures for non-facility associated signaling Figure 1 Replacement for figure B.4/Q.921 (sheet 1 of 2) ATIS-1000602.1996 7 Annex A (informative) Bibliography ANSI X3.4-1986, Information systems Coded character sets 7-bit American National Standard code for information interchange (7-bit ASCII)
