1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-1000113.2015 Signaling System No. 7 (SS7) Integrated Services Digital Network (ISDN) User Part As a leading technology and solutions development organization, the Alliance for Telecommunications Industry Solutions (ATIS) brings together the top
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5、tional Telecommunication Union (ITU), as well as a member of the Inter-American Telecommunication Commission (CITEL). For more information, visit www.atis.org. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensu
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10、f this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time.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 ma
11、y receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer ATIS-1000113.2015 Chapter 2, General Function of Messages and Signals; ATIS-1000113.2015 Chapter 3, Formats and Codes; ATIS-1000113.2015 Chapter 4, Signaling Procedure
12、s; ATIS-1000113.2015 Chapter 5, Performance Objectives in the ISDN Application; ATIS-1000113.2015 Chapter 6, State Transition Diagrams; and ATIS-1000113.2015 Chapter 7, Application Transport Mechanism. The overall and detailed organization of individual chapters of this standard parallels that used
13、in the equivalent ITUT recommendations. Chapters 14 correspond to Q.761Q.764. Chapter 5 corresponds to Q.766. Chapter 6 contains material previously in Chapter 4. Chapter 7 corresponds to Q.765. This standard is intended for use in conjunction with ATIS-1000110, Signaling System No. 7 (SS7)General I
14、nformation. There are thirteen annexes in this standard. Chapter 1 contains one informative annex. Chapter 3 contains one normative and three informative annexes. Chapter 4 contains five informative annexes. Chapter 7 contains one normative annex and two informative annexes. Information contained in
15、 a normative annex forms an integral part of this standard. Information contained in an informative annex is not considered part of this standard, but is rather auxiliary to the standard. Similarly footnotes are not part of this standard. In case of any conflict between the text and the Specificatio
16、n and Description Language diagrams, the text shall have precedence. Suggestions for improvement of this standard will be welcome. They should be sent to the Alliance for Telecommunications Industry Solutions, 1200 G Street, NW, Suite 500, Washington, DC 20005. This standard was processed and approv
17、ed for submittal to ANSI by the Accredited Standards Committee Packet Technologies and Systems Committee (PTSC). Committee approval of this standard does not necessarily imply that all committee members voted for its approval. At the time it approved this standard, the PTSC had the following members
18、: ii At the time of consensus on this document, PTSC, which was responsible for its development, had the following leadership: M. Dolly, PTSC Chair (AT The Generic Name describes an action by X; The Specific Name indicates the purpose of the primitive, i.e., whether it conveys a request for service,
19、 an indication that service-related information has been received, a response to a service request, or a confirmation that the requested service has been performed, and The Parameters contain the elements of supporting information transferred by the primitive. 6The use of 64 kbit/s restricted is exp
20、ected to exist during a period of transition to 64 kbit/s unrestricted. ATIS-1000113.2015 Chapter 1 4 3.2 Description of Primitives The following paragraphs describe the primitives used across the ISDN User Part - Message Transfer Part interface. The primitives together with the parameters carried b
21、y each primitive are also shown in Table 5.1 - ATIS-1000113.2015 Chapter 1. 3.2.1 Transfer The MTP-TRANSFER primitive is used either by the ISDN User Part to access the Signaling Message Handling function of the Message Transfer Part or by the latter to deliver signaling message information to the I
22、SDN User Part. 3.2.2 Pause The MTP-PAUSE primitive is sent by the Message Transfer Part to indicate its inability to transfer messages to the destination specified as a parameter. The ISDN User Part should stop sending signaling traffic while it waits for the MTP-RESUME primitive. 3.2.3 Resume The M
23、TP-RESUME primitive is sent by the Message Transfer Part to indicate its ability to resume unrestricted transfer of messages to the destination specified as a parameter. 3.2.4 Status The MTP-STATUS primitive is sent by the Message Transfer Part to indicate the signaling route to a specific destinati
24、on is congested or the ISDN User Part at the destination is unavailable. Unavailability causes can be unequipped, inaccessible, or unknown. The affected destination and the congestion indication are carried as parameters (see Table 5.1 ATIS-1000113.2015 Chapter 1) in the primitive. 4 End-to-End Sign
25、aling 4.1 General End-to-end signaling is defined as the capability to transfer signaling information directly between the end points of a built up circuit switched connection or between signaling points that are not interconnected by a circuit switched connection. End-to-end signaling is used typic
26、ally between call originating and terminating local exchanges, to request or to respond to requests for additional call related information, to invoke a supplementary service or to transfer user-to-user information transparently through the network. End-to-end signaling procedures are described in A
27、TIS-1000113.2015 Chapter 4. Two methods are available (see Figure 5.1 ATIS-1000113.2015 Chapter 1) as described in Clause 4.2 and Clause 4.3. ATIS-1000113.2015 Chapter 1 5 4.2 SCCP Method of End-to-End Signaling The means for connection-oriented or connectionless transport of end- to-end signaling i
28、nformation is provided by the services of the SCCP and the MTP of Signaling System No.7 as defined in ATIS-1000112 and ATIS-1000111, respectively. (The use of connection-oriented SCCP transport of end-to-end signaling information is for further study.) 4.3 Pass-along Method of End-to-End Signaling A
29、n alternative method for transporting end-to-end signaling information, called pass-along, is provided within the ISDN User Part, and does not require the services of the SCCP. This method may be used between two exchanges when the information to be transferred relates to an existing call for which
30、a physical connection between the same two exchanges has been established. The information transfer in this case occurs over the same signaling path as that used to set up the call and establish the physical connection. 5 Future Enhancements Requirements for additional protocol capabilities, such as
31、 the ability to support new supplementary services and network capabilities, will result from time to time in the need to add to or modify existing protocol elements and thus to create a new protocol version. In order to ensure adequate service continuity, the insertion of a new protocol version int
32、o one part of a network should be transparent to the remainder of the network. Compatible interworking between protocol versions is optimized by adhering to the following guidelines when specifying a new version: (a) Existing protocol elements (i.e., procedures, messages, parameters, and codes) shou
33、ld not be changed unless a protocol error needs to be corrected or it becomes necessary to change the operation of the service or network capability that is being supported by the protocol. (b) The semantics of a message, a parameter, or of a field within a parameter should not be changed. (c) Estab
34、lished rules for the formatting and encoding of messages should not be modified. (d) The addition of parameters to the mandatory part of an existing message should not be allowed. If needed, a new message should be defined containing the desired set of existing and new mandatory parameters. (e) A pa
35、rameter may be added to an existing message as long as it is allocated to the optional part of the message. (f) The addition of new octets to an existing mandatory fixed length parameter should be avoided. If needed, a new optional parameter should be defined containing the desired set of existing a
36、nd new information fields. (g) The sequence of fields in an existing variable length parameter should remain unchanged. New fields may be added at the end of the existing sequence of parameter fields. If a change in the sequence of parameter fields is required, a new parameter should be defined. (h)
37、 The all zeros code point should be used exclusively to indicate an unallocated (spare) or insignificant value of a parameter field. This avoids an all zeros code, sent by one protocol version as a spare value, to be interpreted as a significant value in another version. (i) The compatibility mechan
38、ism described in 5.1 applies to post-1995 versions of ATIS-1000113.2015 (formerly T1.113). ATIS-1000113.2015 Chapter 1 6 Rules (a) to (h) also apply, and additional principles, which allow this and future versions of the ANSI ISDN-UP to directly interwork with each other, maintaining protocol and se
39、rvice compatibility and including end-to-end transparency, are described in clause 5.2 below. Figure 5.1 - End-to-End Signaling Methods Chapter 1 ATIS-1000113.2015 Chapter 1 7 Table 5.1 - Description of Primitives Chapter 1 Primitives Parameters Generic Name Specific Name MTP-TRANSFER Request Indica
40、tion OPC DPC SLS SIO Signaling Info. MTP-PAUSE Indication Affected DPC MTP-RESUME Indication Affected DPC MTP-STATUS Indication Affected DPC Cause (Note) NOTE - The cause parameter can assume four values: (1) Signaling network congestion level; (2) User part unavailability - unequipped remote user;
41、(3) User part unavailability - inaccessible remote user; and (4) User part unavailability - unknown. 5.1 Version Compatibility From T1.113-2000 onwards, compatibility between the 2000 and future versions will be guaranteed, in the sense that any two versions can be interconnected directly with each
42、other, and the following requirements are fulfilled: (1) Protocol compatibility Calls between any two ISDN-UPs do not fail for the reason of “not satisfying“ protocol requirements. (2) Service and functional compatibility This requirement may be considered as compatibility typically between originat
43、ing and destination exchanges. Services and functions available at these exchanges, but possibly not yet supported in the intermediate exchanges, are supported, provided they require only transparency of the intermediate exchanges. If this is not the case, a controlled call rejection or service reje
44、ction is required. Signaling for a facility completely provided between the originating and destination exchanges could utilize one of the end-to-end methods (see Clause 3 in ATIS-1000113.2015 Chapter 4), i.e., such facilities do not have to be supported by transit exchanges. (3) Resource control an
45、d management compatibility For these functions occurring only link-by-link (e.g., maintenance messages), at least a backward notification (such as an acknowledge message) is needed, if correct handling is not possible. The compatibility mechanism is common for all ISDN-UPs from the T1.113-2000 versi
46、on onwards. It is based on forward compatibility information associated with new signaling information. The compatibility method eases the network operation, e.g., for the typical case of an ISDN-UP mismatch during network upgrading, to interconnect two networks on a different functional levels, for
47、 networks using a different subset of the same ISDN-UP. All messages and parameters contained in the T1.113-2000 version shall be recognized by all exchanges. This does not impose a requirement that the related functions are implemented, but the function shall be rejected correctly (where applicable
48、). All future new messages and parameters are subject to the rules of the compatibility mechanism (see clauses 5.2.1 and 5.2.2). ATIS-1000113.2015 Chapter 1 8 5.2 Additional Coding Guidelines for Compatibility of ISDN User Parts The following clauses detail guidelines that are mandatory. 5.2.1 Messa
49、ges All new messages use only parameters coded according to coding rules for the parameters of the optional part of ISDN-UP messages, since an exchange that does not recognize a message cannot know the length of mandatory parameters it does not recognize. The new messages always contain a Message Compatibility Information parameter. 5.2.2 Parameters As a general principle, mixing information for different application associations (requiring different functional entity actions) in a new ISUP parameter should be avoided so that