1、 Standard ECMA-332 December 2001 Standardizing Information and Communication Systems Corporate Telecommunication Networks - Signalling Interworking between QSIG and H.323 - Basic Services Phone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.ch . Standard
2、ECMA-332 December 2001 Standardizing Information and Communication Systems Corporate Telecommunication Networks - Signalling Interworking between QSIG and H.323 - Basic Services Phone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.ch IW Ecma-332.doc 07-01
3、-02 16,41 . Brief History This Standard is one of a series of ECMA Standards defining the interworking of services and signalling protocols deployed in corporate telecommunication networks (CNs). The series uses telecommunication concepts as developed by ITU-T and conforms to the framework of Intern
4、ational Standards on Open Systems Interconnection as defined by ISO/IEC. It has been produced under ETSI work item DTS/ECMA-00216. This particular Standard defines the signalling protocol interworking for basic services between a Private Integrated Services Network (PISN) and a packet-based private
5、telecommunications network based on the Internet Protocol (IP). It is further assumed that the protocol for the PISN part is that defined for the Q reference point (QSIG) and that the protocols for the IP-based network are based on ITU-T Recommendation H.323. This Standard is based upon the practica
6、l experience of ECMA member companies and the results of their active and continuous participation in the work of ISO/IEC JTC1, ITU-T, ETSI and other international and national standardization bodies. It represents a pragmatic and widely based consensus. This ECMA Standard is contributed to ISO/IEC
7、JTC1 under the terms of the fast-track procedure, for adoption as an ISO/IEC International Standard. This ECMA Standard has been adopted by the General Assembly of December 2001. - i - Table of contents 1 Scope 1 2 Conformance 1 3 References 1 4 Definitions 2 4.1 External definitions 2 4.2 Other def
8、initions 2 4.2.1 Gateway 2 4.2.2 IP network 2 4.2.3 Ring-back tone 2 5 Acronyms 3 6 Architecture 3 7 General requirements 4 8 Message mapping requirements 4 8.1 Message validation and handling of protocol errors 4 8.2 Call establishment from QSIG to H.323 5 8.2.1 Call establishment from QSIG to H.32
9、3 using admission procedures 5 8.2.2 Call establishment from QSIG to H.323 without admission procedures 9 8.3 Call establishment from H.323 to QSIG 12 8.3.1 Receipt of an H.225.0 SETUP message 12 8.3.2 Additional messages relating to overlap sending 13 8.3.3 Receipt of a QSIG CALL PROCEEDING message
10、 14 8.3.4 Receipt of a QSIG ALERTING message 14 8.3.5 Receipt of a QSIG CONNECT message 14 8.4 PROGRESS messages and Progress indicator information elements 14 8.4.1 Receipt of a Progress indicator information element in a QSIG message 14 8.4.2 Receipt of a Progress indicator information element in
11、an H.225.0 message 14 8.4.3 Transmission of Progress indicator information element in support of gateway-provided ring-back tone. 14 8.5 Call clearing 14 8.5.1 Call clearing initiated by QSIG 14 8.5.2 Call clearing initiated by H.323 14 9 Numbering requirements 15 9.1 Supported numbering plans and t
12、ypes of number 15 9.2 Mapping numbers from QSIG to H.323 15 9.3 Mapping numbers from H.323 to QSIG 16 9.4 Handling of presentation and screening indicators 17 - ii - 9.5 Handling of subaddresses 17 10 Security requirements 17 11 Requirements for support of basic services 17 11.1 Calls from QSIG to H
13、.323 18 11.2 Calls from H.323 to QSIG 19 12 Media channel establishment 19 13 Requirements for the support of group 3 fax in accordance with H.323 annex D 20 13.1 Start of fax transmission 20 13.2 End of fax transmission 20 14 Requirements for the support of DTMF 20 15 Requirements for the provision
14、 of ring-back tone 21 Annex A - Implementation Conformance Statement (ICS) proforma 23 Annex B - Example message sequences 39 1 Scope This Standard specifies signalling interworking between “QSIG” and “H.323” in support of basic services within a corporate telecommunication network (CN). “QSIG” is a
15、 signalling protocol that operates at the Q reference point between Private Integrated services Network eXchange (PINX) within a Private Integrated Services Network (PISN). The Q reference point is defined in ECMA-133. A PISN provides circuit-switched basic services and supplementary services to its
16、 users. QSIG is specified in other ECMA Standards, in particular ECMA-143 (call control in support of basic services). “H.323” is a set of signalling protocols for the support of voice or multimedia communication within a packet network, in particular a packet network that uses the Internet Protocol
17、 (IP) as its network layer protocol (IP network). H.323 signalling protocols operate between endpoints in an IP network, either indirectly via one or more gatekeepers, or directly. An endpoint can be a terminal or a gateway to another network. H.323 is an “umbrella” recommendation referring to vario
18、us ITU-T recommendations, in particular recommendations H.225.0 and H.245 (basic communication capabilities). This Standard specifies signalling interworking for basic services that provide a bidirectional transfer capability for speech, DTMF, facsimile and modem media between a PISN employing QSIG
19、and a private IP network employing H.323. This Standard specifies requirements for establishing user information (audio) connections between the PISN and the IP network, but protocols for transmitting audio in the IP network and for signalling in order to establish and close down audio transmission
20、in the IP network are outside the scope of this Standard. Supplementary services are outside the scope of this Standard. Interworking between QSIG and H.323 permits a call originating at a user of a PISN to terminate at a user of a private IP network, or a call originating at a user of a private IP
21、network to terminate at a user of a PISN. Interworking between a PISN employing QSIG and a public IP network employing H.323 is outside the scope of this Standard. However, the functionality specified in this Standard is in principle applicable to such a scenario when deployed in conjunction with ot
22、her relevant functionality (e.g., number translation, security functions, etc.). Although two such gateways can operate as peers on either side of an IP network (whereby the IP network provides interconnection between two PISNs), special support for this situation (e.g., tunnelling of QSIG informati
23、on through the IP network) is outside the scope of this Standard. Although two such gateways can operate as peers on either side of a PISN (whereby the PISN provides interconnection between two IP networks), special support for this situation (e.g., tunnelling of H.323 information through the PISN)
24、is outside the scope of this Standard. This Standard is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG and a private IP network employing H.323. 2 Conformance In order to conform to this Standard, a gateway shall satisfy the requirements identified in the
25、 Implementation Conformance Statement (ICS) proforma in annex A. 3 References The following standards contain provisions which, through reference in this text, constitute provisions of this Standard. All standards are subject to revision, and parties to agreements based on this Standard are encourag
26、ed to investigate the possibility of applying the most recent editions of the standards indicated below. In the case of references to ECMA Standards that are aligned with ISO/IEC International Standards, the number of the appropriate ISO/IEC International Standard is given in brackets after the ECMA
27、 reference. ECMA-133 Private Integrated Services Network (PISN) - Reference Configuration for PISN Exchanges (PINX) (International Standard ISO/IEC 11579-1) - 2 - ECMA-143 Private Integrated Services Network (PISN) - Circuit Mode Bearer Services - Inter-Exchange Signalling Procedures and Protocol (I
28、nternational Standard ISO/IEC 11572) ECMA-155 Private Integrated Services Networks - Addressing (International Standard ISO/IEC 11571) ECMA-253 Private Integrated Services Network (PISN) - Mapping Functions for the Employment of 64 kbit/s Circuit Mode Connections with 16 kbit/s Sub-Multiplexing (Int
29、ernational Standard ISO/IEC 17310) ECMA-289 Private Integrated Services Network (PISN) - Mapping Functions for the Employment of 64 kbit/s Circuit Mode Connections with 8 kbit/s Sub-Multiplexing (International Standard ISO/IEC 17311) ECMA-307 Corporate Telecommunication Networks - Signalling Interwo
30、rking between QSIG and H.323 - Generic Functional Protocol for the Support of Supplementary Services (International Standard ISO/IEC 21409) ITU-T Rec. H.225.0 version 4 Call signalling protocols and media stream packetization for packet-based multimedia communication systems (11/2000) ITU-T Rec. H.2
31、35 version 2 Security and encryption for H-Series (H.323 and other H.245-based) multimedia terminals (11/2000) ITU-T Rec. H.245 version 7 Control protocol for multimedia communication (11/2000) ITU-T Rec. H.323 version 4 Packet-based multimedia communications systems (11/2000) 4 Definitions For the
32、purposes of this Standard, the following definitions apply. 4.1 External definitions This Standard uses the following terms defined in other documents: Call (ECMA-307) Corporate telecommunication network (CN) (ECMA-307) Endpoint (ITU-T Rec. H.323) Gatekeeper (ITU-T Rec. H.323) Private Integrated Ser
33、vices Network (PISN) (ECMA-307) Private Integrated services Network eXchange (PINX) (ECMA-133) Additionally the definitions in ECMA-143 and ITU-T Recommendation H.323 apply as appropriate. 4.2 Other definitions 4.2.1 Gateway A gateway as defined in H.323 specifically for the purpose of interworking
34、with a network employing QSIG. 4.2.2 IP network A network, unless otherwise stated a CN, offering connectionless packet-mode services based on the Internet Protocol (IP) as the network layer protocol. 4.2.3 Ring-back tone An in-band tone or announcement played to the calling user during the alerting
35、 of the called user. - 3 - 5 Acronyms CN Corporate telecommunication network ICS Implementation Conformance Statement IP Internet Protocol PINX Private Integrated services Network eXchange PISN Private Integrated Services Network 6 Architecture This Standard specifies signalling protocol interworkin
36、g aspects of a gateway between a PISN employing QSIG signalling and an IP network employing H.323 signalling. The gateway appears as a PINX to other PINXs in the PISN. The gateway appears as an H.323 endpoint to other H.323 entities in the IP network, these being: other endpoints (terminals, gateway
37、s or multipoint control units) that originate calls via the gateway to the PISN and terminate calls via the gateway from the PISN; gatekeepers, including the gatekeeper with which the gateway registers and other gatekeepers involved in call routing. This environment is illustrated in figure 1. IP ne
38、twork PISNInter-PINX linkGatewayPINXEnd-pointEnd-pointGate-keepersPINXPINXFigure 1 - Environment In addition to the signalling interworking functionality specified in this Standard, it is assumed that the gateway also includes the following functionality: one or more physical interfaces on the PISN
39、side supporting one or more inter-PINX links, each link providing one or more constant bit rate channels for media information and a reliable layer 2 connection for transporting QSIG signalling messages; and one or more physical interfaces on the IP network side supporting, through layer 1 and layer
40、 2 protocols, IP as the network layer protocol and UDP and TCP as transport layer protocols, these being used for the transport of media information and H.323 signalling protocols; a means of transferring media information in each direction between the PISN and the IP network, including, as a minimu
41、m, packetization of media information sent to the IP network and de-packetization of media information received from the IP network. NOTE The gateway can be decomposed as described in 6.3.1 of H.323. In this case, the signalling interworking aspects of the gateway, as specified in this Standard, can
42、 be expected to reside in the Media Gateway Controller (MGC). The protocol model relevant to signalling interworking functionality of a gateway is shown in figure 2. - 4 - IP networklower layersUDP/TCPPISNIP networkInterworkingfunctionH.225.0RASH.225.0callcontrolH.245IPQSIGlayer 3PISN lowerlayersFig
43、ure 2 Protocol model The relevant signalling protocols on the IP network side of the gateway are: H.225.0 Registration, Admission and Status (RAS); H.225.0 call control, for the purpose of establishing and clearing down sessions between endpoints; and H.245, for the purpose of supervising resources
44、during a session. The interworking function therefore provides interworking between QSIG on the PISN side and H.225.0 RAS, H.225.0 call control and H.245 on the IP network side. 7 General requirements In order to conform to this Standard, a gateway shall support QSIG in accordance with ECMA-143 and
45、shall support H.323 in accordance with H.323 version 4 or later (including H.225.0 version 4 or later and H.245 version 7 or later). The gateway shall be able to interoperate with other H.323 entities in accordance with the provisions of H.323 version 4. The gateway shall support calls from QSIG to
46、an H.323 endpoint and calls from an H.323 endpoint to QSIG. The gateway shall be able to discover and register with a gatekeeper. The means of doing this is outside the scope of this Standard, but should be in accordance with H.323 RAS procedures. The procedures specified in this Standard for call e
47、stablishment apply after successful registration. The gateway may also be able to operate without registering with a gatekeeper. In this case the means by which the gateway maps QSIG numbers to IP addresses for routing calls from QSIG to an H.323 endpoint is outside the scope of this Standard. For o
48、peration with a gatekeeper, the gateway shall be able to employ admission and disengage procedures. The gateway may support pre-granted admission procedures. For operation with a gatekeeper, the gateway shall be able to support both direct call signalling and gatekeeper-routed call signalling. Unles
49、s pre-granted admission procedures apply, choice of call signalling method shall be in accordance with instructions from the gatekeeper at the time of admission. 8 Message mapping requirements 8.1 Message validation and handling of protocol errors The gateway shall validate received QSIG messages in accordance with the requirements of ECMA-143 and shall act in accordance with ECMA-143 on detection of a QSIG protocol error. The gateway shall validate received H.225.0 messages in accordance with the requirements of ITU-T recommendation H.323 and H.225.0 and sh
