ITU-T SERIES Q SUPP 26-1999 Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No 2 (DSS2) and Signalling System No 7 (B-ISUP) - Support wit.pdf

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1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Series Q Supplement 26 (1 211 999) SERIES Q: SWITCHING AND SIGNALLING Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. 2 (DSS2) and Signalling System No. 7 (B-

2、ISUP) - Support of Services over IP-based networks ITU-T Q-series Recommendations - Supplement 26 (Formerly CCITT Recommendations) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICA

3、TIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM R1 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No.

4、1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1-Q.3 Q.4-Q.59 Q.60-Q.99 Q.100-Q.119 4.120-4

5、.249 4.250-4.309 Q.31O-Q.399 Q .40O-Q.499 Q.50O-Q.599 Q .600-Q .699 Q .70O-Q. 849 Q.850-Q.999 Q. 1000-Q.1099 Q.1100-Q. 1 199 Q.1200-4.1699 Q. 1700-4.1799 Q.2000-Q.2999 For further details, please refer to the list of ITU-T Recommendations. STD.1TU-T RECMN SERIES Q SUPP 2b-ENGL 1979 W lldb2591 Obdb52

6、7 493 Supplement 26 to ITU-T Q-series Recommendations Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. 2 (DSS2) and Signalling System No. 7 (B-ISUP) - Support of Services over IP-based networks Summary This Supplement to the Q-series Recommendations p

7、rovides guideline information to support session-related ATM Connections over the Broadband Public Network. This Supplement also describes enhancements made to B-ISDN signalling protocols on the UNI and the NNI to support services over IP-based networks. Source Supplement 26 to ITU-T Q-series Recomm

8、endations was prepared by ITU-T Study Group 11 (1997-2000) and approved under the WTSC Resolution 5 procedure on 3 December 1999. Q series - Supplement 26 (12/1999) 1 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications.

9、 The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Sta

10、ndardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC Resolution 1. In some areas of informa

11、tion technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. I

12、NTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, w

13、hether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementors are cautione

14、d that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microf

15、ilm, without permission in writing from the ITU. 11 Q series - Supplement 26 (12/1999) STD 9 ITU-T RECMN SERIES Q 1 2 3 4 5 5.1 5.2 SUPP 2b-ENG: 1999 ObEb529 bLb CONTENTS Page Scope . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Definitions . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . .

17、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sessi

18、on-related ATM Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long-lived Session Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . QoS-sensitive Session Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q series - Supplement 26 (12/1999) 1 2

20、2 2 3 4 . 111 STD=ITU-T RECMN SERIES d SUPP 2b-ENGL 1777 E Li8b2571 ObBb530 338 Supplement 26 to ITU-T Q-series Recommendations Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. 2 (DSSZ) and Signalling System No. 7 (B-ISUP) - Support of Services over I

21、P-based networks 1 Scope This Supplement defines DSS2 and B-ISUP capabilities to transport internet related information across the B-ISDN. This allows a private network, based on IP technology (e.g. IP routers), supporting the Internet applications by using signalling protocols defined in the IETF t

22、o generate and pass control information transparently through a public network. Figure 1-1 identifies an ATM transport architecture using DSS2 and B-ISUP to transport the such information across the B-ISDN. iP Router ATM Switch ATM Switch iP Router DSS2 B-ISUP DSSZ UNI “I UNI I 1 I T11 il 1290-01 Fi

23、gure 1-1 - Reference model 2 Refer ences The following Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Supplement. At the time of publication, the editions indicated were valid. All supplements and other references are subj

24、ect to revision; all users of this Supplement are therefore encouraged to investigate the possibility of applying the most recent edition of the supplements and other references listed below. A list of the currently valid ITU-T Recommendations and supplements is regularly published. ITU-T Recommenda

25、tion Q.2763 (1995), Signalling System No. 7 B-ISDN user part (B-ISUP) - Formats and codes. ITU-T Recommendation 4.2730 (1999), Signalling System No. 7 B-ISDN User Part (B-ISUP) - Supplementary services. ITU-T Recommendation 4.2726.4 (2000), Extensions to the B-ISDN User Part - Application gen era te

26、d iden tiJiers. ITU-T Recommendation 4.2941 .I (1997), Digital subscriber Signalling System No. 2 - Generic identifier transport. ITU-T Recommendation 4.2957.1 (1993, Stage 3 description for additional information transfer supplementary services using B-ISDN digital subscriber signalling System No.

27、2 (DSS2) -Basic call - User-to-User Signalling (UUS). IETF WC 2327 (1998) SDP, Session Description Protocol. ITU-T Recommendation 4.2941.2 (1999), Digital subscriber Signalling System No. 2 (DSS2): Generic identijer transport extensions. Q series - Supplement 26 (12/1999) 1 81 ITU-T Recommendation Q

28、.2957.VAmd. 1 (1 999), Stage 3 description for additional information transfer supplementary services using B-ISDN Digital Subscriber Signalling System No. 2 (DSS2) -Basic Call. 3 Definitions This Supplement defines the following term: 3.1 session: A multimedia session is a set of multimedia senders

29、 and receivers and the data streams flowing from senders to receivers. A multimedia conference is an example of a multimedia session. (RFC 2327 6). 4 Abbreviations This Supplement uses the following abbreviations: ATM Asynchronous Transfer Mode B-HLI Broadband High Layer Information B-ISDN B-ISUP B-

30、LLI Broadband Low Layer Information DSS2 GIT Generic Identifier Transport IE Information Element IETF Internet Engineering Task Force IP Internet Protocol “I Network Node Interface QOS Quality of Service RSVP Resource Reservation Protocol ST2+ UNI User Network Interface UUI User-User Information vc

31、Virtual Channel VP Virtual Path Broadband Integrated Services Digital Network Broadband Integrated Services Digital Network User Part Digital Subscriber Signalling System No. 2 Internet Stream Protocol Version 2+ 5 Session-related ATM Connection With the development of new multimedia applications on

32、 the current Internet, the demands for multimedia support are increasing in IP-based networks, which currently support only best effort communications. In particular, demands to support QoS guaranteed communications are increasing with the development of voice, audio, and video communications applic

33、ations. The major features of B-ISDN are high speed, logical multiplexing with the VPNC, and flexible QoS management per VC, so it is quite natural to use these distinctive functions of B-ISDN to implement a multimedia support mechanism for the benefit of IP-based networks. The flexible QoS manageme

34、nt and logical multiplexing functions in B-ISDN provide the QoS guaranteed 2 Q series - Supplement 26 (12/1999) STD.ITU-T RECMN SERIES Q SUPP 2b-ENGL 1999 D irBb2591 Obb532 100 = ws communications for the Internet. Furthermore, when a long-lived session is supported by a particular VC, efficient pac

35、ket forwarding may be possible using the high speed and logical multiplexing of This clause clarifies B-ISDN signalling functions that are required when a session is supported by the VC, using advanced B-ISDN signalling support of the Internet Protocol. B-ISDN. ws 5.1 Long-lived Session Signalling A

36、n example of a scenario for establishing a VC for a long-lived session is shown in Figure 5-1. ws ATM Switch ATM Switch IP Router Default VC E Router ws UNI / “I / UNI ws I II II II II II II I iP Router Default VC IP Router ws a) New session initially forwarded over a default VC b) New VC is set up

37、for the long-lived session c) Transfer of I the long-lived session to a new VC Figure 5-1 - Example of a scenario for establishing a VC for a long-lived session Initially, the session may be multiplexed into a default VC connecting the routers. If the router detects that it is a long-lived session,

38、it may set up a new VC for this specific session. Once the new VC is established successfully, the long-lived session may be transferred to the new VC. The mechanisms by which the router detects a long-lived session and moves it to the new VC are In this procedure involving an ATM VC Set-up, the B-I

39、SDN signalling entity in the called side router must detect that the incoming call corresponds to a session of the Internet Protocol and noti that fact to the IP layer entity. Based on this information, the IP layer entity moves the session to the new VC. I implementation specific and may depend on

40、the network configuration. Q series - Supplement 26 (12/1999) 3 Therefore, to implement this signalling procedure, the B-ISDN signalling must include a session identifier as an information element. The Broadband Low Layer Information (B-LLI), Broadband High Layer Information (B-HLI), User-User Infor

41、mation (UUI), and Generic Identifier Transport (GIT) Information elements are all capable of transferring this information. Considering the original purposes of these information elements, the most appropriate one to use is the Generic Identifier Transport information element. Recommendations 4.2941

42、.1 4 and Q.2941.2 7 document this specific use of GIT. The Application generated Identifier parameter, defined in Recommendation Q.2726.4 3, would be used at the NNI to identiQ the session. 5.2 QoS-sensitive Session Signalling An alternative class of session is known as a “QoS-sensitive Session“. Th

43、e major difference between QoS-sensitive session signalling and long-lived session signalling is that call set-up is not initiated by the detection of a long-lived session, but is explicitly initiated by the Set-up protocol, such as ST2+ or RSVP. To implement QoS-sensitive session signalling using A

44、TM, the ATM network between the routers must forward not only the session identifier but also the set-up protocol. There are two schemes for forwarding the set-up protocol. One is to multiplex the protocol into a default VC connecting the routers, or to forward the protocol through a particular VC.

45、In this case, the QoS-sensitive session and the ATM VC are established sequentially. The second scheme is to forward the setup protocol as an information element in the B-ISDN signalling. In this case, the QoS-sensitive session and the ATM VC are established simultaneously. The latter scheme has the

46、 following advantages compared with the former one: a) Ease of implementation Admission control is simplified, because admission control for the Ip and ATM layers can be done simultaneously. Watchdog timer processing is simplified, because there is no need to watch the IP layer establishment and ATM

47、 layer establishment sequentially. Potential use of negotiation in VC establishment However, the latter scheme, at least, cannot support a case where a PVC is used to support a QoS-sensitive session. Therefore, both procedures should be taken into account. An example of a message sequence that simul

48、taneously establishes a QoS-sensitive session and an ATM VC is shown in Figure 5-2. b) 4 Q series - Supplement 26 (12/1999) STD-ITUm-T RECMN SERIES Q SUPP 2b-ENGL 1999 = qbb2591 Obab539 TA3 IP Router / UNI ws ATM Switch ATM Switch ws CALLPROC N-CONNECT - IAM - b SETUP N-CONNECT-ACK +-I -4 SETUP CONN

49、-ACK N-CONNECT - N-CONNECT-ACK T1111131061 Figure 5-2 - Example procedure for simultaneous QoS-sensitive session and ATM VC establishment Alternative session control protocols are currently being proposed in the IETF for the set-up protocol and new Set-up protocols are likely to be developed in the near future. Therefore, to generalize the discussion, the procedure for the Set-up protocol in this example is a general connection Set-up procedure using confirmed service. In supporting a receiver initiated case, procedures other than the sequential Set-u