1、INTERNATIONAL STANDARD ISO/IEC 13871 First edition 1995-l 2-l 5 Information technology - Telecommunications and information exchange between systems - Private telecommunications networks - Digital channel aggregation Technologies de /information - T6ltkommunications et kchange dinformation entre sys
2、tkmes - RBseaux priv& de tr%communications - Agrkgation de canal numkique Reference number ISO/IEC 13871:1995(E) ISO/IEC 13871: 1995(E) Contents page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . V 1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5、 . . . . 1 2 Normative References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 Symbols and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5 Selection of ISO/IEC 13871 or ITU-T H.244 aggregation procedures . . . . . . . . . , . . . . . . . . . . . . 3 6 Basic Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1 Modes of operation 5 6.2 Frame Structure . 6 6.2.1 Bit Ordering 7 6.2.2 Frame Alignment Word (FAW) 7 6.2.3 Frame Count (FC) . 7 6.2.4 Inform
9、ation Channel (IC) 7 6.2.5 Cyclic Redundancy Check (CRC), 8 6.2.6 Distribution of Overhead Octets 8 6.3 Overall Frame alignment . 9 6.4 Description of CRC4 procedure . 10 6.4.1 Computation of the CRC4 bits 10 6.4.1.1 Multiplication and division process . 10 6.4.1.2 Encoding procedure 10 6.4.1.3 Deco
10、ding procedure 10 6.4.2 Consequent actions . 10 6.4.2.1 Enabling and Disabling the CRC procedures . 10 6.4.2.2 Action on bit E 11 6.4.2.3 Monitoring for error performance 11 7 Description of the Information Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.1 Information Channel Frame . 11 7.1.1 Rate Multiplier and Subrate Multiplier Calculation and Operation . .15 7.2 Information Channel (IC) synchronization .19 7.3 Transmission and Recognition of an Information Channel Frame
12、. .19 8 Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8.1 Call Setup . 20 8.1.1 Initial Chan
13、nel Setup . .21 8.1.2 Additional Channel Setup . 23 0 ISO/IEC 1995 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fro
14、m the publisher. ISO/IEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii ISO/IEC ISO/IEC 13871: 1995(E) 8.1.3 Delay Equalization .25 8.1.4 Timeout Conditions . .25 8.2 Adding Bandwidth to an Existing Call 26 8.2.1 Negotiation (Calling Endpoint Initiated
15、). 26 8.2.2 Negotiation (Answering Endpoint Initiated). .26 8.2.3 Additional Channel Setup . 27 8.2.4 Timeout Conditions 28 8.3 Deleting Bandwidth from an Existing Call 28 8.3.1 Calling Endpoint Initiated. 29 8.3.2 Answering Endpoint Initiated .3O 8.3.3 Timeout Conditions 30 8.4 Collision Resolution
16、. . .30 8.5 Call Disconnection 30 8.5.1 Calling Endpoint Initiated . 30 8.5.2 Answering Endpoint Initiated .3O 8.5.3 Timeout Conditions 31 8.6 Remote Loopback . 31 8.6.1 Timeout Conditions . .32 8.7 Error Conditions 32 8.7.1 Loss of Channel (Other Than Call Setup). . 32 8.7.2 Loss of Delay Equalizat
17、ion . 33 9 Transparent Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _. 33 9.1 Non Aggregating Unit Calling Aggregating Unit .33 9.2 Aggregating Unit Calling Non Aggregating Unit . 34 Annexes A RMULT and SUBMULT Values . . . . . . . . . . . . . . . . . . . . . . . .
18、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 A. 1 Bearer Channel Rate (BCR) = 56 kbit/s . 35 A.2 Bearer Channel Rate (BCR)= 64 kbit/s 37 B Manufacturers Identifiers . . . . . . . . . . . . . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 C Phone Number Length Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 D State Machine Description of Channel Aggregation Control . . . . . . . . . . . . . . . . . . . ._. . . . . . . . . . . . . . . . . . . . .41 D.l Reference Architecture 41 D.2 State Definitions 42 D.2.1 DEQ Negotiation Control . 42 D.2.2
21、DEQ MULTIFRAME CONTROL States . .44 D.3 Messages and Events . 44 D.3.1 Information Channel Messages . 45 D.3.2 DEQ Negotiation Control to Call Control Messages . 46 D.3.3 DEQ Negotiation Control to DEQ Multiframe Control Primitives .50 D.4.Timers . 53 D.5 State Transition Diagrams .54 D.5.1 DEQ Nego
22、tiation Control . 54 D.5.2 DEQ Multiframe Control 58 D.6. SDL Diagrams 59 D.6.1 DEQ Negotiation Control . 60 D.6.2 DEQ Multiframe Control . .87 . . . 111 ISO/IEC 13871: 1995(E) OISO/IEC Foreword IS0 (the International Organization for Standardization) and IEC (the Inter- national Electrotechnical Co
23、mmission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity.
24、IS0 and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC have established a joint technical committee,
25、ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 13871 was prepared by
26、Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecommunications and information exchange between systems. Annexes A to C form an integral part of this International Standard. Annex D is for information only. iv ISO/IEC ISO/IEC 13871: 1995(E) Introduction This I
27、nternational Standard is one of a set of International Standards designed to facilitate the global interconnection of applications across both private telecommunications networks and public ISDNs. This is achieved by ensuring compatibility and interworking of services offered by the private and publ
28、ic networks. In line with the above aims, this International Standard defines a service offering flexible bandwidth allocation that provides unrestricted information transfer between special terminal adapters called Channel Aggregation Units. A Channel Aggregation Unit can provide a high bandwidth c
29、apability to an attached terminal application by combining multiple 56 kbit/s or 64 kbit/s digital communications channels that are available across public and/or private networks. It also ensures that bit sequence integrity of the aggregated bandwidth is maintained across the network(s). The number
30、 of individual communications channels aggregated may range from one up to the practical limits imposed by the Channel Aggregation Unit. The service defined in this International Standard can be used for a number of applications, including o LAN interconnection 0 image transfer o bulk file transfer
31、0 video conferencing. ITU-T Recommendation H.244 defines the means by which the appropriate choice of channel aggregation procedures may be made, in accordance with the requirements of the application being served. This choice is made from two available sets of procedures, one of which is also defin
32、ed by ITU-T Recommendation H.244, the other of which is defined in this International Standard. V INTERNATIONAL STANDARD 0 ISO/IEC ISO/IEC 13871: 1995(E) Information technology - Telecommunications and information exchange between systems - Private telecommunications networks - Digital channel aggre
33、gation 1 Scope This International Standard defines a set of procedures collectively called Digital Channel Aggregation, which are used in the provision of an aggregated bearer service. Digital channel aggregation involves a means for the combination of multiple switched or unswitched 56 kbit/s or 64
34、 kbit/s digital communications channels across one or more public and/or private networks into higher bandwidth digital bi-directional channels between Channel Aggregation Units (CAUs) serving terminal applications at network endpoints. Figure 1 below illustrates a typical channel aggregation scenar
35、io. Channels rhannelc TE = Terminal Equipment CAU = Channel Aggregation Unit = = - - w- - Note: The Figure does not show the signalling and termination features necessary to connect the CAU to the Network Figure 1 - Channel Aggregation Scenario In defining the channel aggregation procedures, this In
36、ternational Standard sets out the means used by a CAU to 0 establish the parameters to be used for the aggregated connection 0 synchronise and align multiple communications channels to maintain the bit sequence integrity of the aggregated bandwidth across the network(s) 0 optionally monitor data tra
37、nsfer throughout a call to detect failure modes 0 institute failure recovery procedures 0 optionally dynamically vary the bandwidth on demand during a call. The channel aggregation procedures above are defined at the interface between the CAU and the network in terms of the frame structure and infor
38、mation messages applied to individual communications channels. Not defined by this International Standard are 0 the call control procedures used to establish and disconnect the individual communications channels that make up the higher bandwidth connections 0 the higher level protocols or applicatio
39、ns that use the channel aggregation services 0 the frame structure on the individual communications channels at the physical interface between the CAU and the network as required for normal 56 kbit/s or 64 kbit/s bearer services as opposed to aggregated bearer services 0 the electrical characteristi
40、cs of the individual communications channels at the physical interface between the CAU and the network. 1 ISO/IEC 13871: 1995(E) OISOLIEC 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At
41、the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS
42、0 maintain registers of currently valid International Standards. ISO/IEC 11571:1994, Information technology - Telecommunications and information exchange between systems - Numbering and sub-addressing in private integrated services networks. ITU-T Recommendation G.704 (1991), Synchronous frame struc
43、tures used at primary and secondary hierarchical levels. ITU-T Recommendation H.221 (1994), Frame structure for a 64 to 1920 kbit/s channel in audiovisual teleservices. ITU-T Draft Recommendation H.244 (1995), Synchronized aggregation of ZSDN-B channels. ITU-T Recommendation H.320 (1994), Narrow-ban
44、d visual telephone systems and terminal equipment. ITU-T Recommendation I. 112 (1992), Vocabulary of terms for ZSDNs. ITU-T Recommendation T.35 (199 l), Procedure for the allocation of CCITT defined codes for non-standard facilities. 3 Definitions For the purposes of this International Standard, the
45、 following definitions apply. 3.1 Answering Endpoint: The endpoint that receives the call. 3.1 Bearer Channel: The network provided channel used to carry the data. The framing structure is overlaid on the Bearer Channel to provide the data transport and inverse multiplexing capability. Examples of B
46、earer Channels are: o BRI or PRI B-channels o Tl DSOs o Switched 56164 kbit/s connections 3.3 Bearer Channel Rate: The data rate at which the Bearer Channel is clocked. 3.4 Calling Endpoint: The endpoint that initiates the call. 3.5 Channel Aggregation Unit: Any piece of equipment adhering to this I
47、nternational Standard. Note that any reference to other forms of channel aggregation (e.g., H.244) will be stated explicitly. 3.6 CRC Encoder: The function that calculates the CRC for inclusion in the transmitting direction. 3.7 Information Message: The 16 octet message sent and received over the In
48、formation Channel in the multiframe structure or over the entire bandwidth of the Master Channel during initial parameter negotiation. This message is transmitted continuously. In this International Standard, the use of the term Information Message, when discussing receipt of a message, indicates a
49、message which has been recognized after the use of some form of detection processing (e.g., 2 out of 3 majority voting). 3.8 Master Channel: The channel used to communicate control information between each endpoint. This includes the initial parameter negotiation for call setup, channel delete, channel addition, remote loopback, call disconnection, etc. See 8.1.1 for further information. 3.9 Overall System Delay: The end-to-end transit delay (length of time it takes for the data to get from the transmitter to the receiver) including following: o D
