1、BRITISH STANDARD BS ISO/IEC 9314-5:1995 Implementation of ISO/IEC 9314-5:1995 Information technology FibreDistributed Data Interface (FDDI) Part 5: Hybrid Ring Control (HRC)BS ISO/IEC9314-5:1995 This British Standard, having been prepared under the directionof the Information Systems Technology Asse
2、mbly,was published underthe authority of the Standards Board and comes into effect on 15July 1995 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference IST/6/10 Draft for comment 91/66218 DC ISBN 0 580 24376 1 Committees responsible for this BritishStandar
3、d The preparation of this British Standard was entrusted by Technical Committee IST/6, Data communications, to Technical Subcommittee IST/6/10, IEC/CLC Monitoring Subcommittee, upon which the following bodies were represented: British Telecommunications plc Digital Equipment Co. Ltd. Electrical Cont
4、ractors Association Electricity Association Institution of Electrical Engineers Nine Tiles Computer Systems Ltd. Amendments issued since publication Amd. No. Date CommentsBS ISO/IEC9314-5:1995 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iv Text
5、 of ISO/IEC 9314-5 1BS ISO/IEC9314-5:1995 ii BSI 02-2000 National foreword This British Standard reproduces verbatim ISO/IEC9314-5:1995 and implements it as the UK national standard. This British Standard is published under thedirection of the Information Systems Technology Assembly whose Technical
6、Subcommittee IST/6/10 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate t
7、hem in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsi
8、ble for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theISO/IECtitle page, pagesii toiv, pages1 to96 and a back cover. This standar
9、d has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO/IEC9314-5:1995(E) ii BSI 02-2000 Contents Page Foreword iv 1 Scope 1 2 Normative references 1 3 Definitions 2 4 Conventions and abbreviations
10、8 4.1 Conventions 8 4.2 Abbreviations 8 5 General description 9 5.1 Traffic types 10 5.2 Transmission facilities 11 5.3 Bandwidth management 12 5.4 Station structure 13 6 HRC services 17 6.1 PHY to H-MUX services 17 6.2 H-MUX to MAC services 18 6.3 H-MUX to P-MAC services 19 6.4 H-MUX to I-MAC servi
11、ces 20 6.5 H-MUX to SMT services 23 6.6 I-MAC to CS-MUX services 28 6.7 I-MAC to SMT services 30 7 Facilities 31 7.1 H-MUX symbol set 31 7.2 Cycle 31 7.3 HRC protocol parameters 34 7.4 Variables 36 7.5 Timers 38 7.6 Counters 39 7.7 Signals 39 7.8 Functions 40 8 Operation 40 8.1 Ring operation overvi
12、ew 40 8.2 Error recovery 45 8.3 Structure 47 8.4 Cycle acquisition 51 8.5 Cycle generation process 60 8.6 Cycle exchange process 76 Annex A (informative) Examples of the circuit-switch service class 79 Annex B (informative) FDDI station considerations 85 Annex C (informative) Isochronous call contro
13、l procedures 89 Annex D (informative) Isochronous channel security 93 Annex E (informative) Isochronous bandwidth management 94 Annex F (informative) Logical ranking of monitors 96 Figure 1 Structure of FDDI standards 3 Figure 2 HRC cycle structure 9 Figure 3 Hybrid mode traffic types 10 Figure 4 Ba
14、ndwidth management hierarchy 12 Figure 5 Data flow through an FDDI-II monitor station 13 Figure 6 Data flow through an FDDI-II non-monitor station 14 Figure 7 Architectural block diagram of the H-MUX 15 Figure 8 Architectural block diagram of the I-MAC 16ISO/IEC9314-5:1995(E) BSI 02-2000 iii Page Fi
15、gure 9 H-MUX cycle structure at 100 Mbps 31 Figure 10 H-MUX cycle header 32 Figure 11 Example of wideband channel interleaving 34 Figure 12 Example of wideband channel sorting 34 Figure 13 H-MUX structure 48 Figure 14 HRC receive state diagram 52 Figure 15 WBC template filter state diagram 56 Figure
16、 16 HRC cycle control state diagram 61 Figure 17 HRC cycle generate state diagram 69 Figure 18 WBC template generation state diagram 76 Figure A.1 Example of a byte interleave burst mode CS-MUX 80 Figure A.2 Example of a bit interleave burst mode CS-MUX 80 Figure A.3 Example of a bit interleave cont
17、inuous mode CS-MUX 81 Figure A.4 Example of 2048 kbps G.703/G.732 bridge and associated CS-MUX 82 Figure A.5 Example FDDI-II to G.703/G.732 protocol layers 83 Figure B.1 FDDI-II clock tolerance budget 87 Figure B.2 Sinusoidal and triangular jitter waves 87 Figure B.3 FDDI-II allowable input jitter v
18、s. network maximum jitter 88 Figure C.1 Isochronous channel reservation 90 Figure C.2 Isochronous call establishment 91 Figure C.3 Isochronous call released from destination station 92 Figure C.4 Isochronous call released from originating station 92 Figure C.5 Isochronous channel release 93ISO/IEC93
19、14-5:1995(E) iv BSI 02-2000 Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of Internatio
20、nal Standards through the technical committees established by the respective organization to deal with particular fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information tech
21、nology, ISO and IEC have established a joint technical committee ISO/IECJTC1. 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 least75% of the national bodies casting
22、a vote. International Standard ISO/IEC9314-5 was prepared by Joint Technical Committee ISO/IECJTC1, Information technology, Subcommittee SC25, Interconnection of information technology equipment. ISO/IEC 9314 consists of the following parts, under the general title Information technology Fibre Distr
23、ibuted Data Interface (FDDI): Part 1: Token Ring Physical Layer Protocol (PHY); Part 2: Token Ring Media Access Control (MAC); Part 3: Physical Layer, Medium Dependent (PMD); Part 5: Hybrid Ring Control (HRC). Annex A to Annex F of this part of ISO/IEC9314 are for information only.ISO/IEC9314-5:1995
24、(E) BSI 02-2000 1 1 Scope This part of ISO/IEC9314 specifies a hybrid ring control (HRC) protocol which provides a mode of operation in which both packet switched and isochronous data are transmitted within the same special frame structure, called a cycle. HRC is designed to operate with the existin
25、g media access control (MAC), physical layer (PHY), and physical medium dependent (PMD) layers of the FDDI protocol. The HRC is composed of the hybrid multiplexer (H-MUX) and the isochronous media access control (I-MAC) protocols. The H-MUX integrates packet and isochronous data into cycles which it
26、 transmits onto and receives from the medium using the services of the physical layer. The I-MAC provides separate transmission channels for the transfer of user isochronous data streams. The format, clocking and synchronization of cycles, and the operation and interfaces of the H-MUX and I-MAC are
27、defined by this part of ISO/IEC9314. These interfaces include the interface to the FDDI station management (SMT) protocol. The HRC is designed to support various transmission rates, from100Mbps upwards, in increments of6,144Mbps. All transmission rate dependent parameters defined in this part of ISO
28、/IEC9314 assume a transmission rate of100Mbps. Stations composed of FDDI and HRC entities are referred to as FDDI-II stations. The FDDI packet MAC (P-MAC) and the HRC components, and their architectural relationship to LLC and a circuit switching Multiplexer (CS-MUX) are illustrated inFigure 1. This
29、 figure does not imply an implementation configuration FDDI-II networks consist of FDDI-II stations. Interoperability between FDDI and FDDI-II stations on the same network is provided in HRC basic mode, which only supports packet transmission. The set of FDDI standards, ISO/IEC9314, specifies the in
30、terfaces, functions, and operations necessary to ensure interoperability between conforming FDDI implementations. This part of ISO/IEC9314 specifies a hybrid ring control protocol: HRC. Conforming implementations may employ any design technique that does not violate interoperability. 2 Normative ref
31、erences The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO/IEC9314. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO/IEC93
32、14 are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 9314-1:1989, Information processing systems Fibre Distributed Data Interface (FDDI) Part 1: T
33、oken Ring Physical Layer Protocol (PHY). ISO 9314-2:1989, Information processing systems Fibre Distributed Data Interface (FDDI) Part 2: Token Ring Media Access Control (MAC). ISO/IEC 9314-3:1990, Information processing systems Fibre Distributed Data Interface (FDDI) Part 3: Physical Layer Medium De
34、pendent (PMD). ISO/IEC 9314-7:, Information technology Fibre Distributed Data Interface (FDDI) Part 7: Physical Layer Protocol-2 (PHYS-2) 1) . ISO/IEC 9314-8:, Information technology Fibre Distributed Data Interface (FDDI) Part 8: Media Access Control-2 (MAC-2) 1) . ISO 8802-2:1994, Information tech
35、nology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements Part 2: Logical link control. 1) To be published.ISO/IEC9314-5:1995(E) 2 BSI 02-2000 3 Definitions For the purpose of this part of ISO/IEC9314, the following definitions appl
36、y: 3.1 basic mode an FDDI-II network operating in basic mode supports FDDI token ring operation only, that is, only the packet switching service is provided. The data unit transmitted on the medium in basic mode is the FDDI frame 3.2 channel the term “channel” is a synonym for “transmission channel”
37、 3.3 circuit a circuit is a bidirectional communications capability provided over a continuous isochronous channel(s) between two or more CS-MUX level entities 3.4 circuit switching circuit switching is the service that provides and manages a set of circuits 3.5 circuit switching multiplexer (CS-MUX
38、) a CS-MUX multiplexes and demultiplexes circuits onto transmission channels for transmission 3.6 connection a connection is a concatenation of circuits and other functional units set up to provide for the transfer of signals between two or more points in a telecommunications network 3.7 cycle the c
39、ycle is the HRC frame. It has a duration of1254s and nominally carries3120 symbols at100Mbps 3.8 cycle control field the cycle control field is a two symbol field in the cycle header. One symbol is for synchronization control while the other is for sequence control. These are used to indicate whethe
40、r or not cycle synchronization and sequence, respectively, are being maintained. Each of these fields may only be set by the cycle master 3.9 cycle header the cycle header begins with the preamble, which establishes the boundary of the1254s cycle. The remainder of the cycle header provides synchroni
41、zation control, sequence control, a cycle sequence field and the cycle programming template 3.10 cycle master one ranked monitor in an FDDI-II ring assumes the role of the cycle master. The ring has only one cycle master at a time. The cycle master is responsible for generating and maintaining the c
42、ycle structure and the timing of the ring. The cycle master inserts a latency adjustment buffer to adjust the ring size to be an integer multiple of1254s. The cycle master is selected by bidding among ranked monitor stations the monitor with the highest rank becomes the cycle master ISO/IEC9314-5:19
43、95(E) BSI 02-2000 3 3.11 cycle sequence cycle sequence is a scheme for indicating whether or not the correct order of cycle transmission is being maintained during normal hybrid mode operation. The sequence number of each cycle is indicated in the cycle sequence field of the cycle header. Cycle sequ
44、ence values 1-63 are used to indicate monitor ranking, and values 64-255 are used for sequencing 3.12 cycle structure the cycle structure defines the format of the cycle. The cycle is comprised of the preamble, cycle header, dedicated packet group and cyclic groups 3.13 cyclic groups the cycle struc
45、ture contains 16 wideband channels (WBCs), which are byte interleaved with each other. The interleaving scheme physically organizes the WBCs into 96 cyclic groups per cycle, at100Mbps. Each cyclic group contains one byte from each WBC. The bytes from each WBC occur in the same position in each cycli
46、c group Figure 1 Structure of FDDI standardsISO/IEC9314-5:1995(E) 4 BSI 02-2000 3.14 dedicated packet group (DPG) the dedicated packet group is the part of the cycle structure which provides a minimum packet channel bandwidth of0,768Mbps (at100Mbps) 3.15 entity an entity is an active functional agen
47、t within an (OSI) layer or sublayer, including both operational and management functions 3.16 FDDI-II FDDI-II is a term used to describe a network consisting of stations composed of FDDI and HRC entities 3.17 fibreoptics the technology whereby optical signals from light-generating transmitters are p
48、ropagated through optical fibre waveguides to light-detecting receivers 3.18 hybrid isochronous-MAC service access point (HI-SAP) HI-SAPs are the isochronous access points of the H-MUX. They are used by the I-MAC to access the WBCs 3.19 hybrid mode an FDDI-II network operating in hybrid mode imposes
49、 a cycle structure with a length of1254s. The cycle supports a variable rate packet switching service using the FDDI token ring protocol plus a time-division multiplexed circuit switching service. The bandwidth is partitioned as a dedicated packet data channel plus16 wideband channels which are dynamically allocated for packet data or isochronous use 3.20 hybrid multiplexer (H-MUX) the hybrid multiplexer is the component that directs the data flow between the
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