1、I N T E R N AT IO N A L S TA N D A R D ISO/IEC 93 14-5 First edit io n 1995-02-01 Information technology - Fibre Distributed Data Interface (FDDI) - Part 5: Hybrid Ring Control (HRC) Technologies de Iinformation - Interface de donnees distribuees sur fibre (FDDI) - Partie 5: Cornmande hybride par an
2、neau (HRC) National Standard of Canada CA N/CSA-ISO/IEC-9314-5-96 International Standard ISO/IEC 9314-5 : 1995 has been adopted, without modification, as CAN/CSA-ISO/IEC-9314-5-96, which has been approved as a National Standard of Canada by the Standards Council of Canada. April 1996 Reference numbe
3、r ISO/lEC 931 4-5:1995E) iSO/IEC 931 4-5 1995 (E) Contents Foreword . iv 1 Scope . 1 2 Normative references . 1 3 Definitions 2 4 Conventions and abbreviations 6 4.1 Conventions . 6 4.2 Abbreviations 7 5 General description 8 5 .I Traffic types 9 5.2 Transmission facilities 9 5.4 Station structure .
4、 12 5.3 Bandwidth management . 11 6 HRC services 16 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 services 21 6.5 H-MUX to SMT services . 24 6.6 I-MAC to CS-MUX services 30 6.7 I-MAC to SMT services 32 7 Facilities . 34 7.1 H-MUX symb
5、ol set . 34 7.3 HRC protocol parameters . 38 7.4 Variables 39 7.5 Timers 42 7.6 Counters . 43 7.8 Functions 44 7.2 Cycle 34 7.7 Signals 43 8 Operation . 44 8.1 Ring operation overview . 44 8.2 Error recovery . 50 8.3 Structure . 53 8.5 Cycle generation process . 67 8.6 Cycle exchange process 84 8.4
6、Cycle acquisition 57 0 ISOIIEC 1995 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 microfilm. without permission in writing from the publisher . International Organization for Standardi
7、zation Case postale 56 CH-1211 Geneve 20 Switzerland ii ISO/IEC 9314-5 1995 (E) Annexes A . Examples of the circuit-switch service class . 86 B . FDDl station considerations 94 C - Isochronous call control procedures . 99 D - Isochronous channel security . 104 E - Isochronous bandwidth management .
8、106 F - Logical ranking of monitors . 108 Figures Figure 1 . Structure of FDDl standards 3 Figure 3 - Hybrid mode traffic types . 9 Figure 4 - Bandwidth management hierarchy 11 Figure 5 - Data flow through an FDDI-II monitor station . 13 Figure 8 - Architectural block diagram of the I-MAC . 16 Figur
9、e 10 - H-MUX cycle header 35 Figure 2 - HRC cycle structure . 8 Figure 6 - Data flow through an FDDI-II non-monitor station . 14 Figure 7 - Architectural block diagram of the H-MUX . 14 Figure 9 - H-MUX cycle structure at 100 Mbps 34 Figure 11 - Example of wideband channel interleaving 37 Figure 12
10、- Example of wideband channel sorting . 37 Figure 13 - H-MUX structure 54 Figure 14 - HRC receive state diagram 58 Figure 15 - WBC template filter state diagram . 62 Figure 16 - HRC cycle control state diagram . 68 Figure 17 - HRC cycle generate state diagram 76 Figure 18 - WBC template generation s
11、tate diagram . 83 Figure A.1 - Example of a byte interleave burst mode CS-MUX 87 Figure A2 - Example of a bit interleave burst mode CS-MUX . 88 Figure A.3 - Example of a bit interleave continuous mode CS-MUX . 88 Figure A.4 - Example of 2048 kbps G.703/G.732 bridge and associated CS-MUX . 90 Figure
12、A.5 - Example FDDI-II to G.703/G.732 protocol layers . 91 Figure B.1 - FDDI-II clock tolerance budget . 96 Figure B.2 - Sinusoidal and triangular jitter waves . 96 Figure B.3 - FDDI-II allowable input jitter vs . network maximum jitter 97 Figure C.1 - Isochronous channel reservation . Figure C.2 - I
13、sochronous call establishment Figure C.3 - Isochronous call released from destination station . Figure C.4 - Isochronous call released from originating station . Figure C.5 - Isochronous channel release 00 01 02 02 03 . 111 ISO/IEC 9314-5 1995 (E) Foreword IS0 (the International Organization for Sta
14、ndardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or I EC participate in the development of International Standards through the technical committees established by the respective or
15、ganization to deal with particular 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 ISO/IEC JTC 1.
16、 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 931 4-5 was prepared by Joint Technic
17、al Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 2 5, In terconn e ction of in forma fion tech n olugy e g uipm en t. ISO/IEC 9314 consists of the following parts, under the general title lnforma fion technology - Fibre Distributed Data Interface (FDDI): - Part I: Token Ring Physi
18、cal Layer Protocol (PHY) - Part 2: Token Ring Media Access Control (MAC) - Part 3: Physical Layer, Medium Dependent (PMD) - Part 5: Hybrid Ring Control (HRC) Annexes A to F of this part of ISO/IEC 931 4 are for information only. iv INTERNATIONAL STANDARD 0 ISOAEC ISO/IEC 931 4-5 1995 (E) nformation
19、technology - Fibre Distributed Data nterface (FDDI) - Part 5: Hybrid Ring Control (HRC) 1 Scope This part of ISOAEC 9314 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
20、structure, called a cycle. HRC is designed to operate with the existing media access control (MAC), physical layer (PHY), and physical medium dependent (PMD) layers of the FDDl protocol. The HRC is composed of the hybrid multiplexer (H-MUX) and the isochronous media access control (1- MAC) protocols
21、. The H-MUX integrates packet and isochronous data into cycles which it 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
22、of cycles, and the operation and interfaces of the H-MUX and I-MAC are defined by this part of ISO/IEC 9314. These interfaces include the interface to the FDDl station management (SMT) protocol. The HRC is designed to support various transmission rates, from 100 Mbps upwards, in increments of 6,144
23、Mbps. All transmission rate dependent parameters defined in this part of ISOAEC 931 4 assume a transmission rate of 100 Mbps. Stations composed of FDDl and HRC entities are referred to as FDD1-I1 stations. The FDDl packet MAC (P-MAC) and the HRC components, and their architectural relationship to LL
24、C and a circuit switching Multiplexer (CS-MUX) are illustrated in figure 1 - This figure does not imply an implementation configuration FDDI-II networks consist of FDDI-II stations. Interoperability between FDDl and FDDI-I stations on the same network is provided in HRC basic mode, which only suppor
25、ts packet transmission. The set of FDDl standards, ISO/IEC 931 4, specifies the interfaces, functions, and operations necessary to ensure interoperability between conforming FDDl implementations. This part of ISOAEC 931 4 specifies a hybrid ring control protocol: HRC. Conforming implementations may
26、employ any design technique that does not violate interoperability. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISOAEC 9314. At the time of publication, the editions indicated were valid. All standards
27、 are subject to revision, and parties to agreements based on this part of ISOAEC 9314 are encouraged to 1 ISOAEC 931 4-5 1995 (E) 0 ISOAEC investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 maintain registers of currently valid Inte
28、rnational Standards. IS0 931 4-1 :I 989, Information processing systems - Fibre Distributed Data lnterface (FDDl) - Part I: Token Ring Physical Layer Protocol (PHY). IS0 931 4-2: 1 989, Information processing systems - Fibre Distributed Data Interface (FDDI) - Part 2: Token Ring Media Access Control
29、 (MAC). ISO/I EC 931 4-3:f 990, Information processing systems - Fibre Distributed Data Interface (FDDI) - Part 3: Physical Layer Medium Dependent (PMD. ISO/I EC 931 4-7:-, information technology - Fibre Distributed Data interface (FDDI) - Part 7: Physical Layer Protocol-2 (PHYS-2). ISOAEC 931 4-8:-
30、 9 Information technology - Fibre Distributed Data lntetface (FDDI) - Part 8: Media Access Control-2 (MAC-2). IS0 8802-2: 1 994, Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Pad 2: Logical link c
31、ontrol. 3 Definitions For the purpose of this part of ISOAEC 931 4, the following definitions apply: 3.1 basic mode: An FDDI-II network operating in basic mode supports FDDI token ring operation only, that is, only the packet switching sewice is provided. The data unit transmitted on the medium in b
32、asic mode is the FDDI frame. 3.2 channel: The term channel is a synonym for transmission channel. 3.3 circuit: A circuit is a bidirectional communications capability provided over a continuous 3.4 circuit switching: Circuit switching is the service that provides and manages a set of circuits. 3.5 ci
33、rcuit switching multiplexer (CS-MUX): 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 tele
34、communications network. 3.7 cycle: The cycle is the HRC frame. It has a duration of 125 ps and nominally carries 3 120 symbols at 100 Mbps. 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 seq
35、uence control. These are used to indicate whether 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 the 125 ps cycle.
36、The remainder of the cycle header provides synchronization 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 mast
37、er is responsible for generating and maintaining the cycle 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 of f25 ps. The cycle master is selected by bidding among ranked monitor stations - the monitor with
38、the highest rank becomes the cycle master. isochronous channel(s) between two or more CS-MUX level entities. - To be published. 2 0 ISO/IEC ISO/I EC 931 4-5 1995 (E) Logical Link Control (LLC) Data Link Layer Physical Layer - Circuit Switching Mu I ti pl exe r( s) (CS-MUX) Management (SMT) 0 - Physi
39、cal Layer Protocol (PHY) 0 * * Physical Layer MediurnDependent (PMD) 0 * 0 MAC-2 with HRC; MAC or MAC-2 otherwise. 0 PHY-2 with HRC; PHY or PHY-2 otherwise. 0 PMD, SMF-PMD, TP-PMD or LCF-PMD. SMT-2 with HRC; SMT or SMT-2 otherwise. Figure 1 - Structure of FDDl standards 3.1 1 cycle sequence: Cycle s
40、equence 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 sequence values 1-63 are used to indicate monitor r
41、anking, and values 64-255 are used for sequencing . preamble, cycle header, dedicated packet group and cyclic groups. interleaved with each other. The interleaving scheme physically organizes the WBCs into 96 cyclic groups per cycle, at 100 Mbps. Each cyclic group contains one byte from each WBC. Th
42、e bytes from each WBC occur in the same position in each cyclic group. 3.14 dedicated packet group (DPG): The dedicated packet group is the part of the cycle structure which provides a minimum packet channel bandwidth of 0,768 Mbps (at 100 Mbps). 3.15 entity: An entity is an active functional agent
43、within an (OSI) layer or sublayer, including both operational and management functions. 3.12 cycle structure: The cycle structure defines the format of the cycle. The cycle is comprised of the 3.13 cyclic groups: The cycle structure contains 16 wideband channels (WBCs), which are byte 3 ISO/IEC 931
44、4-5 1 995 (E) 0 ISOAEC 3.16 FDDI-II: FDDI-II is a term used to describe a network consisting of stations composed of FDDI and HRC entiities. 3.17 fibreoptics: The technology whereby optical signals from light-generating transmitters are 3.18 hybrid isochronous-MAC service access point (HI-SAP): HI-S
45、APS are the isochronous access 3.19 hybrid mode: An FDDI-II network operating in hybrid mode imposes a cycle structure with a propagated through optical fibre waveguides to light-detecting receivers. points of the H-MUX. They are used by the I-MAC to access the WBCs. length of 125 ps. The cycle supp
46、orts a variable rate packet switching service using the FDDl token ring protocol plus a time-division multiplexed circuit switching service. The bandwidth is partitioned as a dedicated packet data channel plus 16 wideband channels which are dynamically allocated for packet data or isochronous use. 3
47、.20 hybrid multiplexer (H-MUX): The hybrid multiplexer is the component that directs the data flow between the packet and isochronous media access control sublayer and the physical Layer. 3.21 hybrid packet-MAC service access point (HP-SAP): The HP-SAP is the access point of the H- MUX. It is used b
48、y the P-MAC to access the packet data channel. One HP-SAP exists and makes available a variable data rate between 0,768 Mbps and 99,072 Mbps, dependent on the partitioning of WBCs between circuit switching and packet switching. integrated packet and isochronous switching. It consists of the hybrid m
49、ultiplexer and the isochronous media access control. are divided into one HP-SAP and up to 16 HI-SAPS. signal such that the time intervals between consecutive significant instants either have the same duration or durations that are integral multiples of the shortest duration. 3.25 isochronous MAC service access point (I-SAP): I-SAPS are the access points of the I-MAC. They are used by the CS-MUX to access isochronous transmission channels. One and only one isochronous MAC service access po
