1、BRITISH STANDARD BS ISO/IEC 9314-8:1998 Information technology Fibre Distributed Data Interface (FDDI) Part 8: Media Access Control-2 (MAC-2) ICS 35.100.10BSISO/IEC 9314-8:1998 This British Standard, having been prepared under the direction of the DISC Board, was published under the authority of the
2、 Standards Committee and comes into effect on 15 December 1998 BSI 05-1999 ISBN 0 580 28401 8 National foreword This British Standard reproduces verbatim ISO/IEC 9314-8:1998 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee IS
3、T/39, Interconnection of IT equipment, cabling; microprocessors, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monito
4、r related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this docume
5、nt may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of Bri
6、tish Standards are responsible 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, pages i and ii, the ISO/IEC title page, pages ii to vi, pages 1 t
7、o 78, an inside back cover and aback cover. This standard 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. Amendments issued since publication Amd. No. Date CommentsBS ISO/IEC9314-8:1998 BSI 05-19
8、99 i Contents Page National foreword Inside front cover Foreword v Text of ISO/IEC 9314-8 1ii blankBS ISO/IEC9314-8:1998 ii BSI 05-1999 Contents Page Foreword v Introduction 1 1 Scope 1 2 Normative references 3 3 Definitions 4 4 Conventions and abbreviations 7 4.1 Conventions 7 4.1.1 Addressing 7 4.
9、1.2 Timing values and timers 8 4.2 Abbreviations 8 5 General description 10 6 Services 11 6.1 MAC-to-LLC services 11 6.1.1 MA_UNITDATA.request 12 6.1.2 MA_UNITDATA.indication 13 6.1.3 MA_UNITDATA_STATUS.indication 14 6.1.4 MA_TOKEN.request 15 6.2 MAC-to-PHY services 16 6.2.1 PH_UNITDATA.request 16 6
10、.2.2 PH_UNITDATA.indication 16 6.2.3 PH_INVALID.indication 17 6.3 MAC-to-H-MUX Services 17 6.3.1 HM_MODE.indication 17 6.3.2 HP_UNITDATA.request 18 6.3.3 HP_UNITDATA.indication 18 6.3.4 HP_INVALID.indication 18 6.3.5 HP_MODE.request 19 6.4 MAC-to-SMT services 19 6.4.1 SM_MA_INITIALIZE_PROTOCOL.reque
11、st 20 6.4.2 SM_MA_CONTROL.request 21 6.4.3 SM_MA_STATUS.indication 23 6.4.4 SM_MA_UNITDATA.request 24 6.4.5 SM_MA_UNITDATA.indication 25 6.4.6 SM_MA_UNITDATA_STATUS.indication 26 6.4.7 SM_MA_TOKEN.request 26 7 Facilities 27 7.1 Symbol set 27 7.1.1 Line state symbols 27 7.1.2 Control symbols 28 7.1.3
12、 Data Quartets(0-F) 28 7.1.4 Violation symbol(V) 28 7.2 Protocol Data Units 29 7.2.1 Token 29 7.2.2 Frame 29 7.3 Fields 30 7.3.1 Preamble (PA) 30 7.3.2 Starting Delimiter (SD) 30 7.3.3 Frame Control (FC) 30 7.3.4 Destination and source addresses 32 7.3.5 Routing Information (RI) field 35BS ISO/IEC93
13、14-8:1998 BSI 05-1999 iii Page 7.3.6 Information (INFO) field 35 7.3.7 Frame Check Sequence (FCS) 36 7.3.8 Ending Delimiter (ED) 37 7.3.9 Frame Status (FS) 37 7.4 Timers 38 7.4.1 Token-Holding Timer (THT) 38 7.4.2 Valid-Transmission Timer (TVX) 38 7.4.3 Token-Rotation Timer (TRT) 38 7.4.4 Late Count
14、er (Late_ct) 39 7.4.5 Token Counter (Token_ct) 39 7.5 Frame counts 39 7.5.1 Frame_ct 40 7.5.2 Error_ct 40 7.5.3 Lost_ct 40 7.5.4 Copied_ct 40 7.5.5 Transmit_ct 40 7.5.6 Not_Copied_ct 40 8 Operation 40 8.1 Overview 40 8.1.1 Frame transmission 40 8.1.2 Token transmission 41 8.1.3 Frame stripping 41 8.
15、1.4 Ring scheduling 41 8.1.5 Ring monitoring 43 8.2 Structure 44 8.3 Receiver 46 8.3.1 Token and frame validity criteria 46 8.3.2 State R0: LISTEN 47 8.3.3 State R1: AWAIT_SD (Await Starting Delimiter) 47 8.3.4 State R2: RC_FR_CTRL (Receive Frame Control Field) 48 8.3.5 State R3: RC_FR_BODY (Receive
16、 Frame Body) 48 8.3.6 State R4: RC_FR_STATUS (Receive Frame Status) 50 8.3.7 State R5: CHECK_TK (Check Token) 52 8.4 Transmitter 52 8.4.1 State T0: TX_IDLE (Transmitter Idle) 52 8.4.2 State T1: REPEAT (Repeat) 54 8.4.3 State T2: TX_DATA (Transmit data) 56 8.4.4 State T3: ISSUE_TK (Issue Token) 57 8.
17、4.5 State T4: CLAIM_TK (Claim Token) 58 8.4.6 State T5: TX_BEACON (Transmit Beacon) 59 Annex A (informative) Addressing 68 A.1 General structure 68 A.2 Administration of addresses 68 A.2.1 Locally administered addresses 68 A.2.2 Universally administered addresses 68 A.3 Transmission order 69 A.3.1 R
18、epresentation of addresses 69BS ISO/IEC9314-8:1998 iv BSI 05-1999 Page A.4 Group addresses 70 A.4.1 Broadcast address 70 A.4.2 Assignment of group addresses for use in standards 71 A.4.3 Group addresses assigned for use in FDDI 71 A.5 Source routing addressing 71 A.6 References 71 Annex B (informati
19、ve) Frame Check Sequence 71 B.1 Description 71 B.2 Generation of the FCS 72 B.3 Checking the FCS 72 B.4 Implementation 73 B.5 Related standards 74 Annex C (informative) Bridging 74 C.1 Bridge architectures 74 C.2 Destination Address recognition 75 C.3 Indicator setting 75 C.4 Stripping 75 Annex D (i
20、nformative) Elements of timer calculation 76 Annex E (informative) Bibliography Inside back cover Figure 1 FDDI structure 2 Figure 2 Token ring logical configuration example 11 Figure 3 MAC Receiver state diagram 60 Figure 4 MAC Transmitter state diagram 65 Figure B.1 FCS implementation example 73 T
21、able 1 Interpretation of FC field 48BS ISO/IEC9314-8:1998 BSI 05-1999 v 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
22、participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, govern
23、mental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bod
24、ies for voting. Publication as an International Standard requires approval by at least 75% of the national bodies casting a vote. International Standard ISO/IEC9314-8 was prepared by Joint Technical Committee ISO/IEC JTC 1 Information technology, Subcommittee SC 25, Interconnection of information te
25、chnology equipment. ISO/IEC 9314 consists of the following parts, under the general title Information technology Fibre Distributed Data Interface (FDDI): Part 1: Token Ring Physical Layer Protocol (PHY) (1989); Part 2: Token Ring Media Access Control (MAC) (1989); Part 3: Physical Layer Medium Depen
26、dent (PMD) (1990); Part 4: Single Mode Fibre Physical Layer Medium Dependent (SMF-PMD) 1) ; Part 5: Hybrid Ring Control (HRC) (1995); Part 6: Station Management (SMT); Part 7: Physical Layer Protocol (PHY-2); Part 8: Media Access Control-2 (MAC-2); Part 9: Low-Cost Fibre Physical Medium Dependent (L
27、CF-PMD) (under consideration); Part 10: Token Ring Twisted Pair Physical layer Medium Dependent (TP-PMD) (under consideration); Part 13: Conformance Test Protocol Implementation Conformance Statement Proforma (CT-PICS); Part 20: Physical Medium Dependent Conformance Testing (PMD-ATS) (under consider
28、ation); Part 21: Physical Layer Protocol Conformance Testing (PHY-ATS) (underconsideration); Part 25: Abstract test suite for FDDI Station Management Conformance Testing (SMT-ATS); Part 26: Media Access Control Conformance Testing (MAC-ATS) (under consideration). 1) To be publishedvi blankBS ISO/IEC
29、 9314-8:1998 BSI 05-1999 1 Introduction The Fibre Distributed Data Interface (FDDI), ISO/IEC9314, is intended for use in a high-performance general purpose multi-node network and is designed for efficient operation with a peak data rate of100Mbit/s. It uses a Token Ring architecture with optical fib
30、re as the transmission medium. FDDI provides for hundreds of nodes operating over an extent of tens of kilometres. The Media Access Control (MAC) specifies the lower sublayer of the Data Link Layer for the FDDI. As such, it presents the specifications and services provided for conforming FDDI attach
31、ment devices. MAC specifies the access to the medium, including addressing, data checking, and data framing. MAC also specifies the receiver and transmitter state machines. When the set of basic FDDI standards, ISO/IEC9314, is completed it will include the following standards: a) A Physical Layer Pr
32、otocol (PHY), which specifies the upper sublayer of the Physical Layer of ISO/IEC9314. b) A Physical Layer Media Dependent (PMD), which specifies the lower sublayer of the Physical Layer of ISO/IEC9314. c) A Station Management (SMT), which specifies the local portion of the system management applica
33、tion process of ISO/IEC9314. A number of extensions to ISO/IEC9314 are completed or in process. One extension, ISO/IEC9314-5, for Hybrid Ring Control (HRC), commonly known as FDDI-II, extends the capability of FDDI to handle isochronous data streams at a multiplicity of data rates. Another extension
34、, ISO/IEC9314-4, provides for a single-mode optical fibre version of PMD (SMF-PMD) and will permit optical links of up to 60 km. Other work, addressing alternate PMDs, is aimed at providing low-cost attachments for use in concentrator-to-workstation environments. This work includes a Low-Cost Fibre
35、PMD (LCF-PMD) and a (copper) Twisted Pair PMD (TP-PMD). This part of ISO/IEC9314 for MAC-2 is an enhancement to the original FDDI standard on MAC (ISO9314-2). It is referred to as MAC-2 when it is necessary to distinguish it from the original MAC. Changes include those identified in footnotes to ISO
36、9314-2 as areas that the standards committee intended to change as well as changes that were required for extensions to FDDI, such as FDDI-II and MAC level bridging. MAC-2 also includes editorial corrections and clarifications. 1 Scope This part of ISO/IEC9314 specifies the Media Access Control (MAC
37、), the middle sublayer of the Data Link Layer (DLL), for Fibre Distributed Data Interface (FDDI). FDDI (ISO/IEC9314) provides a high-bandwidth (100 Mbit/s), general-purpose interconnection among information processing systems, subsystems and peripheral equipment, using fibre optics or other transmis
38、sion media. FDDI can be configured to support a sustained data transfer rate of atleast80Mbit/s (10 Mbyte/s). FDDI provides connectivity for many nodes distributed over distances of many kilometres in extent. Certain default parameter values for FDDI (e.g. timer settings) are calculated on the basis
39、 of up to 1 000 transmission links or up to 200 km total fibre path length (typically corresponding to 500 nodes and 100 km of dual fibre cable, respectively); however, the FDDI protocols can support much larger networks by increasing these parameter values. As shown in Figure 1, ISO/IEC9314 consist
40、s of a) A Physical Layer (PL), which is divided into two sublayers: 1) A Physical Medium Dependent (PMD), which provides the digital baseband point-to-point communication between nodes in the FDDI network. The PMD provides all services necessary to transport a suitably coded digital bit stream from
41、node to node. The PMD defines and characterizes the fibre-optic drivers and receivers, medium-dependent code requirements, cables, connectors, power budgets, optical bypass provisions, and physical-hardware-related characteristics. It specifies the point of interconnectability for conforming FDDI at
42、tachments. The initial PMD standard, ISO/IEC9314-3, defines attachment to multi-mode fibre. Additional PMD sublayer standards are being developed for attachment to single-mode fibre and SONET.BS ISO/IEC9314-8:1998 2 BSI 05-1999 2) A Physical Layer Protocol (PHY), which provides connection between th
43、e PMD and the Data Link Layer. PHY establishes clock synchronization with the upstream code-bit data stream and decodes this incoming code-bit stream into an equivalent symbol stream for use by the higher layers. PHY provides encoding and decoding between data and control indicator symbols and code
44、bits, medium conditioning and initializing, the synchronization of incoming and outgoing code-bit clocks, and the delineation of octet boundaries as required for the transmission of information to or from higher layers. Information to be transmitted on the medium is encoded by the PHY using a group
45、transmission code. b) A Data Link Layer (DLL), which is divided into two or more sublayers: 1) An optional Hybrid Ring Control (HRC), which provides multiplexing of packet and circuit switched data on the shared FDDI medium. HRC comprises two internal components, a Hybrid Multiplexer (H-MUX) and an
46、isochronous MAC (I-MAC). H-MUX maintains a synchronous 1254s cycle structure and multiplexes the packet and circuit switched data streams, and I-MAC provides access to circuit switched channels. Figure 1 FDDI structureBS ISO/IEC 9314-8:1998 BSI 05-1999 3 2) A Media Access Control (MAC), which provid
47、es fair and deterministic access to the medium, address recognition, and generation and verification of frame check sequences. Its primary function is the delivery of packet data, including frame generation, repetition, and removal. The definition of MAC is contained in this part of ISO/IEC9314. 3)
48、An optional Logical Link Control (LLC), which provides a common protocol for any required packet data adaptation services between MAC and the Network Layer. LLC is not specified by FDDI. 4) An optional Circuit Switching Multiplexer (CS-MUX), which provides a common protocol for any required circuit
49、data adaptation services between I-MAC and the Network Layer. CS-MUX is not specified by FDDI. c) A Station Management (SMT), which provides the control necessary at the node level to manage the processes under way in the various FDDI layers such that a node may work cooperatively on a ring. SMT provides services such as control of configuration management, fault isolation and recovery, and scheduling policies. The MAC definition contained herein is designed to be as independent as possible from both the physical medi
