ISO/IEC 14165-151:2017 情報技術—ファイバーチャネル—パート151：ファイバーチャネルBaseT（FC-BaseT） | ページ 6

3.1 用語と定義

このドキュメントでは、次の用語と定義が適用されます。

ISO および IEC は、次のアドレスで標準化に使用する用語データベースを維持しています。

3.4.1 予想: この規格が想定する設計モデルにおけるハードウェアまたはソフトウェアの動作を記述するために使用されるキーワード。他のハードウェアおよびソフトウェア設計モデルも実装できます。

3.4.2 無視: 未使用のビット、バイト、ワード、フィールド、またはコード値を記述するために使用されるキーワード。無視されたビット、バイト、ワード、フィールド、またはコード値の内容または値は、受信デバイスによって検査されず、送信デバイスによって任意の値に設定される場合があります。

3.4.3 無効: 不正またはサポートされていないビット、バイト、ワード、フィールド、またはコード値を記述するために使用されるキーワード。無効なビット、バイト、ワード、フィールド、またはコード値を受信すると、エラーとして報告されます。

3.4.4 必須: この規格で定義されているように実装する必要がある項目を示すキーワード。

3.4.5 may: 選択の柔軟性を示すキーワードで、暗黙の好みはありません (「may or may not」と同等)

3.4.6 may not: 選択の柔軟性を示すキーワードであり、暗黙の好みはありません (「may or may not」と同等)

3.4.7 obsolete: 項目が以前のファイバー チャネル標準で定義されていたが、この標準から削除されたことを示すキーワード。

3.4.8 オプション: この規格で実装する必要のない機能を説明するキーワード。ただし、この標準で定義されているオプション機能が実装されている場合は、この標準で定義されているとおりに実装する必要があります。

3.4.9 予約済み: 将来の標準化のために取っておかれるビット、バイト、ワード、フィールド、およびコード値を参照するキーワード。予約済みのビット、バイト、ワード、またはフィールドは、ゼロに設定するか、この標準の将来の拡張に従って設定する必要があります。受信者は、予約済みのビット、バイト、ワード、またはフィールドのゼロ値をチェックする必要はありません。

3.4.10 制限付き: 他のファイバー チャネル標準で使用するために確保されているビット、バイト、ワード、およびフィールドを指すキーワード。制限されたビット、バイト、ワード、またはフィールドは、この規格で定義された要件のために、予約済みのビット、バイト、ワード、またはフィールドとして扱われるものとします。

3.4.11し なければならない: 必須要件を示すキーワード。設計者は、この標準に準拠する他の製品との相互運用性を確保するために、そのような必須要件をすべて実装する必要があります。

3.4.12 should: 選択の柔軟性を示すキーワード。 「強くお勧めします」に相当します。

3.4.13 x または xx: ビットまたはフィールドの値は関係ありません。

3 Terms, definitions, abbreviations, symbols, and conventions

3.2 Editorial conventions

In this standard, a number of conditions, mechanisms, sequences, parameters, events, states, or similar terms are printed with the first letter of each word in uppercase and the rest lowercase (e.g., Exchange, Class). Any lowercase uses of these words have the normal technical English meanings.

Lists sequenced by letters (e.g., a-red, b-blue, c-green) show no ordering relationship between the listed items. Numbered lists (e.g., 1-red, 2-blue, 3-green) show an ordering relationship between the listed items.

The ISO convention of numbering is used (i.e., the thousands and higher multiples are separated by a space and a comma is used as the decimal point.) A comparison of the American and ISO conventions are shown in table 1.

In case of any conflict between figure, table, and text, the text, then tables, and finally figures take precedence.

In all of the figures, tables, and text of this document, the most significant bit of a binary quantity is shown on the left side.

When the value of a bit or field is not relevant, x or xx appears in place of a specific value.

Unless stated otherwise, numbers that are not immediately followed by lower-case b or h are decimal values, numbers immediately followed by lower-case b (xxb) are binary values, and numbers or upper case letters immediately followed by lower-case h (xxh) are hexadecimal values.

A numeric range is indicated by listing the two extremes separated by “..” (e.g., “1 .. 6” indicates the range from 1 to 6, including 1 and 6).

3.3 Abbreviations, acronyms, and symbols

Abbreviations, acronyms, and symbols applicable to this standard are listed. Definitions of several of these items are included in 3.1.

3.4 Keywords

3.5 State Diagram notation

3.5.1 State Diagram conventions

The operation of a protocol may be described by subdividing the protocol into a number of interrelated functions.The operation of the functions may be described by state diagrams. Each diagram represents the domain of a function and consists of a group of connected, mutually exclusive states. Only one state of a function is active at any given time (see figure 1).

Each state that the function is able to assume is represented by a rectangle. These are divided into two parts by a horizontal line. In the upper part the state is identified by a name in capital letters. The lower part contains the name of any ON signal that is generated by the function. Actions are described by short phrases and enclosed in brackets.

All permissible transitions between the states of a function are represented graphically by arrows between them. A transition that is global in nature (e.g., an exit condition from all states to the IDLE or RESET state) is indicated by an open arrow. Labels on transitions are qualifiers that shall be fulfilled before the transition is taken. The label UCT designates an unconditional transition. Qualifiers described by short phrases are enclosed in parentheses.

State transitions and sending and receiving of messages occur instantaneously. The actions inside a state block execute instantaneously. Actions inside state blocks are atomic (i.e., uninterruptible). When a state is entered and after performing all the actions listed in a state block one time, the state block then continuously evaluates its exit conditions until one is satisfied, at which point control passes through a transition arrow to the next block. While the state awaits fulfillment of one of its exit conditions, the actions inside do not implicitly repeat.

Valid state actions may include .indication and .request messages. No actions are taken outside of any state block.

The following convention is used to describe a term-assignment statement that is associated with a transition:

• a) The character “: ” (colon) is a delimiter used to denote that a term assignment statement follows; and
• b) The character “⇐” (left arrow) denotes assignment of the value following the arrow to the term preceding the arrow.

The state diagrams contain the authoritative statement of the functions they depict. When apparent conflicts between descriptive text and state diagrams arise, the state diagrams are to take precedence. However, such precedence does not override any explicit description in the text that has no parallel in the state diagrams.

The models presented by state diagrams are intended as the primary specifications of the functions to be provided. However, it is important to distinguish between a model and a real implementation. The models are optimized for simplicity and clarity of presentation, while any realistic implementation may place heavier emphasis on efficiency and suitability to a particular implementation technology. It is the functional behavior of any unit that shall match the standard, not its internal structure. The internal details of the model are useful only to the extent that they specify the external behavior clearly and precisely.

3.5.2 State Diagram variables

State variables are of two types, variables with no default value and variables with a default value. Variables with no default value, once set retain their value as long as succeeding blocks contain no references to them. Variables with default value evaluate to the variable default value in each state where the variable value is not explicitly set.

3.5.3 State Diagram timers

All timers operate in the same fashion. A timer is reset and starts counting upon entering a state where"start x_timer" is asserted. Time"x" after the timer has been started,"x_timer_done" is asserted and remains asserted until the timer is reset. At all other times,"x_timer_not_done" is asserted. When explicitly entering a state where"start x_timer" is asserted, the timer is reset and restarted even if the entered state is the same as the exited state. In addition, a timer is reset and stops counting upon entering a state where"stop timer" is asserted.

3.5.4 State transitions

The following terms are valid transition qualifiers:

• a) Boolean expressions;
• b) An event such as the expiration of a timer: timer_done;
• c) An event such as the reception of a message: PMA_UNITDATA.indication;
• d) An unconditional transition: UCT;
• e) A branch taken when other exit conditions are not satisfied: ELSE.

Any open arrow (an arrow with no source block) represents a global transition. Global transitions are evaluated continuously whenever any state is evaluating its exit conditions. When a global transition becomes true, it supersedes all other transitions, including UCT, returning control to the block pointed to by the open arrow.

3.5.5 Operators

The state diagram operators are shown in table 2.

Bibliography