VeEX MTX150 Series, Руководство пользователя

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215 © VeEX Inc. All Rights Reserved. Fiber Channel
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When supported by FC_Ports, the Priority field shall be used to resolve resource contention or
to determine the order to deliver frames. The definition and use of the Priority field is class
dependent.
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S_ID Address Identifier:
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The S_ID is a three-byte field (Word 1, Bits 23-0) that contains the address identifier of the
source Nx_Port.
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Type (Data Structure Type):
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The data structure type (TYPE) is a one-byte field (Word 2, Bits 31-24) that identifies the pro-
tocol of the frame content for Data frames.
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Frame Control (F_CTL):
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The Frame Control (F_CTL) field (Word 2, Bits 23-0) is a three-byte field that contains control
information relating to the frame content such as exchange, retransmission, or sequence con-
trol. It is also used to identify the function of the
CS_CTL/P field.
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Sequence Identifier (SEQ_ID):
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The SEQ_ID is a one-byte field (Word 3, Bits 31-24) assigned by the Sequence Initiator that is
unique for a specific D_ID and S_ID pair while the Sequence is open.
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Both the Sequence Initiator and the Sequence Recipient track the status of frames within the
Sequence using fields within the Sequence_Qualifier.
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Data Field Control (DF_CTL):
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Data Field Control (DF_CTL) is a one-byte field (Word 3, Bits 23-16) that specifies the pres-
ence of optional headers at the beginning of the Data_Field for Device_Data or Video_Data
frames.
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DF_CTL bits are not meaningful on Link_Control or Basic Link Service frames.