Last updated: 15 Jan 2002Developed by GUSTECH1 Fibre Channel with SCSI A few notes about ‘Fibre Channel’ Some “FINE” Print: DISCLAIMER: This information

Last updated: 15 Jan 2002

Developed by GUSTECH 1

Fibre Channelwith SCSI

A few notes about ‘Fibre Channel’Some “FINE” Print: DISCLAIMER:

This information is intended ONLY as an overview and introduction to Fibre Channel with SCSI and is NOT a specification of any kind, nor is it a substitution for official course material prepared by Solution Technology.

GUSTECH, Solution Technology Inc., and the instructor make no warranty and assume no liability arising from the application or use of any information described herein, and assume no responsibility for errors appearing in this

document or for any claims that the concepts or details discussed or disclosed in these materials are proprietary to any person or company. Students are strongly urged to clear any designs proposed for products with their patent and

copyright council. Note: company, brand, product, trade, and other names used in this document are trademarks of their respective holders.



Fibre Channel with SCSI

Brief Synopsis Fibre Channel Topologies and

General Characteristics Fibre Channel Architectural

Overview (classes & layers) Fibre Channel “Payloads” SCSI “over” Fibre Channel



Topologies & Characteristics

Point-to-Point:

N-Port

Tx Rx

N-Port

TxRx

ex.: Host-to-Host, orHost-to-single Disk or

Disk Array.

Bandwidth = 100%Full Duplex

Fabric (switch)General View:

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

RxF

-Por

t

Rx

Tx

F-P

ort

Rx

Tx

F-P

ort

Rx

Tx

Fabric Communications Models can be arranged as one-to-one, one-to-many, and one-to-all.





Fabric (switch), Dedicated Connection Mode:

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort

Rx

Tx

F-P

ort

Rx

Tx

F-P

ort

Rx

TxF_BSY

F_BSY

Pair of Point-to-Point connections, deterministic and in-order delivery due to dedicated links; shown with full-resource reservation (non-virtual circuit). Connections made

before communications start, and need to be dismantled when finished.

ex.: Class 1 Service, likea computer I/O Channel




Packets of information (Frames) are routed based on the destination address in the frame header. No paths or resources are reserved. Successive frames may be routed over different paths and may be received out of order. Non-deterministic.

Bandwidth: as available

Fabric (switch), Connectionless Mode:

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

Frame

Frame

FrameFrame

Frame

Frame

FrameFrame

FrameFrame

Frame

Frame

Frame

Frame

Frame

Frame

Frame

Note: Mixed Mode Fabric is a switch that can simultaneously handle Connection and Connectionless Modes.

ex.: Class 2 & 3 Service, likeresource multiplexing and

Internet non-acknowledgement




Bandwidth = Fixed% as needed

Fabric (switch), Virtual Circuit (fractional bandwidth) Mode:

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort

Rx

Tx

F-P

ort

Rx

Tx

F-P

ort

Rx

Tx

Point-to-Point connections, deterministic and in-order delivery due to dedicated links; shown with dedicated, partial-resource reservations, or virtual circuits. Connections

made before communications start, and need to be dismantled when finished.

These circuits are managed by the Quality of Service Facilitator

10%

15%25%

25%25%

25%

60%40%

ex.: Class 4 Service, likeData acquisition & video




NL-Port:

NL-Port

Tx Rx

ex.: Arrays ofI/O devices on

a Controller


Arbitrated Loop:Private loop shown:

Up to 126 nodes. Only two communicating (virtual point-to-point) at a time. Others “repeat”.

Repeater

NL

-Por

t

Tx

Rx

NL

-Por

t

Rx

Tx

NL

-Por

t

Rx

Tx

NL

-Por

t

Rx

Tx

NL

-Por

tTx

Rx

NL

-Por

t

Tx

Rx

Not shown:By-Pass Circuitry

HUBs are often usedto develop loops andto enable by-pass and

reconfigurationcapabilities.

The Loop Port State Machine performs

initialization, arbitration, opening

and closing loops, and includes the repeater




Arbitrated Loop: Public loop shown:

Up to 127 nodes. Only two communicating (virtual point-to-point) at a time. Others “repeat”. Fabric node enables connection of loop to the “outside world”

NL

-Por

t

Tx

Rx

NL

-Por

t

Rx

Tx

NL

-Por

t

Rx

Tx

NL

-Por

t

Tx

Rx

NL

-Por

t

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

N-P

ort

Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

F-P

ort Tx

Rx

F-P

ort

Rx

Tx

F-P

ort

Rx

Tx

FL

-Por

t

Rx

Tx

LOOP FABRIC

NOTE: Only one FL-port per Arbitrated Loop



Architectural OverviewLayers and Classes

Physical Layer: Copper, Single Mode Fiber, Multimode Fiber133 Mb/s, 256 Mb/s, 531 Mb/s, 1.06 Gb/s, 2.12 Gb/s, 4.25 Gb/s

FC Layer: OSI Layer:

FC-0 1

Encode/Decode Layer: “Link” transmission protocol,(8B/10B) Serializing, (10B/8B) Deserializing, and Error Detection

FC-1 2

Framing Protocol Layer: “Transport” signaling including:Flow control, frame structure, and byte sequences

FC-2 4

Common Services: “Session” Management Services,Name Server, Alias Server, and Key Server

FC-3 5

Application: “Channels”: SCSI, SBCCS, HIPPI, IPI;“Networks”: IP, 802.2; “Multimedia”: Audio, Video

FC-4 7

The five layers of Fibre Channel



Architectural OverviewLayers and Classes

6

Fractional Bandwidth Connection: Same as Class 1 except latency and partialbandwidth usage are managed by a Quality of Service Facilitator (FFFFF9); “Virtual Circuit”

4

3

2

Acknowledged Connection: Established Connection; 100% Bandwidth;In-Order Delivery; Frame Receipt Acknowledged; End-to-End & Link-Level Flow Control

1

The five classes of service of Fibre Channel

Acknowledged Connectionless: NO Established Connection; Bandwidth,Latency, and In-Order Delivery are NOT guaranteed; Frame Receipt is

Acknowledged; does use End-to-End & Link-Level Flow Control

Unacknowledged Connectionless: NO Established Connection, NO Bandwidthor In-Order Delivery guarantees, NO Frame Receipt Acknowledgement, NO End-to-End

Flow Control; Does use Link-Level Flow Control; often called “Ship & Pray”

Unidirectional Connection: Same as Class1modified for reliable one-to-many multicast and pre-emption; uses a Multicast Server (FFFFF5)



Fibre Channel “Payloads”a SCSI kind of view

An exchange is composed of one or more non-

concurrent sequencesfor a single operation.

Each transfer is accomplished with a separate sequence or

Information Unit.Each sequence consists of

one or more frames, which are the smallest indivisible packet of data that is sent

over the link.

EXCHANGE

FRAMELike a SCSI Read CDB,

Data, and Status

FRAME FRAME FRAME FRAME

FRAME

First Sequence: CDB Frame

Second Sequence: Data IN Frames

End of Second Sequence: “Status” FrameUnique “Exchange” ID

is identical to a Queue Tag

EXCHANGE

FRAME Like a SCSI Test Unit Ready CDB, and Status

FRAME

First Sequence: CDB Frame

Last Sequence: “Status” Frame

Unique “Exchange” IDis identical to a Queue Tag

INITIATOR TARGET



Fibre Channel “Payloads”details on FRAMES

F

I

L

L

W

O

R

D

Start

of

Frame

1 word

Frame Header

6 words

Optional Headers

0-64 bytes

Payload

Information Units

Fill

0-3

bytes

CRC

1 word

End

of

Frame

1 word

F

I

L

L

W

O

R

D

DATA FIELD (0-2112 Bytes)

F R A M E

R_CTL Destination Address (D_ID) (Target)

CS_CTL Source Address (S_ID) (Initiator)

TYPE Frame Control (F_CTL)

SEQ_ID DF_CTL SEQ_CNT

OX_ID (Q_tag#) RX_ID

Parameter Field (PARAM)

Routing Control Flags, Info types

Class-specific control information

Protocol (FC-4) Type in this frameSCSI-FCP = 8

Sequence # this frame belongs to

Originator’s Exchange ID #

Multi-purpose parameter field, like:Relative Offset or Task Retry Identifier

Destination N_port Identifier

Source N_port Identifier

Frame Control field

Sequential count of frames

Responder’s Exchange ID #,for an exchange established byan Originator and identified byan OX_ID



SCSI over Fibre ChannelDetails on PAYLOADS: SCSI Information Units

F

I

L

L

W

O

R

D

Start

of

Frame

1 word

Frame Header

6 words

Optional Headers

0-64 bytes

Payload

Information Units

Fill

0-3

bytes

CRC

1 word

End

of

Frame

1 word

F

I

L

L

W

O

R

D

DATA FIELD (0-2112 Bytes)

F R A M E

FC Name:Cate-gory SCSI Function

# of WordsFunction

# of WordsData

NOTES:

FCP_CMND 6Command (&

embedded messages)8 0

Messages in Task Codes & Flags

FCP_XFR_

RDY5 (no direct equivalent) 3 0

“Transfer Ready” is optional for reads

FCP_DATA 1 Data (in and out) 0 Up to 528 optional

FCP_RESP 7 Status (& sense data) 8 VariableSense data length

per Word 4

FCP_CONF 3 (no direct equivalent) No payload 0 Confirm Status



SCSI over Fibre ChannelDetails on FCP_CMND PAYLOAD, Information Category = 6

FC Label WORD BYTE0 Byte1 Byte2 Byte3

FCP_LUN0 First Level LUN Addressing (Byte 1) Second Level LUN Addressing

1 Third Level LUN Addressing Fourth Level LUN Addressing

FCP_CNTL 2 CMD Ref. Num Task Codes Task Mgmt Flags Exec Mgmt Codes

FCP_CDB

3 1st byte of CDB 2nd byte of CDB 3rd byte of CDB 4th byte of CDB

4 5th byte of CDB 6th byte of CDB 7th byte of CDB 8th byte of CDB



Add_CDB 7+? Additional CDB Bytes for “variable” (Group 3) CDB’s

FCP_DL Size of data buffer allocated by Initiator

BITS:2 1 00 0 00 0 10 1 01 0 01 0 1others

Simple QHead of QOrdered QACA QUntaggedreserved

Read Data = Bit 1Write Data = Bit 0Additional CDB Length = Bits 7..2

Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0

Terminate TaskClear ACATarget ResetReset LUNreservedClear Task SetAbort Task Setreserved

Command Reference Number = Initiator assigned

“order” numbers enabling “Precise

Order of Delivery” capabilities: “1,+1 -> 255 ->, no 0”

Now obsolete



SCSI over Fibre ChannelDetails on FCP_XFER_RDY PAYLOAD, Information Category = 5

FC Label WORD BYTE 0 Byte 1 Byte 2 Byte 3

DATA_RO 0 Relative Offset for following data sequence

BURST_LEN 1 Burst Length = Number of bytes in following data sequence

reserved 2 reserved

Optional for Read Commands

Not to exceed “Maximum Burst Size” as set by Initiator using MODE PAGE management on

Disconnect-Reconnect Mode Page



SCSI over Fibre ChannelDetails on FCP_DATA PAYLOAD, Information Category = 1

WORD BYTE 0 Byte 1 Byte 2 Byte 3

0 Data

…

n Data

Three different types of SCSI data:

Command Parameter (select)

Command Response (sense)

Read/write “information”



SCSI over Fibre ChannelDetails on FCP_RESP PAYLOAD, Information Category = 7

FC Label WORD BYTE 0 Byte 1 Byte 2 Byte 3

reserved 0 reserved

reserved 1 reserved

FCP_STATUS 2 reserved reserved Validity Flags SCSI Status Byte

FCP_RESID 3 Number of residual data bytes not transferred in the FCP_DATA

FCP_SNS_LEN 4 Sense Data Length

FCP_RSP_LEN 5 Response Information length: 8 bytes per FCP2

FCP_RSP_INFO6 reserved reserved reserved RSP_CODE

7 reserved reserved reserved reserved

FCP_SNS_INFO8

Sense Information: variable length per word 4: FCP_SNS_LENn

Bit Function:

0 RSP_LEN_VALID

1 SNS_LEN_VALID

2 RESID_OVER

Bit Function:

3 RESID_UNDER

4 CONF_REQ

7-5 reserved

Response to Command’s Task Management Flags:00 = no failure or function complete01 = Data length different than Burst_Len02 = FCP_CMND Fields invalid03 = DATA RO mismatch with XFER_RDY

04 = function not supported05 = function failed06-FF reserved




NOT PRESENTED:

Tons of details

About 4 days, 7 hours, and 30

minutes of rest of the data

The importance of the rest of the

information




Recommended Study:Courses from Solution

Technology:

Fibre Channel Concepts and

Solutions Comprehensive Introduction to

Fibre Channel Hands-ON Fibre Channel

Documents

Last updated: 15 Jan 2002Developed by GUSTECH1 Fibre Channel with SCSI A few notes about ‘Fibre Channel’ Some “FINE” Print: DISCLAIMER: This information