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iSCSI: The Universal Storage Connection

Book Description

iSCSI: The Universal Storage Connection is an informative overview and in-depth guide to the emerging iSCSI standard, the technology that enables data storage, access, and management over networks, intranets, and the Internet. The iSCSI protocol reduces the total cost of ownership of shared storage solutions and enables an organization to tie together disparate systems and data, including both server class systems and laptop and desktop systems. Numerous leading technology companies, including IBM®, Cisco Systems®, and Intel®, are currently supporting iSCSI initiatives.

Written for network and data storage professionals, this comprehensive book introduces iSCSI and explores its growing role within the data storage industry. It describes each element of the technology in detail—from session establishment through error handling—and examines the relationship between iSCSI and the SCSI protocol from which it evolved.

Specific topics discussed include:

  • iSCSI's use in small office, midrange, and high-end settings

  • TCP/IP fundamentals, and how they apply to iSCSI

  • The importance of data integrity

  • New hardware that addresses bandwidth and latency issues

  • iSCSI naming conventions

  • The establishment of a communication path between the host system and storage controller

  • Commands and data sequencing

  • Control of the flow of commands

  • Task management

  • Error handling

  • Companion technologies, including discovery and security processes

  • Backup and disaster preparation

  • iSCSI performance issues

  • In addition, the book includes an explanation of the technologies that hardware vendors are implementing to permit direct memory placement of iSCSI messages without additional main processor involvement.

    A helpful icon appears throughout the book, mapping out appropriate reading tracks based on your technical level.

    Comprehensive, clearly written, and organized for easy access, this iSCSI handbook serves as both an excellent starting point for those involved in data storage solutions and a guide to understanding the technically detailed Internet Engineering Task Force (IETF) iSCSI Standards document.

    Table of Contents

    1. Credits and Disclaimer
    2. Preface
    3. Chapter 1 The Background of SCSI
      1. SCSI Bus Interconnect
      2. Fibre Channel Interconnect
      3. iSCSI Interconnect
      4. File Servers and NAS
      5. Chapter Summary
    4. Chapter 2 The Value and Position of iSCSI
      1. To the Reader
      2. The Home Office
        1. The Home Office and Serial ATA Drives
      3. The Small Office
      4. The Midrange
      5. The High End
        1. The Campus
        2. The Satellite
        3. The At-Distance Site
        4. The Central Site
      6. FC and iSCSI
      7. Chapter Summary
    5. Chapter 3 The History of iSCSI
      1. To the Reader
      2. SCSI over TCP/IP
        1. Measurements
      3. Cisco and IBM's Joint Effort
      4. iSCSI and IETF
      5. The End of the Story
      6. Chapter Summary
    6. Chapter 4 An Overview of iSCSI
      1. To the Reader
      2. TCP/IP
        1. TCP/IP Summary
      3. iSCSI-Related Protocol Layers
        1. Protocol Summary
      4. Sessions
        1. Session Summary
      5. Protocol Data Unit (PDU) Structure
        1. PDU Structure Summary
      6. iSCSI and TOE Integration on a Chip or HBA
        1. TOE Integration Summary
      7. Checksums and CRC (Digests)
        1. Checksum and CRC Digest Summary
      8. Naming and Addressing
        1. Details of Naming and Addressing
        2. Naming and Addressing Summary
      9. Chapter Summary
    7. Chapter 5 Session Establishment
      1. To the Reader
      2. Introduction to the Login Process
      3. Login and Session Establishment
      4. Login PDUs
        1. The Login Request PDU
        2. The Login Response PDU
      5. iSCSI Sessions
        1. Authentication Routines
      6. Login Keywords
        1. Keywords and the Login Process
      7. Discovery Session
      8. Chapter Summary
    8. Chapter 6 Text Commands and Keyword Processing
      1. To the Reader
      2. Text Requests and Responses
        1. PDU Fields
      3. Text Keywords and Responses
        1. Rules for Key=Value Pairs
        2. Rules for Keyword Value Negotiation
        3. Rules for Negotiation Flow
        4. Rules for Negotiation Failure
      4. Chapter Summary
    9. Chapter 7 Session Management
      1. To the Reader
      2. Initiator Session ID
      3. Connection Establishment
      4. Data Travel Direction
      5. Sequencing
      6. Resending Data or Status
        1. Recap
      7. Chapter Summary
    10. Chapter 8 Command and Data Ordering and Flow
      1. To the Reader
      2. Command Ordering
      3. Command Windowing
      4. Initiator Task Tag
        1. Design Example: Direct Host Memory Placement
      5. Data Ordering
      6. Target Transfer Tag
      7. Data Placement (A Form of RDMA)
      8. Chapter Summary
    11. Chapter 9 Structure of iSCSI and Relationship to SCSI
      1. To the Reader
      2. iSCSI Structure and SCSI Relationship
      3. SCSI Nexus
      4. Chapter Summary
    12. Chapter 10 Task Management
      1. To the Reader
      2. Tagged and Untagged Texts
      3. Chapter Summary
    13. Chapter 11 Error Handling
      1. To the Reader
      2. Error Recovery Levels
      3. Error Recovery Level 0
      4. Error Recovery Level 1
        1. Header Digest Recovery at the Initiator Side
        2. Header Digest Recovery at the Target Side
        3. Data Digest Recovery
      5. Error Recovery Level 2
      6. Chapter Summary
    14. Chapter 12 Companion Processes
      1. To the Reader
      2. Boot Process
      3. Discovery Process
        1. Discovery Using Administrative Specifications
        2. Discovery Using SendTargets
        3. Discovery Using the Service Location Protocol
        4. Discovery Using iSNS
      4. Security Process
      5. To the Reader
        1. IPsec Features
        2. Access Control Lists
      6. MIB and SNMP
      7. Chapter Summary
    15. Chapter 13 Synchronization and Steering
      1. To the Reader
      2. Main Memory Replacement
        1. Errors and Congestion
        2. Missing TCP Segments and Marking
      3. Fixed-Interval Markers
        1. FIM Pointers
        2. Marker Implementation
        3. FIM Synchronization Scheme
      4. TCP Upper-Level-Protocol Framing (TUF)
      5. The TUF Scheme
        1. The TUF Header
        2. Advantages and Disadvantages
      6. TUF/FIM
      7. Chapter Summary
    16. Chapter 14 iSCSI Summary and Conclusions
      1. To the Reader
      2. Summary
        1. iSCSI Development History
      3. Conclusions
        1. iSCSI Network Management
        2. Ease of Administration
        3. Backup and Disaster Preparation
        4. Performance
      4. The Future
      5. Summary of Conclusions
    17. Appendix A iSCSI Function PDUs
      1. Serial Number Arithmetic
      2. Asynchronous Message PDU
      3. Login Request PDU
        1. ISID, TSIH, and CID Values
      4. Login Response PDU
      5. Logout Request PDU
        1. Notes on the Logout Request PDU
        2. Implicit Termination of Tasks
      6. Logout Response PDU
      7. NOP-In PDU
      8. NOP-Out PDU
      9. Ready to Transfer (R2T) PDU
        1. Notes on the R2T PDU
      10. Reject PDU
        1. Notes on the Reject PDU
      11. SCSI (Command) Request PDU
      12. SCSI (Command) Response PDU
      13. SCSI Data-In PDU
      14. SCSI Data-Out PDU
      15. SNACK Request PDU
        1. Resegmentation
        2. Notes on the SNACK Request PDU
      16. Task Management Function Request PDU
        1. Notes on the Task Management Function Request PDU
      17. Task Management Function Response PDU
        1. Notes on the Task Management Function Response PDU
      18. Text Request PDU
      19. Text Response PDU
    18. Appendix B Keys and Values
      1. AuthMethod
      2. AuthMethod Keys
      3. DataDigest
      4. DataPDUInOrder
      5. DataSequenceInOrder
      6. DefaultTime2Retain
      7. DefaultTime2Wait
      8. ErrorRecoveryLevel
      9. FirstBurstLength
      10. HeaderDigest
      11. IFMarker
      12. IFMarkInt
      13. ImmediateData
      14. InitialR2T
      15. InitiatorAlias
      16. InitiatorName
      17. MaxBurstLength
      18. MaxConnections
      19. MaxOutstandingR2T
      20. MaxRecvDataSegmentLength
      21. OFMarker
      22. OFMarkInt
      23. SendTargets
      24. SessionType
      25. TargetAddress
      26. TargetAlias
      27. TargetName
      28. TargetPortalGroupTag
      29. X-<VendorSpecificKey>
      30. X#<IANA-registered-string>
    19. Appendix C SCSI Architecture Model
      1. SCSI–iSCSI Mappings
      2. Consequences of the Model
        1. I-T Nexus State
        2. SCSI Mode Pages
    20. Appendix D Numbers, Characters, and Bit Encodings
      1. Text Format
    21. Appendix E Definitions
    22. Appendix F Acronyms
    23. Appendix G References and Web Pointers
      1. Basic References for iSCSI
      2. References for SCSI-Related Items
      3. References for iSCSI Security and IPsec/IKE
      4. References That Indirectly Affect iSCSI
    24. Index