T1: A Survival Guide

T1: A Survival Guide

by Matthew Gast
Released August 2001
Publisher(s): O'Reilly Media, Inc.
ISBN: 9780596001278

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Book description

If you haven't worked with T1 before, you could be in for an unpleasant surprise. If you have, you'll already know that T1, the current network standard for business and professional Internet access, is neither efficient, easy to use, nor particularly well-suited to data transmission. T1: A Survival Guide, a practical, applied reference on T1 data transport, is a life raft for navigating the shoals of a 40-year-old technology originally designed for AT&T's voice network. Throughout T1's long life, network administrators have mainly learned it by apprenticeship, stumbling on troubleshooting tidbits and filing them away until they were needed again. This book brings together in one reference the information you need to set up, test, and troubleshoot T1. T1: A Survival Guide covers the following broad topics:

  • What components are needed to build a T1 line, and how those components interact to transmit data effectively

  • How to use standardized link layer protocols to adapt the T1 physical layer to work with data networks

  • How to troubleshoot problems and work with the telephone company, equipment manufacturers, and Internet service providers

In spite of its limitations, T1 is a proven, reliable technology that currently meets the need for medium-speed, high reliability Internet access by institutions of many sizes, and it's likely to be around for a while. T1: A Survival Guide will take the guesswork out of using T1 as a data transport.

Table of contents

  1. T1: A Survival Guide
    1. Preface
      1. Audience
      2. Overture for Book in Black and White, Opus 3
      3. Assumptions This Book Makes
      4. Conventions Used in This Book
      5. How to Contact Us
      6. Acknowledgments
    2. 1. History of the U.S. Telephone Network
      1. 1876-1950: Analog Beginnings
      2. 1951-1970:The Birth of T-carrier
        1. The Transistor and Computerization
        2. Digitalization
      3. 1970-Present:The Modern Telephone Network
        1. The Problems with T-carrier
        2. The Rise of Data and the Internet
    3. 2. T1 Architectural Overview
      1. Telecommunications Puzzle Pieces
        1. From the Router to the CSU/DSU with V.35
        2. The CSU/DSU: Your Network to the Telco Network
        3. The End Span: From the CSU/DSU to the CO
        4. The End Span and Entry intothe Telecommunications World
    4. 3. Basic Digital Transmission on Telephone Networks
      1. Introduction to DS0
      2. Alternate Mark Inversion
        1. Timing and Synchronization
      3. B8ZS and Clear Channel Capability
    5. 4. Multiplexing and the T-carrier Hierarchy
      1. Building the T-carrier Hierarchywith Multiplexing
        1. Multiplexing to Form the T1
        2. Ones Density and the T1
      2. The Original Superframe
        1. Alarms and the Superframe
      3. The Extended Superframe (ESF)
        1. ESF Signaling
          1. Code words: ESF alarms and instructions
          2. ESF performance reporting
      4. Telephone Signaling on T1 Links
    6. 5. Timing, Clocking,and Synchronization in the T-carrier System
      1. A Timing Taxonomy
      2. T1 Circuit Timing
        1. Receive Clock Inference on the Network Interface
        2. Transmit Clocking at the Network Interface
          1. Master/slave timing (also called network or loop timing)
          2. Internal timing
        3. Clocking at the Data Port
          1. Receive clock timing
          2. Internal data port clocking
          3. External data port clocking
          4. Inverting the internal clock signal
      3. Slips: When Timing Goes Bad
        1. Avoiding Slips
    7. 6. Mysteries of theCSU/DSU
      1. Line Build Out: Moving BetweenTheory and Practice
        1. Long-Haul Build Out
        2. Short-Haul Build Out (Line Equalization)
        3. Configuring LBO Correctly
      2. T1 CSU/DSUs
        1. RAI/Yellow Alarm Signal
        2. Keepalive/AIS
        3. Loopback and Other Test Functions
      3. CSU/DSU Configuration
      4. Summary of Settings
    8. 7. Connecting the Umbilicus: GettingT1 Connectivity
      1. Ordering
      2. T1 Installation and Termination
        1. The Demarc
        2. Circuit Identification Information
      3. Pre-Connection Tasks
      4. Trading Packets
        1. Troubleshooting
      5. Post-Connection
    9. 8. High-Level Data Link Control Protocol (HDLC)
      1. Introduction to HDLC
      2. HDLC Framing
        1. Information Frames (I-Frames)
        2. Supervisory Frames (S-Frames)
        3. Unnumbered Frames (U-Frames)
        4. HDLC Transparency and Bit Stuffing
      3. Cisco HDLC
        1. SLARP
          1. Polling, sequence numbers, and the keepalive
        2. Configuring Cisco HDLC
    10. 9. PPP
      1. Introduction to PPP
      2. PPP Logical Link Statesand State Machines
      3. PPP Encapsulation and Framing
        1. Transparency
      4. Link Control Protocol (LCP)
        1. The LCP State Engine
        2. Relation of Link Managementto the LCP State Engine
          1. Link initialization
          2. Link configuration
          3. Link termination
        3. LCP Frames
          1. Configuration messages (codes 1, 2, 3, and 4)
          2. Termination messages (codes 5 and 6)
          3. Code- and protocol-rejection messages (codes 7 and 8)
          4. Link integrity messages (codes 9, 10, and 11)
          5. Identification message (code 12)
          6. Other messages
        4. LCP Configuration Options
          1. Maximum Receive Unit (code 1)
          2. Quality protocol (code 4)
          3. Magic number (code 5)
          4. Numbered Mode (code 11)
          5. Multilink MRRU, SSN, and ED (codes 17, 18, and 19)
      5. PPP Network Controland the IP Control Protocol
        1. RFC 1172-Style Address Assignment(IP Addresses; IPCP Option 1)
        2. RFC 1332-Style Address Negotiation(IP Address; IPCP Option 3)
        3. Microsoft DNS and WINS ServerAssignment (Options 129-132)
        4. Nonstandard Option for Subnet-MaskAssignment (Option 144)
      6. Configuring PPP
    11. 10. Frame Relay
      1. Frame Relay Network Overview
      2. The Frame Relay Link Layer
      3. Multiprotocol Encapsulation with RFC 1490
        1. Direct NLPID Encapsulation
        2. SNAP
      4. The Local Management Interface
        1. LMI Operations and Timers
        2. LMI Frame Formats
          1. Information elements
          2. LMI Annex D (ANSI T1.617a Annex D)
          3. LMI Annex A (ITU-T Q.933 Annex A)
      5. Configuring Frame Relay
    12. 11. T1 Troubleshooting
      1. Basic Troubleshooting Tools and Techniques
        1. Loopback Testing
          1. Running loopback tests
        2. Calling for Help
          1. Calling the telco
          2. Before calling your ISP
          3. Before calling your equipment vendor
      2. Troubleshooting Outline
      3. Physical Layer Problems
        1. Red Alarm
          1. Differences between RJ-48, RJ-45, and straight-through Cat 5
        2. Yellow Alarm/RAI
          1. A common culprit: LBO
          2. Other diagnoses
          3. Troubleshooting table
        3. Other Error Conditions
          1. Timing problems (controlled slips)
          2. Bipolar violations (line code violations)
      4. Link Layer Problems
        1. General Link Layer Problems
        2. PPP Problems
        3. Frame Relay Problems
        4. HDLC Problems
    13. A. Access Aggregation with cT1 andISDN PRI
      1. Channelized T1
        1. Signaling on cT1
          1. E&M signaling
          2. Foreign exchange ground start
          3. Foreign exchange loop start
          4. Other methods
        2. Ordering, Provisioning, and Record Keeping for cT1
          1. One- or two-way calling
          2. Telephone numbers, part 1
          3. Telephone numbers, part 2
          4. Signaling
        3. Record Keeping for Later Problems
        4. Configuring Channelized T1
      2. ISDN PRI
        1. ISDN Signaling
        2. Ordering, Provisioning, and Record Keepingfor ISDN
          1. Telephone numbers
          2. Signaling
        3. Record Keeping
        4. Configuring ISDN PRI
    14. B. Multilink PPP
      1. Multilink PPP
        1. Bundling and the MP Architecture
        2. MP Encapsulation
        3. MP Fragmentation and Reassembly
          1. Fragment loss detection
            1. Fragment loss case 1.
          2. MP as a link layer fragmentation mechanism
        4. LCP Options for MP
          1. Maximum Reconstructed Receive Unit (LCP Option 17)
          2. Short Sequence Number header format (LCP Option 18)
          3. Endpoint Discriminator (LCP Option 19)
        5. Bundle Maintenance
          1. Bundle creation
          2. Adding links to an existing bundle
          3. Dropping links
      2. Multi-Chassis MP (MMP)
        1. A Generic Approach to MMP
        2. Nortel Multilink Multinode Bundle Discovery Protocol
          1. Incoming call handling
          2. Discovery message format
          3. Discovery protocol operations
        3. Other Proprietary MMP Solutions
          1. Lucent (Ascend) Multi-Chassis MP (MCMP)
          2. Cisco MMP and the Stack Group Bidding Protocol
    15. C. T1 Performance Monitoring
      1. Collecting Performance Data
        1. Statistics Reported in the PRM
          1. CRC errors
          2. Framing errors
          3. Line code errors
          4. Slip events
        2. Near- and Far-End Statistics
      2. An Overview of the Monitoring Process
      3. Failures, Alarms, and Signaling
        1. Performance Defects
      4. Errors
      5. Performance Data
    16. D. SNMP
      1. RFC 2495: DS1 MIB
        1. Differences from T1.231
        2. The Structure of the MIB
          1. The configuration table
          2. The current statistical table
          3. The interval table
          4. The total table
          5. The far end tables
          6. DS1 trap
      2. RFC 2115: Frame Relay DTE MIB
        1. Structure
          1. DLCMI Table
          2. Circuit table
          3. Error table
          4. Traps
      3. PPP MIBs
        1. RFC 1471: Link Control Protocol MIB
        2. PPP Link Group
          1. Link status table
          2. Link configuration table
        3. RFC 1471: LQR Group
          1. LQR table
          2. LQR configuration table
          3. LQR extensions (optional)
        4. RFC 1471: Test Group
        5. RFC 1473: IP Group
          1. IP table
          2. IP configuration table
    17. E. Cable Pinouts and Serial Information
      1. Introduction to Serial Communications
        1. Serial Line Signaling
        2. Common Serial Signals
      2. High-Speed Serial: V.35
        1. Common V.35 Cabling Problems
      3. RJ-48X
      4. DA-15
    18. F. Reference
      1. Standards Bodies
        1. ANSI Committee T1
        2. International Telecommunications Union
        3. Frame Relay Forum
        4. International Organization for Standardization
        5. Internet Engineering Task Force
        6. Internet Assigned Numbers Authority
        7. Telcordia (Formerly Bellcore)
      2. Physical Layer Standards
        1. DS0 (DDS)
        2. DS1 Standards
        3. Timing
        4. Serial
        5. Channelized T1 Signaling
        6. ISDN
      3. Frame Relay
      4. HDLC
        1. Ethernet Type Codes
      5. PPP
        1. Motivation, Background, and History
        2. Current State-of-the-Art PPP
          1. Network Control Protocols
          2. Multilink PPP
        3. Other PPP Extensions
          1. PPP authentication
      6. SNMP
        1. SNMP Foundations
          1. SNMP Version 2
          2. SNMP Version 3
        2. SNMP MIBs Related to T1
    19. Glossary
    20. Index
    21. Colophon

Product information

  • Title: T1: A Survival Guide
  • Author(s): Matthew Gast
  • Release date: August 2001
  • Publisher(s): O'Reilly Media, Inc.
  • ISBN: 9780596001278