Table of Contents

Preface. 1. History of the U.S. Telephone Network 1876-1950: Analog Beginnings 1951-1970: The Birth of T-carrier 1970-Present: The Modern Telephone Network. 2. T1 Architectural Overview Telecommunications Puzzle Pieces. 3. Basic Digital Transmission on Telephone Networks Introduction to DS0 Alternate Mark Inversion B8ZS and Clear Channel Capability. 4. Multiplexing and the T-carrier Hierarchy Building the T-carrier Hierarchy with Multiplexing The Original Superframe The Extended Superframe (ESF) Telephone Signaling on T1 Links. 5. Timing, Clocking, and Synchronizationin the T-carrier System A Timing Taxonomy T1 Circuit Timing Slips: When Timing Goes Bad. 6. Mysteries of the CSU/DSU Line Build Out: Moving Between Theory and Practice T1 CSU/DSUs CSU/DSU Configuration Summary of Settings. 7. Connecting the Umbilicus: Getting T1 Connectivity Ordering T1 Installation and Termination Pre-Connection Tasks Trading Packets Post-Connection. 8. High-Level Data Link Control Protocol (HDLC) Introduction to HDLC HDLC Framing Cisco HDLC. 9. PPP Introduction to PPP PPP Logical Link States and State Machines PPP Encapsulation and Framing Link Control Protocol (LCP) PPP Network Control and the IP Control Protocol Configuring PPP. 10. Frame Relay Frame Relay Network Overview The Frame Relay Link Layer Multiprotocol Encapsulation with RFC 1490 The Local Management Interface Configuring Frame Relay. 11. T1 Troubleshooting Basic Troubleshooting Tools and Techniques Troubleshooting Outline Physical Layer Problems Link Layer Problems A. Access Aggregation with cT1 and ISDN PRI B. Multilink PPP C. T1 Performance Monitoring D. SNMP E. Cable Pinouts and Serial Information F. Reference Glossary Index

About the Author

Matthew S. Gast is a former aspiring research physicist who found computer networking too addictive for his own good. He was initially hooked during a summer research program, when he found the Ethernet drop in his dorm room far more interesting than his assigned task of developing monitoring software for a particle accelerator. Upon returning to academic life in the fall, he suffered severe withdrawal symptoms, which he conquered only with the help of a new religion-Unix. He has been connected and sober since that fateful summer. Matthew is currently a Research Fellow at Nokia. His work deals with the intersection of mobility and security, with frequent excursions into routing and cryptography. In the course of daydreaming about changing the world, Matthew has been known to imagine networks that are much less complicated and repetitive to manage. Frequent travels take him away from his Silicon Valley home to a variety of locations throughout the U.S. and Europe, including the occasional visit to the corporate headquarters in Finland. On his last trip to Finland, Matthew crossed the Arctic Circle on a snowmobile in February. Matthew is the coauthor of Network Printing (also published by O'Reilly) as well as several other articles and white papers.