|Fundamentals of T-1/T-3|
Course DescriptionA Comprehensive Overview of T-1/T-3 Networks, Technologies, and Services
In-class DemonstrationsClass demonstrations are designed to solidify concepts presented in class by showing how they are implemented in practice. Accordingly, demonstrations are woven throughout the presentation. The emphasis is on showing the physical form these concepts take in real-world equipment. If you would like us to use your equipment instead of our own, we will be pleased to do so.
· Examine a DSU/CSU to find out how its connectors are used
Students are encouraged to bring their own equipment and/or manuals
to class in order to see how their documentation and equipment relates
to the principles presented in class. Students are welcome to experiment
with the class equipment during breaks, lunch or after class.
1. An Overview of the T-carrier systemWe'll explore the development of the T-carrier hierarchy and its value to users and carriers. Examine the basic components of a T1 digital transmission system, and discover the potential benefits and risks associated with this durable technology.
A. The T-carrier hierarchy
2. Understanding T-1 TechnologyIn this unit we categorize the components of a T-1 carrier system. We note the shape of the DS-1 signal and what it can do. We use a unique method of explanation to help students absorb difficult concepts such as onesā density, D4 and Extended Superframe. The ways in which a T-1 can be channelized or fractionalized are discussed using the same technique. Finally, we explain how robbed-bit signaling provides the control necessary for telephone use.
A. Analog versus digital signals: pros and cons
B. Why go digital?
C. Where T-carriers fit in the North American Switching Hierarchy
1. Subscriber Loop Carrier systems
D. Components of a T-carrier system
E. Pulse Code Modulation, frame rates and aliasing
F. Maintaining onesā density: AMI versus B8ZS
G. DS-1 frame formats: D4 and ESF (54016 and T1.403)
1. Facility Data Links
2. CRC-6 Error Detection
H. E-carriers and how they are organized (optional)
I. How T-1s are channelized and fractionalized
3. The T-3 ProtocolsT-3ās 44.736 Mbps speed is a natural evolutionary step from the T-1 rate. Since many DS-1s are multiplexed up to the DS-3 level at telephone company central offices, understanding the DS-3 level of the hierarchy is useful whether or not you plan to use it directly.
A. Components of a T-3 carrier system
4. Timing and SignalingIn this unit we explain how T-carrier systems are timed, who supplies the timing, who must take it and how to minimize timing problems. While timing and synchronization are closely related, they are not the same thing, and this unit explains the differences between them. Clock quality within the telephone company can vary, so we will explain the different levels of clock quality and what you need to know in order to maintain a stable system.
A. Timing and synchronization: not the same!
B. The Four Kinds of Timing
C. Stratum levels
D. Slips and how to minimize them
E. How to evaluate carrier clocking schemes
F. Subscriber loop and interoffice (CCIS/SS7) signaling
1. In-band and out-of-band