Metro Area Networking
Detailing the technological challenges and opportunities in a lucid, humorous prose, this book lays bare the tricks and traps awaiting service providers in the metro area space.
TABLE OF CONTENTS Metro Area Networking
Up the Stack: The Ethernet Physical Layer
Over the years since Ethernet s arrival on the LAN scene, it has gone through a series of metamorphoses. Today, it still operates at a range of bandwidth levels and is found in a variety of applications ranging from the local area to limited long-haul deployments. In the section that follows, we discuss the various flavors of Ethernet, focusing on the physical layer. We begin with the venerable Base5.
10Base5
10Base5 was the first 10 Mbps Ethernet protocol. It operated over 10-millimeter coaxial cable and was commonly referred to as Thicknet because of the diameter of the cable. A word about nomenclature: 10Base5 represents a naming convention crafted during the creation of the 802 Committee standards. The 10 refers to 10 Mbps or the transmission speed, Base means that the transmission is digital baseband, and 5 refers to the 500-meter maximum segment length. Other names in the series are similar.
The original coax used in Thicknet installations was marked every 2.5 meters to indicate the point at which 10Base65 transceivers could be connected to the shared medium. They did not have to be connected at every 2.5-meter interval, but they did have to be placed at distances that were multiples of 2.5 meters. This separation served to minimize signal reflections that could degrade the quality of signals transmitted over the segment. Ten-millimeter Thicknet cable was typically bright yellow, with black indicator bands every 2.5 meters.
A Touch of Transylvania
In 10Base5 networks, transceivers...
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