|  | 7.1 |
| 10-Mbps and 100-Mbps Ethernet
|  | 7.1.9 |
| Fast Ethernet architecture
Fast Ethernet links generally consist of a connection between a station and a hub or switch. Hubs are considered multi-port repeaters and switches are considered multi-port bridges. These are subject to the 100 m UTP media distance limitation. A Class I repeater may introduce up to 140 bit-times of latency. Any repeater that changes between one Ethernet implementation and another is a Class I repeater. A Class II repeater may only introduce a maximum of 92 bit-times latency. Because of the reduced latency it is possible to have two Class II repeaters in series, but only if the cable between them is very short. As with 10 Mbps versions, it is possible to modify some of the architecture rules for 100 Mbps versions. However there is virtually no allowance for additional delay. Modification of the architecture rules is strongly discouraged for 100BASE-TX. 100BASE-TX cable between Class II repeaters may not exceed 5 meters. Links operating in half duplex are not uncommon to find in Fast Ethernet. However, half duplex is undesirable because the signaling scheme is inherently full duplex. Figure shows architecture configuration cable distances. 100BASE-TX links can have unrepeated distances up to 100 m. The widespread introduction of switches has made this distance limitation less important. If workstations are located within 100 m of a switch, the 100 m distance starts over at the switch. Since most Fast Ethernet is switched, these are the practical limits between devices.
|  | Lab Activity
Lab Exercise: Introduction to Fluke Network Inspector This lab is a tutorial demonstrating how to use the Fluke Networks Network Inspector (NI) to discover and analyze network devices within a broadcast domain.
|  | Lab Activity
Lab Exercise: Introduction to Fluke Protocol Inspector This lab is a tutorial demonstrating how to use the Fluke Networks Protocol Inspector to analyze network traffic and data frames.
|  | Interactive Media Activity
Drag and Drop: Fast Ethernet Architecture After completing this activity, the student will understand the architecture of Fast Ethernet. Interactive Media Activity 7.1.9 is located in the CCNA 3.0 Bridge 1 Activities and Quizzes file. The Activities and Quizzes file can be downloaded in the Course Material section of your class homepage.
Web Links
Ethernet Design Rules http://www.bostontech.net/assets/files/ articles/TechBrief1_P1.pdf