tailieunhanh - CompTIA Network+ Certification Study Guide part 13

CompTIA’s Network+ certification Study Guide part 13 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 106 CHAPTER 3 Network Devices HEAD OF THE CLASS. What Do I Need to Know About Token Ring for the Network Exam Although an aging technology Token Ring is still supported on a great many networks. The reason is that the mainframes used to be the rulers of the world and many companies relied on them to store their data. They were accessed by dumb terminals that ran on UNIX. Many of those older networks ran Token Ring. As dumb terminals were replaced by PCs and the networks were migrated to Ethernet the mainframes stood firmly in place. What some may not know is that because it was so expensive to replace a network card on a mainframe it was often cheaper to just get a router with a Token Ring interface as well as an Ethernet one so many Token Ring networks exist as of this day So what exactly do you need to know about Token Ring Well it is important to know what it is not . Ethernet. Do not let questions trip you up. You could be asked about which type of hardware is used to connect your networking interface card NIC to your PC and MAU on an Ethernet network . Token Ring and Ethernet hardware are completely incompatible they are completely two different standards. You would need some form of gateway to translate one technology to another for example as in the scenario mentioned earlier when the router was used to connect the two dissimilar networks together. Figure shows an example of this in action. In our example the Windows Server system has two NICs installed one Ethernet one Token Ring. The Routing and Remote Access Service RRAS is installed and functioning. This server is acting as a router and connecting two different network segments together. The Token Ring NIC is connected to an MAU with two PCs attached to it. The Ethernet NIC is connected to a hub with two PCs also connected to it. Although both technologies coexist do not think that they are interchangeable - they are not. Ethernet is Ethernet and Token Ring is Token Ring. Be careful. FIGURE Two .