Describe the primary network architectures, systems, applications and utilities that allow networks to provide their services.

Primary network architectures , systems , applications and utilities By Local Area Network (LAN ) Considerations LAN communications design composes of several technical considerations as following network topology (star , mesh , or bus etc transmission media (wireless or wire line /cable transmission speed (bit rate etc Four Elements of Local Area Network (LAN ) Design Local Area Network (LAN ) design must adopt four elements as following Functionality LAN must provide users with acceptable speed and reliability Scalability LAN design must anticipate the growth in the number of users in the future without performing any

major changes to the overall design Adaptability LAN must be capable of employing future technologies Manageability LAN must employ network monitoring and management in to provide better services to clients (Harris , 2000 Network Protocol : Token Ring and Ethernet Ethernet Most widely used protocol in computer networks Runs in an access method called CSMA /CD (Carrier Sense Multiple Access /Collision Detection

Why Employ Ethernet Network Characteristics Ethernet is a shared access medium all computers have equal access to the network at the same time Token Ring is single access , which means that only one token exists in data transmission The method thus only allow one computer to use the LAN

Physical Media Ethernet can use many kinds of transmission media such as twisted pairs , coaxial , fiber optic cable etc no-collision between two computers that send data simultaneously Token Ring Only works best in Star Topology when using twisted pair cable and fiber optic How to convert into Ethernet No converter needed It means that conversion between Ethernet network and Token Ring network to communicate between each other A conversion process must occur between the two topologies , since they both use different signaling types , frame structures , and frame sizes There are two methods to accomplish this 'conversion bridging , and routing Bridging -------- Bridging is a method of communicating between devices at OSI layer 2 , the data link layer . A bridge connects two networks together and acts as a traffic director . If traffic is destined to the other network , the bridge allows the traffic to pass . If the traffic is local to a single network , the bridge does not pass the traffic unnecessarily to the other connected network . The bridge makes this determination based on the Media Access Control (MAC ) address of the workstations on the network . The bridge keeps an updated list of everyone active on the network , and uses this list to direct traffic from one network to another . This method of operation makes the network appear as a single logical network , since the only separation of traffic from one network to another is done at the MAC address level . There are many bridge manufacturers and bridge types on the market . The newest version of this bridging technology is called a DLC Switch or LAN Switch . These switches have a much higher port density than the older two or three port bridges , allowing for much more flexibility and network segmentation Routing ------- The second method of 'converting ' from Ethernet to Token...