Wireless Communication - Essay Example

Running Header: WIRLESS Wireless Communication Mesh Topology Mesh topology or mesh network is a network topology in which devices are connected with many redundant interconnections between network nodes. In a true mesh topology every node has a connection to every other node in the network. Advantages and Disadvantages As all nodes are interconnected with each other hence mesh topology yields greatest amount of redundancy, so in the event that one of those nodes fails, network traffic can be directed to any of the other nodes.

Since for full mesh network topology every node must has a circuit connecting it to every other node in a network hence it is a very expensive to implement. Ring Topology In ring topology all devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. Advantages and Disadvantages Ring topologies are relatively expensive and difficult to install, but they offer high bandwidth and can span over large distances.

Mesh Star Topology Fig. 1 Star, Bus, Ring & In star topology all devices are connected to a Mesh Topologies central hub. Advantages and Disadvantages Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub. The above mentioned topologies are shown in fig.

1 on page 2. Ethernet A most widely implemented local-area network (LAN) architecture developed by Xerox Corporation in cooperation with DEC and Intel in 1976 is termed as Ethernet. It uses a bus or star topology (as shown in fig. 1) and supports data transfer rates of 10 Mbps. A newer version of Ethernet called 100Base-T supports data transfer rates of 100 Mbps while the latest version, Gigabit Ethernet has data transfer rates of 1 gigabit (1,000 megabits) per second. The Ethernet specification served as the basis for the IEEE 802.

3 standard, which specifies the physical and lower software layers. Ethernet uses the Carrier Sense with Multiple Accesses with Collision Detect (CSMA/CD) access method to handle simultaneous demands. Token Ring Token ring is a type of computer network developed by IBM, in which all the computers are arranged (schematically) in a circle using ring topology. A token, which Fig. 2 Token Ring Network is a special bit pattern, travels around the circle. To send a message, a computer catches the token, attaches a message to it, and then lets it continues to travel around the network.

Token transmission does not depend on CSMA/CD. Instead, all token ring hardware coordinates among all connected computers to insure that transmission is passed to each computer in turn. FDDI Fiber Distributed Data Interface (FDDI) is a set of American National Standards Institute (ANSI) and ISO standards for data transmission on fiber optic lines in a local area network (LAN) that can extend in range up to 200 km (124 miles). The FDD protocol is based on the Token Ring protocol. In addition to being large geographically, an FDDI local area network can support thousands of users.

FDDI is frequently used on the backbone for a wide area network (WAN). An FDDI network contains two token rings, one for possible backup in case the one for possible backup in case the primary ring fails. The primary ring offers up to 100 Mbps capacity. If the secondary ring is not needed for backup, it can also carry data, extending capacity to 200 Mbps. The single ring can extend the maximum distance; a dual ring can extend 100 km (62 miles). Wireless Networks A network which is created through the connection of wireless access points installed at each network users locale is called wireless network.

It can has either star or mesh or mesh topology. If all network users have access through an access point then such wireless network works in star topology. If in wireless network each network user is also a provider, forwarding data to the next node then such wireless network operates in mesh network topology. In wireless mesh network the infrastructure is decentralized and simplified because each node need only has to transmit for the next node. TCP/IP The TCP/IP layering model which is also called Internet Layering Model or the Internet Reference Model contains five layers as illustrated in fig. 3. Although TCP/IP reference model corresponds to layers of the OSI reference model, the OSI layering scheme does not have a layer that corresponds to TCP/IP’s Internet Layer .

Fig. 3 Reference Comer, D. E. (1997). Computer Networks and Internets. Upper Saddle River, New Jersey: Prentice Hall Tanenbaum, A. S. (1999). Computer Networks. Upper Saddle River, New Jersey: Prentice Hall