Communication technologies. choose and justify the choice of a particular access control method for a given situation.

CSMA CD: Carries Sense Multiple Access collusion detection is a network contention protocol which has rules on how two devices communicate when transferring data through a data channel simultaneously, CSMA CD is used to improve the CSMA’s performance by terminating as soon as a collision is detected and also reducing the chances of a second collision. CSMA CD is used on most standard networks and they monitor traffic on the line. When two devices attempt to transmit data simultaneously, this will cause collusion on the network. If they are collusion the devices wait a while before trying to transfer data again. CSMA is standards in IEEE 802.3 and ISO 8802.3. If two or three computers in a segment send data at the same time a collisions occur and to avoid this CSMA/CD listens to the Ethernet before sending data making sure other host are not sending data and also listen for the data sent that the data didn’t cause a collision and if a collision is heard the signal is jammed indicating other devices on the internet segments that they has been a collision. Each interface will wait until there is no signal on the channel then it can begin transmitting again and by waiting until carrier ceases before trying to transmit and this process uses carrier sense. Ethernet are classic CSMA/CD access method used in a wired network. When attempting to send data on shared LAN segment, the device would first listen for “carrier sense” to determine if another device is transmitting data “multiple access” and when they is no data transmission, then data is transmitted onto the network. If two stations detect that the network media is not being used both stations send data at the same time, thus a collision occurs “collision detection” the two stations will stop transmitting for a semi random interval before re-transmitting and all Collisions are detected by monitoring signal provided in the physical layer. Switches remove the collision domain so that communication take place between the switch port and the computer connected to the port, if the switch operates in half duplex a collision can occur, when both the switch and the computer try to transmit data at the same time, but in full duplex the switch port and the computer port don’t share the same wires, so that the switch can send data while the attached computer sends data to the switch.

Which do you think is the best method?  Justify your choice

I think CSMA CA is the best method to use as it avoids collusion unlike CSMA CD that only detects collusion in a network and if they are network collusion the collusion has high chances of it happening again as both devices can try to reconnect and transmit data at the same time again. CSMA CA will communicate with the devices and inform them not to transfer any data and in turn having more control on data transmission. we this in mind I would think that both CSMA CA and CSMA CD both need each for a network to work without any problems as they both offer different services which a network need to function without any flaws as collisions that occur in the CSMA/CD are avoided in the CSMA/CA. Depending on the purpose CSMA CD is more suitable for wired networks and CSMA CA is more suitable for wireless networks.

D3 compare and evaluate the effectiveness of the transfer of data over both wireless and wired networks.

Wireless networks allow service providers to deploy high quality data links to deliver internet services, by passing wireline networks, wireless technology offers IT services providers an alternative to traditional copper and cable data transfer. A wireless networks advantage is information sharing and resource sharing between computers. Computers equipped with a wireless card can all communicate in the same wireless device, provided they are in range and a wired LAN needs one port for each computer connected, wireless networks eliminates the need for wiring, provides flexibility for location of  PCs and access point though they offer lower performance, greater complexity and increased expenses. Wireless LAN has many advantages, allowing data capture on site and in real time and spreading of information is improved and runs over TCP which offer a reliable service delivery.

Wired network LAN has a higher data transfer rate than WAN network though WAN has a faster transfer rate to LAN each offer different advantages. WAN are faster , as wireless  are affected by distance which affects the signal strength thus the download speed, while wired network is not affected by distance as long as it reaches the terminal computer. My conclusion is if you require the freedom of accessing the internet in any stations a user would choose a wireless network and for security purposes you may choose LAN network which offers a higher security than WAN and also provides a more reliable internet connection. The limitation with wireless is hidden node problem which disrupts communication in a busy wireless environment and the problem occurs when a station cannot detect the transmission of another station and the use of request to send, clear to send helps to prevent any disruptions.