dmm™

The Difference of CSMA/CD and CSMA/CA

CSMA/CD - Ethernet (wired) networks Carrier Sensing Multiple Access / Collidision Detection, this is the full acronym of the well-known medium accessprotocol that made Ethernet based LAN'S so spread and efficient. While CSMA/CA - 802.11 Wireless LAN Collision Detection cannot be used for wireless environments for 3 main reasons:- Wireless communications are in half-duplex. If we had an antenna to listen and another to transmit we should be able to detect a collision while we transmit. This time the medium is the air and the power of the transmitting antenna willconfuse the receiving one thus making detection almost impossible.

CSMA/CD vs CSMA/CA
CSMA/CD is used on Ethernet networks (or similar). We can detect any collisions because all the receivers are on the same wire as the transmitters.
CSMA/CA cannot do this as the receivers may suffer a collision due to the hidden terminal problem.
CSMA/CD senses the medium and then immediately transmits. If it detects a collision, it backs off for a random period.
CSMA/CA senses the medium, then waits a random number of slots, then senses again. This avoids the problem of all stations waiting until the medium is free, and then immediately all transmitting (i.e. colliding).
CSMA/CA therefore introduces slight delays, because of this extra random wait time.
We can detect collisions on both by means of listening CSMA/CD, and by the lack of an ACK in CSMA/CA.

Difference of Client and Server

A Servers are often dedicated, meaning that they perform no other tasks besides their server tasks. A computer or device on a network that manages network resources. Typically, a client is an application that runs on a personal computer or workstation and relies on a server to perform some operations.


Characteristics of a client
Request sender is known as client
Initiates requests
Waits for and receives replies.
Usually connects to a small number of servers at one time
Typically interacts directly with end-users using a graphical user interface

Characteristics of a server
Receiver of request which is send by client is known as server
Passive (slave)
Waits for requests from clients
Upon receipt of requests, processes them and then serves replies
Usually accepts connections from a large number of clients
Typically does not interact directly with end-users