CSMA/CD - Carrier Sense Multiple Access / Collision Detection Short for Carrier Sense Multiple Access / Collision Detection, a set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously (called a collision). Standard Ethernet networks use CSMA/CD to physically monitor the traffic on the line at participating stations. If no transmission is taking place at the time, the particular station can transmit. If two stations attempt to transmit si...

Multiplexing Definition Multiplexing (or muxing) is a way of sending multiple signals or streams of information over a communications link at the same time in the form of a single, complex signal; the receiver recovers the separate signals, a process called demultiplexing (or demuxing). Networks use multiplexing for two reasons: To make it possible for any network device to talk to any other network device without having to dedicate a connection for each pair. This requires shared media;...

QoS (quality of service) Definition Quality of service (QoS) refers to any technology that manages data traffic to reduce packet loss, latency and jitter on the network. QoS controls and manages network resources by setting priorities for specific types of data on the network. Enterprise networks need to provide predictable and measureable services as applications -- such as voice, video and delay-sensitive data -- traverse the network. Organizations use QoS to meet the traffic requirements ...

forward error correction (FEC) Forward error correction (FEC) is a method of obtaining error control in data transmission in which the source (transmitter) sends redundant data and the destination (receiver) recognizes only the portion of the data that contains no apparent errors. Because FEC does not require handshaking between the source and the destination, it can be used for broadcasting of data to many destinations simultaneously from a single source. In the simplest form of FEC, ea...

IPsec (Internet Protocol Security) IPsec, also known as the Internet Protocol Security or IP Security protocol, defines the architecture for security services for IP network traffic. IPsec describes the framework for providing security at the IP layer, as well as the suite of protocols designed to provide that security, through authentication and encryption of IP network packets. Also included in IPsec are protocols that define the cryptographic algorithms used to encrypt, decrypt and authentic...

CHAP (Challenge-Handshake Authentication Protocol) CHAP (Challenge-Handshake Authentication Protocol) is a more secure procedure for connecting to a system than the Password Authentication Procedure (PAP). Here's how CHAP works: After the link is made, the server sends a challenge message to the connection requestor. The requestor responds with a value obtained by using a one-way hash function. The server checks the response by comparing it its own calculation of...

Packet Loss Definition Packet loss is the failure of one or more transmitted packets to arrive at their destination. This event can cause noticeable effects in all types of digital communications. The effects of packet loss: In data, packet loss produces errors. In videoconference environments it can create jitter. In pure audio communications, such as VoIP, it can cause jitter and frequent gaps in received speech. In the worst cases, packet loss can cause severe mutila...