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...

hop Definition 1) In a packet-switching network, a hop is the trip a data packet takes from one router or intermediate point to another in the network. On the Internet (or a network that uses TCP/IP), the number of hops a packet has taken toward its destination (called the "hop count") is kept in the packet header. A packet with an exceedingly large hop count is discarded. 2) Using Cellular Digital Packet Data (CDPD), a hop is a switch to another radio frequency (RF) channel.  

Packet Definition A packet is the unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network. When any file (e-mail message, HTML file, Graphics Interchange Format file, Uniform Resource Locator request, and so forth) is sent from one place to another on the Internet, the Transmission Control Protocol (TCP) layer of TCP/IPdivides the file into "chunks" of an efficient size for routing. Each of these packets is separately numbered and i...

TCP/IP (Transmission Control Protocol/Internet Protocol) TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a suite of communication protocols used to interconnect network devices on the internet. TCP/IP can also be used as a communications protocol in a private network (an intranet or an extranet). The entire internet protocol suite -- a set of rules and procedures -- is commonly referred to as TCP/IP, though others are included in the suite. TCP/IP specifies how data i...