Editing Packet-switched network

A '''packet-switched network''' means that [[data]] [[transmit]]ted over the [[network]] is split up into small chunks, or "[[packet]]s." In packet-switched systems, the [[information]] is broken down into smaller pieces called “[[packet]]s” using a [[digital]] process. Each [[packet]] contains a small part of the [[message content]] along with [[call-identifying information]] called a “[[header]]” that indicates the [[origination]] and [[destination]] points of the [[information]].  

The packet-switched mode is the signal transmission technology used in all 
[[Internet]] communications. Packet switching is considered a more efficient use of a [[network]] than [[circuit switching]] because the same line can be used for multiple communications simultaneously. 

Unlike "circuit-switched" networks such as the [[public switched telephone network]] ([[PSTN]]), a packet-switched network is "connectionless." In other words, a dedicated end-to-end transmission path (or circuit) does not need to be opened for each [[transmission]]. Rather, each [[router]] calculates the best [[routing]] for a [[packet]] at a particular moment in time, given current [[traffic]] patterns, and sends the [[packet]] to the next [[router]]. Thus, even two [[packet]]s from the same [[message]] may not travel the same physical path through the [[network]]. This mechanism is referred to as "[[dynamic routing]]."

When [[packet]]s arrive at the destination point, they must be reassembled, and [[packet]]s that do not arrive for whatever reason must generally be re-sent. This system allows [[network]] resources to be used more efficiently, as many different communications can be [[routed]] simultaneously over the same [[transmission]] facilities. On the other hand, the inability of the sending [[computer]] under such a "best effort"<ref>In a ''best effort'' delivery system, [[router]]s are designed to "drop" [[packet]]s when [[traffic]] reaches a certain level. These dropped [[packet]]s must be resent, which to the [[end user]] is manifested in the form of delay in receiving the [[transmission]].</ref> [[routing system]] to ensure that sufficient [[bandwidth]] will be available between the two points creates difficulties for services that require constant [[transmission rate]]s, such as [[streaming]] video and voice applications.

== References ==
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[[Category:Technology]]
[[Category:Internet]]