====== Router ======

A //router// (also known as a //packet switch//) is a device that is used to interconnect two or more networks. Its function will be discussed in more detail in Level 2 of your course, but in outline a router is is responsible for forwarding a [[packet]] (//datagram//) from a link in network to a link in another network. The path taken by a packet from [[end-system]] to another [[end-system]], is known as a [[route]]. Routers, are responsible for moving packets closer to their destination and in this sense they work like the post-office sorting offices that are used to deliver mail items. Each packet in the [[Internet]] has a source and destination [[IP address]] which are used by the routers in their forwarding role. 

The incoming and outgoing [[link|links]] to a router need not use the same [[link protocol]]: for example, if you have a [[WiFi]] router at home, then your PC connects to the home network by wireless, but the router probably connects to the your [[broadband]] modem by [[Ethernet]]. 

Routers are "[[Network Layer]]" devices and they implement the [[routing]] part of the [[ip|Internet Protocol]]. Routers are points of possible [[network congestion]] and if packets arrive at a faster rate then the outgoing links, they will need to queue. If the queue is overloaded, packets can be lost. //See also//: [[IP|Internet Protocol]], [[Network Layer]], [[Store and Forward]], [[Queuing Delay]], [[Transmission Delay]], [[Processing Delay]].
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