What is Protocol stack?
[[File:OSI_Model_v1.svg|thumb|Protocol stack of the [[OSI model]]]] A '''protocol stack''' is a part of an [[operating system]] (OS) or device that is used to [[Communication|communicate]] with other things. Computers communicate in many ways. A [[mobile phone]] contains several protocol stacks. There are protocol stacks in a mobile phone for handling voice calls, for [[Bluetooth]], for [[Wi-Fi]], and for [[USB]]. There is a protocol stack used when reading a webpage on [[Wikipedia]]. Sometimes the protocol stacks work together. An example of this is when a person uses a Bluetooth headset for a voice call. One stack is used for the phone to communicate with the headset. Another stack is used to make the voice call. The Bluetooth headset or earbud has its own bluetooth protocol stack. The protocol stacks are used to send and receive information. Each layer of the protocol stack handles a different part of the communication. There is a protocol stack with many different layers that are used to send and receive data. When two things communicate with each other in a standard manner, this is known as a [[protocol]]. Some layers within the protocol stack will work on ''reliability.'' They will send a message again if the first message was lost in communication. Some layers will provide ''compatibility.'' They will let data to be communicated in different ways, like over [[Wi-Fi]] or over a network wire, but the layers above don't need to know what way is being used. And whether wifi or wired - those layers don't need to know if it is carrying text in a wikipedia page, or perhaps the data in a picture. They let different types of data to be communicated in a standard manner. Layers often handle a series of chunks of data. Some layers split the data into smaller chunks when sending it. This is called ''fragmentation.'' When the data is received, another layer puts the smaller chunks back together to form larger chunks or [[Streaming media|media streams]]. This is called ''reassembly''. Some