The letter for today in the Networking ABC's is the letter "Q".  There wasn't a big selection of Q words with regards to the networking world.  I could have went with queue or query, but those didn't have the umph that Quality of Service does.  So, the word for today is the abbreviation for Quality of Service: QoS

"Q" is for QoS

QoS

Pronounced: Kyoo-on-es

The Quality of Service (QoS) level is a means by which network equipment can identify and treat traffic differently based on an identifier.  QoS is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a given data flow.  When the Internet was first deployed it lacked the ability to provide QoS guarantees due to limits in router computing power.  It thus ran at a default QoS level of "best effort".  With the support of QoS within routers, inelastic applications such as streaming multimedia, IP telephony, and video conferencing have come to require a certain minimum level of bandwidth and a certain maximum latency to function.