TABLE OF CONTENTS A typical enterprise network topology has multiple local area networks (LANs) connected by bridges or Layer 2 switches. Many times the different LANs are all of one type, typically wired Ethernet, but that is changing. Wireless networks are entering these hallowed grounds. Furthermore, today's networks are converging into a unique network infrastructure that is expected to carry data in the form of voice, video, and mission critical applications. These applications require a certain amount of bandwidth in order to provide the end-user with a quality product, and that's where Quality of Service comes into play. The term "Quality of Service" (QoS) refers to the quality of network services. It is sort of an umbrella term for all the related technologies that are put in place with the objective of providing QoS, so as to supply better network services in order to satisfy network applications' bandwidth needs. QoS is not related to a specific technology or network topology, but transparently crosses all networks IP, Frame Relay, ATM, Ethernet, cellular, and Wi-Fi.
With the help of "Quality of Service" or "QoS" technologies, networks (and network managers) can give priority to certain data, users, and/or applications. This is typically accomplished via bandwidth management techniques that allow specific types of application to have specified bandwidth and delivery requirements satisfied. In a non-QoS-enabled network all data packets generally receive the same "best effort" service.
When QoS mechanisms are in place, an...
