QOS-Enabled Networks, 2nd Edition

1The QOS World

Quality of Service (QOS) has always been in a world of its own, but as the technology has been refined and has evolved in recent years, QOS usage has increased to the point where it is now considered a necessary part of network design and operation. As with most technologies, large-scale deployments have led to the technology becoming more mature, and QOS is no exception.

The current trend in the networking world is convergence, abandoning the concept of several separate physical networks in which each one carries specific types of traffic, moving toward a single, common physical network infrastructure. This is old news for the Internet and other service providers, however, a novelty in other realms such as the Data Center. The major business driver associated with this trend is cost reduction: one network carrying traffic and delivering services that previously demanded several separate physical networks requires fewer resources to achieve the same goal.

One of the most striking examples is voice traffic, which was previously supported on circuit-switched networks and is now delivered on the “same common” packet-switched infrastructure. Also, in modern Data Centers the operation of a server writing into the hard drive, the disk, is done using a networking infrastructure that is shared with other traffic types.

The inherent drawback in having a common network is that the road is now the same for different traffic types, which poses the challenge of how to achieve ...