HP-UX IPQoS A.01.00 Administrator's Guide (October 2005)

Introduction
Overview
Chapter 120
• Over the last several years there have been unprecedented increases in network traffic. In
part, this is due to the explosive increases in Internet usage. It is also partly a result of
the tremendous increase in multimedia and wireless applications (applications extremely
susceptible to limits in bandwidth and network capacity).
• Traditional uses of the network now compete with mission critical applications. Thus
there is a greater need for guaranteed communication during unexpected situations, such
as natural disasters and other major emergencies.
• By default, IP networks merely provide “best effort” service to all traffic types. Just
keeping the network up and running is insufficient, because some traffic requires higher
performance.
• Overprovisioning expands and upgrades infrastructure equipment capacity. This
approach tries to keep ahead of peak usage, rather than strategically addressing typical
usage. It can be prohibitively expensive, because the capital investments needed to keep
congestion and queueing delays within reasonable limits during peak times are much
higher than those needed to keep up with average use.
Using DiffServ-compliant nodes (hosts and routers) is an important traffic engineering
technique that helps address these and other problems.
HP-UX IPQoS can help the network support business objectives, while helping minimize the
cost of managing network resources. It helps keep network costs down by using bandwidth
more efficiently and by eliminating the need for overprovisioning as a result of expanding the
usefulness of the existing infrastructure.
HP-UX IPQoS features can help Internet Service Providers (ISPs) and Application Service
Providers (ASPs) offer differentiated levels of network service to customers. Individual
organizations can use HP-UX IPQoS features to prioritize internal traffic.
DiffServ Mechanisms
Generally speaking, IP QoS can be achieved through any mechanism that delivers better than
best effort service to network traffic. The DiffServ model provides IP QoS in networks by
using a defined set of building blocks to build a variety of aggregate behaviors. HP-UX IPQoS
provides controls that enable you to give defined traffic classes differentiated service. It does
this by following specified bandwidth and marking characteristics.
The DiffServ architectural components include traffic classification and traffic
conditioning.