Introduction

Overview

•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.

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Chapter 1