Chapter 32

Introducing IPQoS (Overview)

IP Quality of Service (IPQoS) enables you to prioritize, control, and gather accounting statistics. Using IPQoS, you can provide consistent levels of service to users of your network. You can also manage traffic to avoid network congestion.

The following is a list of topics in this chapter:

IPQoS Basics

IPQoS enables the Differentiated Services (Diffserv) architecture that is defined by the Differentiated Services Working Group of the Internet Engineering Task Force (IETF). In the Solaris OS, IPQoS is implemented at the IP level of the TCP/IP protocol stack.

What Are Differentiated Services?

By enabling IPQoS, you can provide different levels of network service for selected customers and selected applications. The different levels of service are collectively referred to as differentiated services. The differentiated services that you provide to customers can be based on a structure of service levels that your company offers to its customers. You can also provide differentiated services based on the priorities that are set for applications or users on your network.

Providing quality of service involves the following activities:

Delegating levels of service to different groups, such as customers or departments in an enterprise
Prioritizing network services that are given to particular groups or applications
Discovering and eliminating areas of network bottlenecks and other forms of congestion
Monitoring network performance and providing performance statistics
Regulating bandwidth to and from network resources

IPQoS Features

IPQoS has the following features:

ipqosconf Command-line tool for configuring the QoS policy
Classifier that selects actions, which are based on filters that configure the QoS policy of your organization
Metering module that measures network traffic, in compliance with the Diffserv model
Service differentiation that is based on the ability to mark a packet's IP header with forwarding information
Flow-accounting module that gathers statistics for traffic flows
Statistics gathering for traffic classes, through the UNIX kstat command
Support for SPARC and x86 architecture

Note - The x86 architecture does not support IPQoS on VLANs.
Support for IPv4 and IPv6 addressing
Interoperability with IP Security Architecture (IPsec)
Support for 802.1D user-priority markings for virtual local area networks (VLANs)

Where to Get More Information About Quality-of-Service Theory and Practice

You can find information on differentiated services and quality of service from print and online sources.

Books About Quality of Service

For more information on quality-of-service theory and practice, refer to the following books:

Ferguson, Paul and Geoff Huston. Quality of Service. John Wiley & Sons, Inc., 1998.
Kilkki, Kalevi. Differentiated Services for the Internet. Macmillan Technical Publishing, 1999.

Requests for Comments (RFCs) About Quality of Service

IPQoS conforms to the specifications that are described in the following RFCs and the following Internet drafts:

RFC 2474, Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers - Describes an enhancement to the type of service (ToS) field or DS fields of the IPv4 and IPv6 packet headers to support differentiated services
RFC 2475, An Architecture for Differentiated Services - Provides a detailed description of the organization and modules of the Diffserv architecture
RFC 2597, Assured Forwarding PHB Group - Describes how the assured forwarding (AF) per-hop behavior works.
RFC 2598, An Expedited Forwarding PHB - Describes how the expedited forwarding (EF) per-hop behavior works
Internet-Draft, An Informal Management Model for Diffserv Routers - Presents a model for implementing the Diffserv architecture on routers.