Providing Differentiated Services on a Router

To provide true differentiated services, you must include a Diffserv-aware router in your network topology, as described in Hardware Strategies for the Diffserv Network. The actual steps for configuring Diffserv on a router and updating that router's files are outside the scope of this guide.

This section gives general steps for coordinating the forwarding information among various IPQoS-enabled systems on the network and the Diffserv router.

How to Configure a Router on an IPQoS-Enabled Network

The next procedure uses as its example the topology in Figure 33-4.

Before You Begin

The next procedure assumes that you have already configured the IPQoS systems on your network by performing the previous tasks in this chapter.

1. Review the configuration files for all IPQoS-enabled systems on your network.
2. Identify each codepoint that is used in the QoS various policies.

   List the codepoints, and the systems and classes, to which the codepoints apply. The next table can illustrate areas where you might have used the same codepoint. This practice is acceptable. However, you should provide other criteria in the IPQoS configuration file, such as a precedence selector, to determine the precedence of identically marked classes.

   For example, for the sample network that is used in the procedures throughout this chapter, you might construct the following codepoint table.

   System	Class	PHB	DS Codepoint
   Goldweb	video	EF	46 (101110)
   Goldweb	goldweb	AF11	10 (001010)
   Userweb	webout	AF12	12 ( 001100)
   BigAPPS	smtp	AF13	14 ( 001110)
   BigAPPS	news	AF18	18 ( 010010)
   BigAPPS	ftp conformant traffic	AF22	20 ( 010100)
   BigAPPS	ftp nonconformant traffic	AF31	26 ( 011010)

3. Add the codepoints from your network's IPQoS configuration files to the appropriate files on the Diffserv router.

   The codepoints that you supply should help to configure the router's Diffserv scheduling mechanism. Refer to the router manufacturer's documentation and web sites for instructions.