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.
- Review the configuration files for all IPQoS-enabled systems on your network.
- 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) |
- 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.