User guide

160 CHAPTER 8: PRIORITIZING NETWORK TRAFFIC
Service levels enable easy identification of end-to-end treatment of
traffic. If the example was to be configured appropriately on the devices
throughout the network, it would be possible to say that database traffic
is treated as business critical throughout the network.
Settings within a service level may vary from device to device depending
upon the device’s capabilities. One device, for example, may have four
queues whilst another device may have two. As a result, a particular
service level on one device may put the traffic in queue 3 while on
another device it may be queue 1. However, identifying the service levels
by name simplifies the understanding of the configuration.
Configuring the
Network for
End-to-end Traffic
Prioritization
When some devices in a network are complex classification devices and
other devices are simple classification devices, it is necessary to apply
configurations in such a way that the markings applied by the complex
classification devices are treated appropriately by the simple classification
devices.
In the previous example it was possible to specify that each service level
marked its traffic with a DiffServ codepoint, assuming that the device in
question was a complex classification device. The DiffServ codepoints can
be seen in Ta bl e 15
.
Table 15 DiffServ Codepoints
The DiffServ codepoints chosen in the table above are taken from the
recommended values from RFC2474 and RFC3246.
The Blocked Service Level does not require a DiffServ codepoint value as
the traffic is dropped anyway which makes marking the traffic
unnecessary.
In order for devices to be able to provide suitable prioritization when they
are not capable of identifying the types of traffic, it is possible to
configure the devices to identify the traffic by their DiffServ codepoint.
Service Level DiffServ Codepoint
Business Critical Service Level 16
CEO’s Service Level 24
Voice Service Level 46
All Other Traffic Service Level 0
3Com Network Administrator for HP OpenView.book Page 160 Wednesday, November 12, 2003 2:33 PM