- 150 -
13. If you want to delete the trunk configuration, please select the trunk and press to delete.
Note: This screen also lets you use the L switch to toggle the ports, as described under Section 4.3.5.3
“Hiding or Displaying the Port Column”.
5.15 Setting Quality of Service Parameters

5.15.1 Basic concept

5.15.1.1 QoS model
Quality of service is an all-encompassing term for which different people have different interpretations.
In general, the approach to quality of service described here assumes that we do not know the offered
traffic pattern. We also assume that the incoming traffic is not policed or shaped. Furthermore, we
assume that the network manager knows his applications, such as voice, file transfer, or web browsing,
and their relative importance. The manager can then subdivide the applications into classes and set up
a service contract with each. The contract may consist of bandwidth or latency assurances per class.
Sometimes it may even reflect an estimate of the traffic mix offered to the Switch. As an added bonus,
although we do not assume anything about the arrival pattern, if the incoming traffic is policed or
shaped, we may be able to provide additional assurances about our switch’s performance.
The two tables below show examples of QoS applications with eight and four transmission priorities for
gigabit ports and megabit ports..

TABLE 5- 2 GIGABIT PORT QOS CLASS

Sample Application Class of
Gigabit Port
Bandwidth Partitions
(Default and User
Configurable)
Low Drop Subclass High Drop Subclass
P7 (Highest) 25% Control information
P6 25% Phone calls, circuit
emulation
Training video, other
multimedia
P5 12.5% Interactive activities Non-critical
interactive activities
P4 12.5% Web business Non-critical
interactive activities
P3 6.25% File backups