3Com CoreBuilder 3500, Руководство по внедрению, Страница: 495 / 592

QoS Controls 495
This next example illustrates how TCP one-way-filtering can be effective.
Figure 85 shows the same situation, but with TCP drop control enabled to
filter only those packets with the SYN=1 and ACK=0 signature.
Figure 85 QoS Control Action (Drop Control Enabled)
In this example, any attempt by a client on an End User network to
establish a TCP connection to a server on the Admin network still fails,
but it is now possible for clients on the Admin network to establish TCP
connections to servers on any network without restriction.
Setting the QoS
Timer Control
The QoS Timer option lets you configure a QoS session to take effect
during a predefined time period by setting the start and end times for the
specific control. Setting the start and end times is similar to using a VCR
to record programs.
The default setting for the timer control is no (no timer control). QoS
controlled classifiers are in effect all the time when timer control is not
enabled.
■
Starting and ending days use the following syntax:
mm–dd
For example, to enter a date of May 20 you would enter: 05–20
■
Starting and ending times use the following syntax:
hh:mm
For example, to enter a time of 10 o’clock in the morning you would
enter: 10:00
QoS Classifier:
Source IP:
0.0.0.0
Destination IP:
10.1.1.0
QoS Control Action:
Drop only
(SYN=1, ACK=0)
10.1.1.254 10.1.2.254
Admin
End-user
network