Pipe Rules Determine Pipe Usage - D-Link NetDefendOS User Manual

Chapter 10: Traffic Management
Figure 10.1. Pipe Rules Determine Pipe Usage
The pipes that are to be used are specified in a pipe list. If only one pipe is specified then that is
the pipe whose characteristics will be applied to the traffic. If a series of pipes are specified then
these will form a Chain of pipes through which traffic will pass. A chain can be made up of a
maximum of 8 pipes.
Explicitly Excluding Traffic from Shaping
If no pipe is specified in a pipe rule list then traffic that triggers the rule will not flow through any
pipe. It also means that the triggering traffic will not be subject to any other matching pipe rules
that might be found later in the rule set.
This provides a means to explicitly exclude particular traffic from traffic shaping. Such rules are
not absolutely necessary but if placed at the beginning of the pipe rule set, they can guard
against accidental traffic shaping by later rules.
Pipes Will Not Work With FwdFast IP Rules
It is important to understand that traffic shaping will not work with traffic that is flows as a result
of triggering a FwdFast IP rule in the NetDefendOS IP rule sets.
The reason for this is that traffic shaping is implemented by using the NetDefendOS state engine
which is the subsystem that deals with the tracking of connections. FwdFast IP rules do not set
up a connection in the state engine. Instead, packets are considered not to be part of a
connection and are forwarded individually to their destination, bypassing the state engine.
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