Simple Bandwidth Limiting - D-Link DFL-1660 User Manual

10.1.3. Simple Bandwidth Limiting

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.
10.1.3. Simple Bandwidth Limiting
The simplest use of pipes is for bandwidth limiting. This is also a scenario that does not require
much planning. The example that follows applies a bandwidth limit to inbound traffic only. This is
the direction most likely to cause problems for Internet connections.
Example 10.1. Applying a Simple Bandwidth Limit
Begin with creating a simple pipe that limits all traffic that gets passed through it to 2 megabits per second,
regardless of what traffic it is.
Command-Line Interface
gw-world:/> add Pipe std-in LimitKbpsTotal=2000
Figure 10.2. FwdFast Rules Bypass Traffic Shaping
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Chapter 10. Traffic Management