Simple Bandwidth Limiting; Fwdfast Rules Bypass Traffic Shaping; Applying A Simple Bandwidth Limit - D-Link NetDefend DFL-210 User Manual

10.1.3. Simple Bandwidth Limiting

It is important to understand that traffic shaping will not work with connection that are established
because of a FwdFast rule in the NetDefendOS IP rule set.
The reason for this is that traffic shaping is implemented based on the NetDefendOS state engine
and a FwdFast IP rule does not set up a connection in the state engine. Packets bypass the state
engine and are forwarded to their destination outside the context of a connection. NetDefendOS
traffic shaping only takes account of traffic flowing through a connection.
Figure 10.2. FwdFast Rules Bypass Traffic Shaping
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
Web Interface
1. Go to Traffic Management > Traffic Shaping > Pipes > Add > Pipe
2. Specify a suitable name for the pipe, for instance std-in
3. Enter 2000 in the Total textbox under Pipe Limits
4. Click OK
Traffic needs to be passed through the pipe and this is done by using the pipe in a Pipe Rule.
We will use the above pipe to limit inbound traffic. This limit will apply to the actual data packets, and not the
connections. In traffic shaping we're interested in the direction that data is being shuffled, not which computer
initiated the connection.
Create a simple rule that allows everything from the inside, going out. We add the pipe that we created to the
return chain. This means that the packets travelling in the return direction of this connection (outside-in) should
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Chapter 10. Traffic Management