D-Link DFL-1600 - Security Appliance, User Manual

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Figure 10.6. Traffic Grouped By IP Address
Another Simple Groups Example
Consider another situation where the total bandwidth limit for a pipe is 400 bps. If the aim is to
allocate this bandwidth amongst many destination IP addresses so that no single IP address can take
more then 100 bps of bandwidth, the following steps are needed.
• Set the pipe limit, as usual, to be 400 bps.
• Set the Grouping option for the pipe to have the value Destination IP.
• Set the total for the pipe's Group Limits to be 100 bps.
Bandwidth is now allocated on a "first come, first forwarded" basis but no single destination IP
address can ever take more than 100 bps. No matter how many connections are involved the
combined total bandwidth can still not exceed the pipe limit of 400 bps.
Combining Pipe and Group Limit Precedence Values
Let us suppose that grouping is enabled by one of the options such as source IP and some values for
precedences have been specified under Group Limits. How does these combine with values
specified for the corresponding precedences in Pipe Limits?
In this case, the Group Limits precedence value is a guarantee and the Pipe Limits value for the
same precedence is a limit. For example, if traffic is being grouped by source IP and the Group
Limits precedence 5 value is 5 Kbps and the Pipe Limits precedence 5 value is 20 Kbps, then after
the fourth unique source IP (4 x 5 = 20 Kbps) the precedence limit is reached and the guarantees
may no longer be met.
Dynamic Balancing
Instead of specifying a total for Group Limits, the alternative is to enable the Dynamic Balancing
option. This ensures that the available bandwidth is divided equally between all addresses regardless
of how many there are. This is done up to the limit of the pipe.
10.1.7. Pipe Groups Chapter 10. Traffic Management
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