Bandwidth Settings

Click Bandwidth in the right pane to open the Bandwidth Control Settings screen.

Figure 4-20: The Bandwidth Control Settings screen.

Use this screen to specify whether to enable bandwidth rules and a dynamic bandwidth shaper. The screen also shows which bandwidth rules are currently in use. You can add, remove, or edit entries from the list. If you click Edit, the Edit Bandwidth Rule screen opens.

The Bandwidth Shaper attempts to do the following:

  • Dynamically condition traffic for low latency, and for fast uploads and downloads.

  • Maintain low latency for interactive traffic at all times. This means that downloading or uploading files should not disturb SSH or even telnet.

  • Allow 'surfing' at reasonable speeds while uploading or downloading. Even though httpi is 'bulk' traffic, other traffic should not drown it out.

  • Make sure uploads don't harm downloads, and vice versa. This is a much observed phenomenon where outbound traffic simply destroys download speed.

  • The reason that uploads, downloads and ssh hurt each other is the presence of large queues in many typical internet connections like cable or DSL modems.

Note: The bandwidth shaping Web interface is a front for files that are used by a script that perform advanced bandwidth shaping based on Class Based Queueing (CBQ).

Custom Bandwidth

Only advanced users should change the options on this screen.

Figure 4-21: The Custom Bandwidth screen.

Select an interface and then you can Edit the associated rule in the list. You can also click Add to open the Bandwidth Rule screen, where you can enter the rule you want to use.

Edit Bandwidth Rule

Use this screen to modify or add an existing bandwidth rule. Only advanced users should use this screen.

Figure 4-22: The Edit Bandwidth Rule screen.

You can specify the following options for the selected bandwidth rule:

  • Interface: The interface you want to control traffic on.

  • Bandwidth: The physical bandwidth of the device, e.g. for Ethernet 10Mbit or for fast Ethernet 100Mbit.

  • Rate: Select 64Kbit, 128Kbit, 256Kbit, 512Kbit, 768Kbit, 1Mbit, 5Mbit, 10Mbit, 100Mbit, or 1000Mbit.

  • Weight: A tuning parameter that should be proportional to the rate parameter. As a rule of thumb, use weight~=rate/10.

  • Priority: The priority of class traffic. The higher the number, the lesser the priority.

  • Source Rule:

  • [[saddr[/prefix]][:port[/mask]],][daddr[/prefix]][:port[/mask]]

These parameters make up "u32" filter rules that select traffic for each of the classes. You can use multiple RULE fields per configuration. The optional port mask should only be used by advanced users who understand how the u32 filter works.



selects traffic going to port 80 in network


selects traffic going to any port on single host


selects traffic going to ports 20 and 21 on host


selects traffic going from anywhere on port 50 to

port 5000 in network


selects traffic going from port 80 of single host

After you make changes to this screen, click Update to apply and save those settings. Note that only the changes you made on the current screen are applied and saved. You are returned to the Bandwidth Settings screen.


Adding HTB Class