Network Settings - Bandwidth

Overview

The bandwidth manager is used to shape or prioritize incoming and outgoing network traffic. You can limit and prioitize bandwidth based on IP address, IP address ranges, port, and port ranges.

	Warning!

The bandwidth manager is designed to guarantee a certain speed for either an IP address and/or port on your LAN (or DMZ). The bandwidth manager does not manage traffic to/from the ClarkConnect box itself.

Services

The Bandwidth Monitor service provides hourly bandwidth measurements from our remote system monitors. The service is an excellent tool for monitoring your Internet Service Provider's (ISP) quality of service. This service will monitor your downstream rate, the rate at which you can receive data from an external source (download speed).

How It Works

The bandwidth manager is designed to guarantee a certain speed for either an IP address and/or port on your LAN (or DMZ). The bandwidth manager does not manage traffic to/from the ClarkConnect box itself. To demonstrate how the system works, lets go through a scenario with a voice-over-IP (VoIP) server. We have:

• a 1000 kbit/s upload and download connection to the Internet
• a voice-over-IP (VoIP) server at 192.168.1.80 on our local network
• enabled a bandwidth rule that reserves 500 kbit/s upload and download for the VoIP server

In our example, the network is at first completely congested with web downloads. The VoIP server is idle, so the full 1000 kbit/s is used for the web downloads. In other words, the web downloads are allowed to "borrow" the bandwidth we have reserved for the VoIP server.

Someone in the office then makes an outbound 4-person conference call via the voice-over-IP server. The conference call requires 300 kbit/s and the bandwidth manager will go into action. The lower priority web downloads will get slowed from the maximum 1000 kbit/s to 700 kbit/s. The higher priority conference call will receive its required 300 kbit/s.

Configuration

Bandwidth Rules

A bandwidth management rule contains the following six parameters.

Nickname

The first parameter is an optional nickname you can use to easily identify the rule. Valid nicknames can contain alphanumeric characters (A-z0-9) and optional dashes '-' or underscores '_". Spaces are not allowed.

IP Address/Range

The IP address parameter can contain:

• A single IP address
• A IP address range
• nothing

If this field is left blank, then the bandwidth rule will be used by all IP addresses will. When specifying an IP address range or [Network Notation|network /netmask]], the block of IPs will share the specified bandwidth settings. For example, 192.168.0.1/24 with 500 kbit/s download means the entire 192.168.0.x network will not be able to use more that 500 kbit/s of download bandwidth. All systems on the 192.168.0.x must share this bandwidth.

Port/Range

The port parameter is used to apply a bandwidth rule to a particular service. For instance, you can limit web traffic by specifying port 80. If the port is left empty, then all ports will be affected. You may also specify a colon-delimited port range. For instance, 5000:5010 would impact all the ports between 5000 and 5010.

Priority

Priority provides a mechanism to prioritize traffic when all bandwidth rules are at capacity. Higher priority traffic will be given preference over lower priority traffic. There are 7 priority levels, 1 - 7, where 1 is the highest priority. By default, traffic that is not matched by a bandwidth rule will be assigned the lowest priority.

Upload

The upload rate in kilobits per second. If left empty, the upload rate will be unlimited.

Download

The download rate in kilobits per second. If left empty, the download rate will be unlimited. Note: If both upload and download are left empty, then the rule will be invalid.

Peer-to-Peer Bandwidth Rules

In order to manage peer-to-peer traffic, make sure you have the Peer-to-Peer module installed.

Configuring bandwidth control for peer-to-peer is similar to creating a regular bandwidth rule. However, you need to specify the peer-to-peer network instead of the IP address and port.

Units - kbit/s, kbps, Mbps, and Other Confusion Notation

Depending on where you are and who you are talking too, there are different measurement units used for bandwidth. Here are some tips to help with converting from one unit to another -- capitalization is important:

Conversion tips:

• Mega is 1000 times larger than kilo
• A byte is 8 times larger than a bit

Examples:

• 1 Megabit per second is approximately 1000 kilobits per second
• 1 Megabyte per second is approximately 8000 kilobits per second

Links

• Linux Advanced Routing and Traffic Control
• HTB Queueing