Bandwidth Manager

A development of UserGate Bandwidth Manager is based on a using a well-known algorithm CBWFQ (Class-Based Weighted Fair Queuing). The algorithm provides processing FIFO (First In First Out) packet queues by priority and according a packet classification. A part of the algorithm is WFQ (Weighted Fair Queuing), when FIFO packet queues are processing by priorities and weight (size) of packets. Also the algorithm of Bandwidth Manager includes the Shaper functionality (restriction of a bandwidth for a rule). Shaper also is processing queues by the priority. The other options are: Speed limit (restriction of the transmission speed ) and Time.

The rules for Bandwidth Manager divide into two categories: the first category is a set of rules specifying certain traffic (User rules) and the second is a set of default rules defined for each WAN adapter of the server. Specified in User rules are the following parameters:

  • Priority,
  • Traffic direction (incoming/outgoing),
  • Maximum bandwidth value allowed (Kbps or Mbps),
  • Packet delay (ms),
  • Protocol (TCP/UDP/ICMP),
  • Source IP and port,
  • Destination IP (as an IP/mask) and destination port,
  • Adapter to process the traffic by Bandwidth Manager.

Important note! The “Time Delay” parameter is not included in the user interface. It can be set in the server settings file (config.cfg).

The priority of Bandwidth Manager rule define the FIFO queue when a packet will be placed after the grading. There are 8 priority queues defined: 4 absolute priority queues (HIGH, MEDIUM, NORMAL and LOW) and 4 queues with relative priority.

Manageable traffic speed limiting is provided only for relative priority queues. According to the speed limit specified, a package can be sent to the outgoing buffer, moved to the beginning of the queue (if the parameter “Time Delay” is set) or rejected.

Queues with an absolute priority are intended for privileged traffic processing. If needed, this traffic can fill all the bandwidth of the dedicated Internet channel. There is only one parameter that administrator can use to affect privileged traffic processing – the absolute rule priority.

As a source in the user rule you can specify a certain host as well as an IP address range with a maximum of 256 elements. You can specify a network IP address or a particular host (mask 32) as a destination. Creating a user rule set, please take into account the following:

  • Bandwidth Manager is intended for traffic speed limiting for directions ‘Server - Internet’ and ‘Local Network - Internet’.
  • If a packet matches more than one limiting rule, Bandwidth Manager chooses only the first suitable rule.
  • Bandwidth Manager does not support Dial-Up connections.
A packet, which does not suit any user rules, will be handled by the default rule. There are two parameters specified in the default rule: maximum bandwidth value allowed (Kbps or Mbps) and priority. You should specify the bandwidth value to the Internet connection parameters. The bandwidth specified in the default rule is assumed to be the same for both incoming and outgoing traffic.

Important note! Bandwidth Manager will refuse to operate if the WAN adapter rule is disabled in Bandwidth Manager’s settings.