Administrator's Guide - Kerio Software Archive

Chapter 10
Bandwidth Limiter
The main problem of shared Internet connection is when one or more users download or
upload big volume of data and occupy great part of the line connected to the Internet (so
called bandwidth). The other users are ten limited by slower Internet connection or also may
be affected by failures of certain services (e.g. if the maximal response time is exceeded).
The gravest problems arise when the line is overloaded so much that certain network services
(such as mailserver, web server or VoIP) must be limited or blocked. This means that, by data
downloads or uploads, even a single user may endanger functionality of the entire network.
The Kerio Control’s Bandwidth Limiter module introduces a solution of the most common
problems associated with overloads of the Internet connection. This module is capable of
recognizing connections where big data volumes are transmitted and it reserves certain part
of the line’s capacity for these transmissions. The remaining capacity is reserved for the other
traffic (where big data volumes are not transmitted but where for example response time may
play a role).
10.1 How the bandwidth limiter works and how to use it
The Bandwidth Limiter module provides two basic functions:
Speed limits for big data volumes transmissions
Kerio Control monitors all connections established between the local network and the
Internet. If a connection is considered as a transmission of big data volume, it reduces
speed of such transmission to a defined value so that the other traffic is not affected. The
bandwidth limiter does not apply to local traffic.
Note: Bandwidth limiting does not depend on traffic rules.
Speed limits for users with their quota exceeded
Users who have exceeded their quota for transmitted amount of data are logically
considered as those who are often download or upload big data volumes. Kerio Control
enables to reduce speed of data transmission for these users so that other users
and network services are not affected by their network activities. This restriction is
automatically applied to users who exceed a quota (see chapter 16.1).
10.2 Bandwidth Limiter configuration
The Bandwidth Limiter parameters can be set under Configuration → Bandwidth Limiter.
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