6 • Overview
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S N O M
4 S N A T F
I L T E R
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1.1 Applications
The filter can be used in the following scenarios:
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Corporations. Corporations which operate their infrastructure be-
hind NAT and/or firewalls can talk to the public Internet through the
filter.
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Operators. Operators offer the NAT traversal feature to their cus-
tomers. Using the scalability feature of the filter, the operation of
large networks becomes possible.
•
Record specific calls for legal purposes. In many countries, opera-
tors must provide the possibility to record certain calls on request.
The filter can perform this task.
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Recording can be used for legal proofing (brokers, etc). The filter is
fully compliant with other SIP equipment and can, for example, put
between a PSTN gateway and SIP phones.
1.2 Features
The filter offers powerful features based on modern VoIP
technology:
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The built-in RFC3261-compliant SIP proxy makes additional exter-
nal SIP logic superfluous and simplifies the system setup.
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A built-in RFC3489-compatible STUN server for single IP addresses
allows clients to self-refresh their bindings
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Support for instant messaging, presence and all other SIP-compli-
ant applications.
•
Rich logging features allow easy maintenance.
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Recording functions based on number lists and expressions offer a
flexible way of filtering out information.
•
Recordings can be saved in WAV file format (the data rate is 6 MB
per hour).
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Almost stateless operation allows the filter to be used in server
farms. This offers a tremendous scalability and redundancy making
the product suitable for large operators.
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