Topology Hiding - AudioCodes Mediant 8000 Installation, Operation & Maintenance Manual

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43.3

Topology Hiding

The SBC application implements Topology Hiding by limiting the amount of topology
information displayed to external parties. For example, IP addresses of ITSPs'
equipment (e.g. proxies, gateways, and application servers) can be hidden from
outside parties.
The topology hiding is provided by implementing back-to-back user agent (SBC) leg
routing:
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Strips all incoming SIP Via header fields and creates a new Via value for the
outgoing message.
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Each leg has its own Route/Record Route set
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Modifies SIP To, From, and Request-URI host names
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Generates a new SIP Call-ID header value (different between legs)
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Changes the SIP Contact header to the device's own address
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Layer-3 topology hiding, by modifying source IP address in the SIP IP header
43.4 SIP Normalization
The SBC application can overcome interoperability problems between SIP user
agents. This is achieved by the following:
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Manipulations of SIP URI user part and host part.
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Connection to ITSP SIP trunks on behalf of an IP-PBX – the board can register
and utilize a user name and password to authenticate for the IP-PBX.
Installation & Operation Manual
Late rouge detection - if a SIP session was gracefully terminated and
someone tries to "ride on it" with rouge traffic from the already terminated
RTP and SIP context, the VoIP Firewall will prevent this from occurring
Disconnects call (after user-defined time) if the RTP connection is broken
Black/White lists for both Layer-3 firewall and SIP classification.
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Mediant 8000
Document # LTRT-92224