21
Note that in some cases NAT traversal is not necessary. Some public service providers
of IP telephony keep track of the actual IP address used to register a phone, and the
one used in the SIP requests from the same phone, and then replaces the addresses in
the SIP messages.
STUN
STUN (Simple Traversal of UDP through NATs) is a protocol that
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routing. STUN is commonly used in real-time voice, video, mes-
saging, and other interactive IP communication applications.
The protocol allows applications operating through a NAT to
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mapped (public) IP address (NAT address) and port number
that the NAT has allocated for the application’s User Datagram
Protocol (UDP) connections to remote hosts. The protocol
requires assistance from a 3rd-party network server (STUN
server).
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SIP server supports STUN. A suitable STUN server is usually
provided by the VoIP service provider.
Note: STUN might also be referred to as Session Traversal
Utilities for NAT.
STUN host
The IP address or public name of the STUN server.
Offer ICE
ICE (Interactive Connectivity Establishment), is a STUN addi-
tion that provides various techniques to allow SIP-based VoIP
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for both endpoints to identify the most optimal path for the media
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STUN protocol that enables NAT traversal when both endpoints
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in terms of bandwidth that must be provided by the provider, and
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last resort when endpoints cannot communicate directly.
TURN User
User authentication name on the TURN server.
TURN host
The IP address or public name of the TURN server.
Password
User authentication password on the TURN server.
On phone:
(
MENU
)
>
SETTINGS
>
ADVANCED
> (PIN) >
NAT TRAVERSAL
(6,2,3).
SETTINGS
