Network Address Translation - Yealink SIP-T46G Administrator's Manual

Administrator's Guide for SIP-T46G IP Phone
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Network Address Translation (NAT) is essentially a translation table that maps public IP
address and port combinations to private IP address and port combinations. This
reduces the need for a large amount of public IP addresses. The NAT feature ensures
security since each outgoing or incoming request must go through a translation process.
But in the VoIP environment, NAT breaks end-to-end connectivity.
NAT Traversal
NAT traversal is a general term for techniques that establish and maintain IP
connections traversing NAT gateways. It is typically required for client-to-client
networking applications, especially for VoIP deployments. STUN is one of the NAT
traversal techniques supported by IP phones.
STUN (Simple Traversal of UDP over NATs)
STUN is a network protocol, which is used in NAT traversal for applications of real-time
voice, video, messaging, and other interactive IP communications. The STUN protocol
allows applications to operate behind a NAT to discover the presence of the network
address translator, and obtain the mapped (public) IP address and port number that
the NAT has allocated for the UDP connections to remote parties. The protocol requires
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VoIPon www.voipon.co.uk sales@voipon.co.uk Tel: +44 (0)1245 808195 Fax: +44 (0)1245 808299
Enter the desired value in the SIP QoS (0~63) field.
Click Confirm to accept the change.
A dialog box pops up to prompt that the settings will take effect after reboot.
Click OK to reboot the IP phone.