Administrator’s Guide for SIP-T46G IP Phone1663. Enter the desired value in the SIP QoS (0~63) field.4. Click Confirm to accept the change.A dialog box pops up to prompt that the settings will take effect after reboot.5. Click OK to reboot the IP phone.Network Address Translation (NAT) is essentially a translation table that maps public IPaddress and port combinations to private IP address and port combinations. Thisreduces the need for a large amount of public IP addresses. The NAT feature ensuressecurity since each outgoing or incoming request must go through a translation process.But in the VoIP environment, NAT breaks end-to-end connectivity.NAT TraversalNAT traversal is a general term for techniques that establish and maintain IPconnections traversing NAT gateways. It is typically required for client-to-clientnetworking applications, especially for VoIP deployments. STUN is one of the NATtraversal 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-timevoice, video, messaging, and other interactive IP communications. The STUN protocolallows applications to operate behind a NAT to discover the presence of the networkaddress translator, and obtain the mapped (public) IP address and port number thatthe NAT has allocated for the UDP connections to remote parties. The protocol requires
