Draytek Vigor2760 User Manual page 207

The major benefit of this mode is that you don't have to memorize your friend's IP
address, which might change very frequently if it's dynamic. Instead of that, you will
only have to using dial plan or directly dial your friend's account name if you are with
the same SIP Registrar.

Peer-to-Peer
Before calling, you have to know your friend's IP Address. The Vigor VoIP Routers will
build connection between each other.
Our Vigor V models firstly apply efficient codecs designed to make the best use of available
bandwidth, but Vigor V models also equip with automatic QoS assurance. QoS Assurance
assists to assign high priority to voice traffic via Internet. You will always have the required
inbound and outbound bandwidth that is prioritized exclusively for Voice traffic over Internet
but you just get your data a little slower and it is tolerable for data traffic.
Below shows the menu items for VoIP:
Vigor2760 Series User's Guide
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