IP telephones

IP/Ethernet telephones should support the following features:

• At least a G.711 encoder, though other types of encoders may be supported as well.
• Echo-cancellation with a 64 msec echo cancellation tail.
• If equipped with a single external Ethernet port, 802.1p priority and 802.1Q VLAN indication facilities.
• If equipped with multiple external network ports or extra internal ports, an Ethernet switch supporting 802.1p and 802.1Q for priority, queuing, and VLAN functionality.
• Any internal Ethernet switch should prioritize voice and signalling over data with voice and signalling at the same highest priority.
• Signalling traffic transferred over a TCP connection.
• DiffServ marking assigning the highest priority to voice signaling and bearer traffic in alignment with the DiffServ class assignments in the IP routers.
• Network-facilitated telephone power.