To provide high-quality voice and take advantage of the full voice feature set, which two...

Use multiple egress queues to provide priority queuing of RTP voice packet streams and the ability to classify or reclassify traffic and establish a network trust boundary.

Use 802, 1Q trunking and 802.1p for proper treatment of Layer 2 CoS packet marking on ports with phones connected.

Implement IP RTP header compression on the serial Interface to reduce the bandwidth required per voice call on point-to-point links.

Deploy RSVP to improve VoIP QoS only where it can have a positive impact on quality and functionality where there is limited bandwidth and frequent network congestion.

Map audio and video streams of video calls (AF41 and AF42) to a class-based queue with weighted random early detection.