3.8.1. Feature Description 
IPv6 is to replace IPv4 in the near future. This is expected to overcome
many limitations and problems that result from using IPv4. The use of
IPv6 for VoIP offers some crucial benefits, for instance:
- With IPv6, NAT (Network Address Translation) will no longer be needed except for network masquerading, as the total amount of available IP addresses will be sufficient. When NAT is used, the delivery of audio packages in VoIP connections requires workarounds, which means that audio transmission problems may occur.
- IP packet routing is expected to be more efficient.
- IPv6 has built-in quality of service (QoS) capabilities, especially for realtime applications.
- Signaling (TLS) and payload encryption (SRTP) is also supported with IPv6 (see "Signaling and Payload Encryption (SPE)").