This standard addresses IP-based digital telephony (sometimes referred to as Voice over IP) on the VHN. As the VHN is inherently digital it does not address analog telephony, nor does it address non-packet digital telephony, such as the streaming service provided by ISDN. However, future versions of this standard may address non-IP telephony. Also, note that this Standard defines the requirements for implementing a telephony function on a VHN.