s. Due to the lack of interoperability standards for Although VoFR implementations are efficient and voice communications over Frame Relay, IP, and ATM, cost effective for intra-enterprise or intra-corporate the vendors must develop proprietary interworking communication, there are considerations, such as solutions. quality, to be made regarding the use of packetized There are many situations in which interworking be- voice when dealing with non-Frame Relay WAN, or off- tween technologies is required within a corporate net- net, users. Figure 3.2-4 illustrates how a typical work. For example, corporations that are running data VoFR implementation might look, supporting simulta- and VoFR might require VoIP to extend the network to neously both on-net (VoFR) and off-net (POTS) remote locations that don't have a Frame Relay in- implementations. frastructure without deploying additional equipment. This may also be required for telecommuters working from home, salespeople working from hotel rooms, and Equipping your company's network resellers that want to access information. for VoFR You can deliver voice over any carrier's frame relay Voice over Frame Relay services, assuming that you have ensured that the carrier's frame relay network can guarantee a delay and In the last few years, data networks have been growing at jitter that adequately meets your company's needs. a much faster rate than voice networks, mainly due to the Most of the major carriers offer frame relay services, growth of the Internet. Soon the amount of data traffic including MCI WorldCom and AT&T Solutions. Few will exceed that of voice traffic. As a result of this trend, carriers offer managed VoFR services. However, AT&T more and more voice is being sent over data networks Solutions announced a managed VoFR service called (VoFM, VoIP, and VoATM) rather than data being sent Managed Multiservice Networking (MMN). Unless over voice networks (via V.34 and V.90 modems). you use a managed VoFR service, such as that offered When Frame Relay was introdu