As Bob Dylan once sang, “The Times They Are a-Changin.” Change, however, comes with new challenges, and with something the size of the global telephone network, change takes time. Many think the Public Switched Telephone Network (PSTN) and Internet are separate things, yet the Internet was built upon PSTN infrastructure for its transmission. Decades ago, experts could see that data over voice networks would transition to voice over data networks once voice/data volumes inverted. That inversion occurred in 2000 and foretold Internet dominance as the fundamental network approach.
In 2000, the main telephony standards groups realized they needed to embrace Internet Protocol (IP) and Session Initiation Protocol (SIP) technologies and stopped working on Time Division Multiplexing (TDM) based technologies of the past, but they had a problem. 100 years of building telephone networks connecting billions of people world-wide with 5-9’s reliability was the bench-mark against which any new voice service would be measured. Now voice would be competing with an explosion of new data applications for transport resources in the network. Further exacerbating the issue, bandwidth-consuming video applications would be provided by not only the network provider (e.g. IPTV) but also by competing over-the-top (OTT) service providers.
The flood of packet volume can swamp that of voice packets traversing the network and destroy voice quality. On top of that, video packets which also greatly increase packet volume also need to adhere to strict requirements for latency, jitter, and packet-loss to which web traffic is insensitive. The providers are challenged with the need to continue to deliver high quality real time services while accommodating this wave of video-centric applications and doing so in a way that delivers good economics for their business. Some means is needed to enable these applications to play nicely with each other. The first challenge is to have visibility into the operation of the network, either through explicit signaling from the application layer or implicitly through traffic inspection. The second challenge is to have policy control mechanisms that can sort out the competing needs for network resources and then fairly optimize and execute controls in the network including capabilities as simple as enforcing QoS and as powerful as video error repair or video caching.
The third challenge is for all parties in the service supply chain to cooperate in the distribution of revenues commensurate to the value provided to the customer. Before, service and network were one vertical capability — one built a voice network for the voice service. Today things are not so simple, a horizontal network capability supports a multitude of vertically-oriented applications. No longer can cross-subsidization of the network by a single application (voice) be taken for granted. This calls for network intelligence, visibility and management to facilitate changes in business models so that the return on network investment can invest in the build-out of future broadband networks. All parties need to embrace change and find a way to share that enables growth in the communications market and cool new services as the PSTN wanes and IP comes of age.