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The New Public Network

Given the revolutionary changes in telecommunications, it is clear that we are moving toward a new public network. The new public network needs to have end-to-end digitalization. We began implementing digital technology in the early 1960s, and we've done quite well at getting it deployed throughout the various backbone networks. Worldwide, probably some 80% of backbones are now digitalized. However, the local loop—that is, the last mile between the subscriber and the network—is still largely analog. Only around 7% of the subscriber lines today are digital, so the vast majority of users are functionally limited to analog usage.

We face an incredible modernization task to digitalize the local loop and to truly make the network digital from end-to-end. However, the even greater challenge rests in the "last mile" economics and politics. The regulatory and political issues are critical indeed. Without broadband access, the Internet can't grow, advanced applications can't take off, revenues can't be realized, and we can't progress. The local loop is largely in the control of the incumbent telephone companies worldwide, and they do not seem to have the political and economic incentive to make end-to-end digitalization happen. There's lots of discussion on how to resolve this—by regulation, by enforcement, by market forces. When we find some resolution, the telecommunications industry will blossom like never before. (See Chapter 2, "Telecommunications Technology Fundamentals," and Chapter 13, "Broadband Access Solutions.")

Another factor that affects the new public network is that we are now in the last years of the electronic era and in the first years of a new generation of optical, or photonic, networking. Conversions between electrical and optical signals reduce the data rates and introduce the potential for distortion; hence, they affect the data stream. To eliminate these conversions, we need to work toward achieving an end-to-end optical networking scenario. (See Chapter 12.)

The new public network must also be an intelligent programmable network. That is, we want to distribute service logic via databases on a networkwide basis so that anywhere in the world, you can access any service or feature you want, regardless of the network provider or network platform that you are connected to. This intelligent programmable network requires some form of communication between the network elements. In the public switched telephone network (PSTN), this communication is done through the use of high-speed common-channel signaling systems that allow real-time communications between the network elements. In essence, it's like a private subnetwork. No voice, data, or image traffic is carried on these channels—only the signaling information that dictates who's calling, what rights they have, what features and services they want to use, and so on. Because there are many manufacturers and providers of network platforms, it's important that the programmable platforms use open application programming interfaces. (See Chapter 5, "The PSTN," and Chapter 10, "Next-Generation Networks.")

The new public network requires a new broadband infrastructure that has very high capacities and offers multichannel service (that is, one physical medium can carry multiple conversations). The two dominant media types in the broadband arena are high-speed fiber (run as close as possible to the customer) and broadband wireless (over the last few feet or meters to the customer, if needed). (See Chapter 13.)

It is very important that the new public network be a low-latency network. Humans cannot suffer much delay—on the order of 650 milliseconds—in receiving information before it becomes unintelligible. To give you some perspective on this, on a satellite call, the delay between the time you say hi to the time you hear the response is annoying, but it lasts only 500 milliseconds. Current infrastructures, such as the Internet, may impart as much as 1,000 or 2,000 milliseconds of delay. They therefore play havoc with any type of traffic that is delay sensitive—and voice, video, and multimedia are all very delay sensitive. So when we say we want to build low-latency networks for the future, we mean networks that impose no delays that result from congestion points. (See Chapter 10.)

Another characteristic of the new public network is that, in contrast to today's world, where we have separate platforms for each of the traffic types, the platforms need to be multiservice—they have to accommodate voice, data, and video streams, as well as any streams invented in the future. (See Chapter 10.)

The new public network should also be agnostic. That is, it should not follow only one protocol, but it should understand that the universe truly is multiprotocol and we will always have multiple protocols to deal with. The best way to create an agnostic network is to have a box that enables interfaces for the most prevalent of the data protocols. (See Chapter 9, "The Internet: Infrastructure and Service Providers.")

The new public network also needs to include a new generation of telephony services, one that makes use of packet-switching technologies to derive transmission efficiencies, while also allowing voice to be bundled in with more standard data applications, to provide for more robust environments. (See Chapter 11.)

Quality of Service (QoS) guarantees are an absolute prerequisite for the new public network. The network must be able to distinguish between the various traffic types so that it can apply the appropriate network resources and ensure that the latency requirements are being met, that the loss requirements are being met, and that the bandwidth required is being allocated. (See Chapter 10.)

Finally, encryption and security services are necessary in telecommunications devices and networks. Once upon a time, this was a separate function within the company, but now it is an essential element of telecom service. (See Chapter 11.)

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