Broadband Bringing Home the Bits (2002) / Chapter Skim
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2 What Is Broadband?
2 What Is Broadband?
Pages 62-81
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From page 62... ...
per phone line) or even ISDN service (the basic service offers two 64-kbps channels; experienced service can be at 128 kbps or higher)
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From page 63... ...
The speed and two-way requirement attempted to capture the intent expressed in the Telecommunications Act of 1996 that the speeds of what the act terms "advanced telecommunications services" should exceed the rates offered by the technologies available to residential customers at the time of the act's passage.4 At the time of the act's passage, residential customers were generally limited to dialup service (then typically no more than 33.6 kbps)
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From page 64... ...
Numerous groups would stand to benefit from workable definitions of what constitutes broadband. They include: · Consumers, who would like to be able to evaluate service offerings to see if the offerings are likely to meet their needs; · Service providers, who would like to develop, invest in, and deploy services that consumers will need and want; · Application and content developers, who would like to understand and track the connectivity performance options available to consumers; · Policy makers or regulators, who seek to monitor broadband service deployment and measure the impact of policy or regulatory decisions on deployment, define the characteristics of services eligible for tax credits or loans, or define the characteristics of services required in build-out commitments associated with regulatory relief; and · Public interest groups, which seek to evaluate capabilities available to consumers and to understand the implications of alternative policy approaches that influence those capabilities.
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From page 65... ...
As indicated earlier, the effective speed for interacting with an Internet host is not merely a function of the performance of the broadband local access link it depends on the entire path between the host and the user, and also on the loading on the host computer. As a result, depending on the circumstances, improvements in the performance of one link does not necessarily improve overall performance it may only shift the bottle
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From page 66... ...
that is shared by all users of the network. In this regard, residential fiber broadband networks will come to resemble the networking situation on university or corporate campuses, where local bandwidth is plentiful, but connectivity beyond the local campus is a comparatively constrained shared resource.6 The link to core Internet service providers is typically going to be paid for on a leased basis, and its costs rise as the bandwidth of the link increases.
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From page 67... ...
The asymmetric services typically found in today's residential broadband services were designed with one of two asymmetrical application classes in mind. One class is Web browsing, where a low-bandwidth upstream connection serves to carry a user's requests for Web pages, and the higher downstream connection returns the content the user has requested; e-commerce or other applications in which users interact via entering information in Web forms involve a similarly asymmetric communications model.
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From page 68... ...
While Web browsing has been a dominant application of residential broadband, accompanied by more limited audio/video streaming, peerto-peer applications have surged recently. These applications, which use many individual computers instead of a central server to distribute content, require significant upstream capacity for each computer.
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From page 69... ...
One principal implication of always-on broadband service is that, for the first time, residential users have nearly instant access to Web or other Internet services on demand. Before the advent of broadband services, residential and many small business Internet users were confined to using a dial-up line to access the Internet.
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From page 70... ...
Indeed, one sees this value reflected in value-stratification practices of several DSL service providers. They provide two tiers of residential service a cheaper one that requires users to go through a log-in screen when they wish to connect and a more expensive one that provides continuous connectivity.
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From page 71... ...
Thus, broadband Internet access and use of home networks will increasingly be interreated.l1 Spurred in large part by the initial deployments of broadband services to the home, a variety of home networking technologies are available in the consumer market (Box 2.1~. The year 2000 represented something of a turning point for the mass-marketing of these devices, seen in the increasing number of vendors offering products and in falling prices.
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From page 74... ...
Vendors also are integrating these functions into the modems themselves, aided by the minimal cost of adding home networking functionality to the silicon that implements the modem. Such integration extends to computers and Internet appliances as well, with these devices incorporating one or more home networking technologies.
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From page 75... ...
For example, exposing computers to the Internet on a continuous basis makes them more attractive and potentially vulnerable targets for attacks aimed at destroying data stored on them or otherwise disrupting their operation, viewing information stored on them, or manipulating them for use in launching attacks on other Internet services. ISPs may take some steps to help protect users, such as filtering out possibly hostile traffic (e.g., blocking transmission of NetBIOS packets, which could be used to alter or delete files and are generally only intended for use within local area networks)
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From page 76... ...
In the extreme case, access to noncached content might be poor enough to make it seem effectively filtered; consumer advocates express this concern about the fate of content from nonprofit sources, but the concern remains hypothetical. Service providers provision bandwidth, especially upstream, based on a particular business model which makes assumptions about who is sending how much of what to whom or on the assumption that a certain fraction of traffic can be cached.
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From page 77... ...
Implications of Network Design/Architecture Another parameter that deserves consideration is whether "broadband" refers exclusively to Internet service or is a more inclusive term that refers to a set of data communications services. Is the point of broadband to bring the Internet to the home or small business at much higher speed and with characteristics such as always-on, or is broadband really about delivering to the home a bundle of digital services, which include IP service, that are demultiplexed at a gateway?
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From page 78... ...
The speed-of-light transit time poses a fundamental limit to the rate at which data can be sent across the network using the data transmission protocols on which the Web is based. For today's typical Web page, a user "cruising the Web" will not see any material performance improvement once his or her access link has a capacity of about none local storage strategy, caching, keeps local copies of frequently used items.
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From page 79... ...
With a major source of congestion residing in the transit circuits that connect broadband providers to the Internet, improving local access performance above that bound will not improve the net performance seen by the user accessing the Internet. Everywhere in the Internet (except possibly on the access link)
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From page 80... ...
because they are unable to internalize the benefits realized by other service providers. One example of how this view comes into play is the asymmetry of broadband services.
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From page 81... ...
Today's residential broadband capabilities, which are typified by several hundred kilobits per second to several megabits per second downstream and several hundreds of kilobits per second upstream, support such applications as Web browsing, e-mail, messaging, games, and audio download and streaming. These are possible with dial-up, but their performance and convenience are significantly improved with broadband.
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