Realizing the Information Future The Internet and Beyond (1994) / Chapter Skim
Currently Skimming:
2 The Open Data Network: Achieving the Vision of an Integrated National Information Infrastructure
2 The Open Data Network: Achieving the Vision of an Integrated National Information Infrastructure
Pages 43-111
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From page 43... ...
The role government should take here is critical. The committee's advocacy of an Open Data Network is based in part on its experience with the enormously successful Internet experiment, whose basic structure enables many of the capabilities needed in a truly national information infrastructure.
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From page 44... ...
THE OPEN DATA NETWORK Criteria for an Open Data Network The Open Data Network envisioned by the committee meets a number of criteria: · Open to users: It does not force users into closed groups or deny access to any sectors of society, but permits universal connectivity, as does the telephone system. · Open to service providers: It provides an open and accessible environment for competing commercial or intellectual interests.
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From page 45... ...
This version of closed networking sacrifices a broad range of capabilities in exchange for a more reliable, secure, and available environment. · Flexibility in providing network services.
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From page 46... ...
Benefits of an Open Data Network Comparing the success of the open Internet to the limited impact of various closed, proprietary network architectures that have emerged in the past 20 years systems that eventually either disappeared or had to be adjusted to allow open access suggests that the wisdom of seeking open networks is irrefutable.3 Many of the proprietary networks that have played to captive audiences of vendor-specific networks for years are now rapidly losing ground as users demand and achieve the ability to interoperate in a world of heterogeneous equipment, services, and network operating systems. On the other hand, the Internet, and those networks that have "opened up," are enjoying phenomenal growth in membership.
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From page 47... ...
r OPEN DATA NETWORK ARCHITECTURE To realize the vision of an integrated NII, it is necessary to create an appropriate network architecture, that is, a set of specifications or a framework that will guide the detailed design of the infrastructure. Without such a framework, the pieces of the emerging communications infrastructure may not fit together to meet any larger vision, and may in fact not fit together at all.
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From page 48... ...
The Open Data Network must be seen not as a single, monolithic technology, but rather as a set of interconnected technologies, perhaps with very different characteristics, that nonetheless permit interchange of information and services across this set.
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From page 49... ...
These name spaces, since they are global, cannot be tied to a particular network technology choice but must be part of the technology-independent layers of the architecture. These somewhat more general service issues will benefit from a broad architectural perspective, which governmental involvement could sustain.
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From page 50... ...
Since the committee sees a continuous evolution in network technology, in end-node function, and, most importantly, in user-visible services, the network standards at all the levels must be evolvable. This requires an overall architectural view that fosters incremental evolution and permits staged migration of users to new paradigms.
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From page 51... ...
The Centrality of the Bearer Service The nature of the bearer service plays a key role in defining the ODN architecture. Its existence as a separate layer—the abstract bit-level network service provides a critical separation between the actual network technology and the higher-level services that actually serve the user.
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From page 52... ...
. Current data network technologies vary widely in their basic performance, from modem links (at 19,200, 14,400, 9,600, or fewer bits per second)
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From page 53... ...
THE OPEN DATA NETWORK I Layer 4 ~ Electronic ~ ~ Server J Applications C S~C \ Layer 3 Middleware Services \: ~ (3 \ :04 - ~ i \ \ Transport Services and / Layer2 \ Representation Standards / / \(fax, video, audio, text, and so on) / Layer 1 53 <= / / ~ / Open Bearer Service Interface ODN Bearer Service FIGURE 2.1 A four-layer model for the Open Data Network.
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From page 54... ...
The analog of the bearer service in the Internet suite is the IP protocol itself; this protocol is deliberately defined in a manner that is as independent from any specific technology as could be accomplished. This technology independence is accomplished by including in the IP protocol only those features that are critical to defining the service as needed by the higher levels, and leaving all other details for definition by whatever lower-level technology is used to realize IP in a particular situation.~3 IP is thus a very minimal protocol, with essentially two service features:~4 · The source and destination end-node address carried in the packet, and · The behavior that the user may assume of the packet delivery service, namely, the "best-effort" delivery service discussed below in "Quality of Service." The IP protocol's decoupling from specific technologies is one of the keys to the success of the Internet, and this lesson should not be lost in designing the ODN.
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From page 55... ...
Middleware: A New Set of Network Services Above the bearer service and the transport level (layers 1 and 2 of the ODN architecture) , but below the application level (layer 4)
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From page 58... ...
To address these issues, the middleware layer should provide, as a basic service, the means to effect payment transfer. Were this capability in place, an information seller could deal with any purchaser on a casual basis, trusting in the infrastructure to protect the underlying financial transaction.
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From page 59... ...
The alternative might be that a particular hardware choice becomes coupled to a particular proprietary or immutable set of higher-level services. Again, the objective of the layered ODN architecture is to decouple the low-level technology options (in this case both network and end-node choices)
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From page 60... ...
Browsing through digital libraries is one example; another is accessing one's own health or credit records, a service that implies the need for a high level of security assurance. The standards that define the access should provide for at least simple forms of database query operations, which can be packaged by the end-node device in some user-friendly way.
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From page 63... ...
Video will make a range of demands for network services. Delivery of a movie, for example, represents a longterm requirement for bandwidth, while exploring a database of short video fragments represents a very "bursty" load on the network.
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From page 64... ...
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From page 65... ...
Addison-Wesley, Reading, Mass. QUALITY OF SERVICE: OPTIONS FOR THE ODN BEARER SERVICE Best-Effort and Reserved Bandwidth Selvice An objective of the Internet has been to enable two computers to agree privately to implement some new service, and then implement it by exchanging packets across the network.
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From page 66... ...
The best-effort service and the current cost structure of the Internet are related. The original motivation for packet switching, made available almost 30 years ago, was to permit statistical sharing among users, who were willing to accept the variable delays of best-effort service in exchange for much lower costs.
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From page 67... ...
To define the minimum services that must be provided everywhere in the NII, it is necessary to establish a baseline of defined mandatory functionality. Without some such criteria, any provider could essentially market any network technology or service as being a part of the NII, and users would have no assurance that it would actually be useful.
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From page 68... ...
This reality requires that the basic service of the NII be characterized in an adaptable way that takes into account both power and universality. As a result, the committee's definition of NII compliance has two parts: · First, an evolving minimum set of basic services, both bearer services and application services, will be required without exception for NII-compliant systems.
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From page 69... ...
This approach has been very effective in practice and seems to represent a middle ground in defining compliance, pushing for interoperation and openness where possible but at the same time accepting the wide range of specific capabilities provided by existing network technology (Box 2.3)
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From page 70... ...
It thus concludes that the bearer services necessary to provide these services should be a long-term objective of the NII. STANDARDS Role of Network Standards To make the vision of an integrated NII a reality and to define NII compliance, it is necessary to specify the technical details of the network.
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From page 71... ...
This situation is rather different from that in the traditional telephone network, where most of the function was implemented in the interior of the network, and the user equipment, the telephone itself, had characteristics dictated largely by the telephone company. With the advent of computer networks in the 1970s and the strong coupling to computer research, the clear demarcation between users' systems and the network began to blur, and uncontrolled equipment appeared more frequently at user sites, to be attached directly to data networks.
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From page 72... ...
Similarly, in the early days of the Internet, the standards were set by a body established and funded by the Department of Defense, which (for the DOD) had a mandate to provide data network standards.26 No such mandate exists in the larger network context of today.
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From page 73... ...
Setting Standards for the NIIPlanning for Change Is Difficult But Necessary Managing the process by which the NII network environment evolves is one of the most critical issues to be addressed. Planning for change
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From page 74... ...
Addressing and Naming The Open Data Network envisaged by the committee will surely grow to encompass an enormous number of users and will be capable of interconnecting every school, library, business, and individual in the United States, extending beyond that to international scale. The ability to communicate among such a huge set requires the ability to name the desired communicant.
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From page 75... ...
The Internet and the telephone naming systems' simultaneous arrival at a crisis suggests that perhaps a common solution can be developed.27 The current address spaces of the Internet and the telephone network are a low-level framework suited for naming network and telephone locations and delivering data and voice. This framework is not used for naming users of the network or service providers or information objects, all of which must be named as well.
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From page 76... ...
The government and the existing private-sector standards bodies should cooperate to ensure that the resulting decision meets the needs of the future NII. Sustaining a discussion among the players about core issues such as addressing, and then creating a context in which the resulting decisions are actually implemented, is an example of an effort in which government action could have significant payoff.
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From page 77... ...
The NII will require continuous support to keep it up and running and to ensure that users have a high level of available service. Since the NII is likely to be a conglomeration of many interconnected networks, the network management function must be able to interoperate in a highly heterogeneous environment that is in a continual state of change, growth, and improvement.
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From page 78... ...
SECURITY AND THE OPEN DATA NETWORK Securing the Network, the Host, and Information There are certainly advantages to having a ubiquitous open data highway. The telephone system, for example, is ubiquitous in the sense that attaching to the telephone network makes it possible to reach and be reached by any telephone.
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From page 79... ...
Many public provider networks provide such functionality. The openness of the telephone network is occasionally a detriment, as with prank calls, telephone harassment, and unwanted telemarketing.
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From page 80... ...
Today, users view the Internet as reasonably stable, but it is known that it can be seriously disrupted by abuse from an end node, either by gross flooding of the network with traffic or by the injecting of false control packets that disrupt the internal state of the network, for example, the routing tables. There is evidence in the network communities of increasing concern about security, concern heightened by reports of incidents and abuses.32 For the last several years, all proposals for Internet standards have been required to include discussion of impacts on security.
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From page 81... ...
Another model, so-called discretionary control, typically involves user authentication and access control lists to identify the users permitted to access information objects. This sort of control is widely used in systems
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From page 82... ...
This separation means that the encryption key can be widely publicized (e.g., listed in name servers) , while the decryption key is kept secret.
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From page 83... ...
The need to identify and authenticate users exists at many levels of the security architecture. At the network level, it is necessary to identify users for purposes of accounting and billing.
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From page 84... ...
FINDING AND BALANCING OPPORTUNITIES TO BUILD TOWARD CONVERGENCE As the committee has pointed out in Chapter 1 and above, a diverse but interrelated set of expectations and requirements is driving current efforts aimed at developing a U.S. national information infrastructure.
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From page 85... ...
The main goals of the current HDTV design were limited to the primary issues of concern- to support television with higher resolution and to efficiently use broadcast television channels with high-resolution signals. It is ~mportant to expand these goals in light of the emerging NII and its applications.
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From page 86... ...
A key ingredient in this lack of consensus is that there is no widely agreed upon method as to how, or if, cable infrastructure will attach to the desktop computer in the home, to the data networks that exist (or are being planned) , to business environments, and so on.
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From page 87... ...
For example, the telephone network provides symmetric bandwidth to and from the user, while the cable networks provide vast bandwidth to the user, but little or no return communication. Such asymmetry is a potential limitation to the development of an open NII, because it means that becoming a producer of information (whose communication into the network requires large bandwidth)
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From page 88... ...
The two separate services cannot see each other, but the second could grow to be NII compliant in its own right. · Option 3 The idea of separate services for video delivery and open bearer service becomes more interesting for future systems with digital video encoding.
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From page 89... ...
Such a service would permit the objectives of the ODN to be supported at the same time as other services dedicated to the entertainment sector. Need for Government Action in Balancing Objectives Because there will be real incremental costs in engineering access circuits to the home to meet broad NII objectives of the kind expressed in the Open Data Network,4i the committee concludes that this is a time when the government, by direct action, can materially influence the course of the NII.
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From page 90... ...
ACTING NOW TO REALIZE A UNIFIED NII There is a definite role to be played by government in the pursuit of an open and flexible national information infrastructure, especially as commercial providers begin to figure ever more dominantly in the deployment of network technology. Left to their own devices, commercial providers will properly serve the markets that offer them growth and profitability.
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From page 91... ...
RECOMMENDATION: Technology Deployment The committee recommends that the government work with the relevant industries, in particular the cable and telephone companies, to find suitable economic incentives so that the access circuits (connections to homes, schools, and so on) that will be reconstructed over the coming decade are engineered in ways that support the Open Data Network architecture.
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From page 92... ...
A greater testbed effort by NSF would imply a departure from its normal pattern of funding, which involves the submission and evaluation of individual proposals from various sites and does not naturally lead to the required degree of direction setting, coordination, and architecture leadership. Research to Develop Network Architecture The Open Data Network architecture is a plan that defines the integrated NII's key aspects and how they fit together.
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From page 93... ...
The power of IP is that it can be made to work over almost any network technology. Once the technology independence is augmented with complex requirements for QOS, this power may be lost.
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From page 94... ...
Issues for the Lower Levels: Scale, Robustness, and Operations The ODN architecture must, of course, incorporate a number of specific technical developments, each of which must be explored as part of the overall NII development. Summarized below are a number of issues, also raised early in this chapter, that are certainly under study today but are not yet sufficiently understood to enable meeting needs of the future.
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From page 95... ...
Quality of Service The NII will support a diversity of applications ranging from current Internet services such as e-mail, file transfer, and remote login to such new applications as interactive multimedia video conferencing, transmission of medical images, and real-time remote sensing. Each of these applications has different requirements for such QOS measures as delay, throughput, and reliability.
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From page 96... ...
Research to generalize these ideas and propose a new generation of transport protocol would be very valuable. Network Control Functions Network controls are needed so that a very large and decentralized NII will be able to react to traffic overloads, network dynamics, and hardware and software failures.
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From page 97... ...
has yet to be done, the outcome of which is necessary to set the proper guidelines for key aspects of the lower levels. All of these control issues are the subject of current research, many are being tested in the various networking testbeds, and work on these issues will support multiple needs such as those discussed under "Quality of Service" above.
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From page 98... ...
Picking among the design options is a matter of both available technology and policy. Specifically, the government could sponsor research to explore the options for several key features: · Access circuit technology that could provide very efficient delivery of identified traffic classes such as video and at the same time support the general sorts of services, including multimedia mixed data traffic, envisioned for the NII; · Access circuits that provide cost-effective mixing of "bursty" traffic from several sources, as well as a means to deal with transient congestion by reflecting it back to the end nodes; and · Access circuit technology that could provide for a cost-effective variation in services for bidirectional traffic, to accommodate a range of end-node needs for capacity into and out of the network.
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From page 99... ...
As the committee has observed, what distinguishes an information infrastructure from a basic data network is a defined and implemented set of higher-level services, the middleware layer, which provides an environment more directly suited to the advanced applications that will run there. The middleware layer is a much less mature component of networking than the lower layers, which have been explored and reduced to practice in a number of cases.
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From page 100... ...
Some of this work was contemplated in recently proposed legislation; relevant work would also fall under the Information Infrastructure Technology and Applications (IITA) component of the HPCC initiative.
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From page 101... ...
Additional research and development should be done on technical mechanisms, better approaches to operation, and new approaches to training and education. Methods and technology for ensuring security are relevant to both the lower levels of the network and to the higher levels of the information infrastructure.
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From page 102... ...
Research in the Development of Software The continuing need for research in means to develop large and complex software packages is not new, nor is it specific to networking and the information infrastructure. At the same time, it is a key issue for which there seems no ready solution.
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From page 103... ...
Experimental Research in Middleware and Application Services Conducting testbed experimentation at the middleware level is usually less problematic than doing network research, because operation of experimental higher-level services cannot easily disrupt the ongoing operational use of the network by applications not depending on those ser
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From page 104... ...
104 REALIZING THE INFORMATION FUTURE vices. The Internet thus remains a major facility for development and evaluation of middleware services, an opportunity that should be recognized and encouraged.
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From page 105... ...
RECOMMENDATION: Network Research The committee recommends that the National Science Foundation, along with the Advanced Research Projects Agency, other Department of Defense research agencies, the Department of Energy, and the National Aeronautics and Space Administration, continue and, in fact, expand a program of research in networks, with attention to emerging issues at the higher levels of an Open Data Network architecture (e.g., applications and information managements, in addition to research at the lower levels of the architecture. The technical issues associated with developing and deploying an NII are far from resolved.
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From page 106... ...
Some of the uses describe rather different situations from that which is described in this chapter. For example, the telephone companies have been developing a concept they call open network architecture.
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From page 107... ...
11. The committee recognizes that the Information Infrastructure Task Force has begun to explore the concept of technically based "road maps" for the NII.
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From page 108... ...
The way this decision is settled will have real business consequences for the telephone companies and other ATM network providers.
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From page 109... ...
30. The committee recognizes that security is an emphasis of the administration's Information Infrastructure Task Force, but it seeks a sufficiently broad and deep technical framework, beginning with a security architecture.
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From page 110... ...
Recognition of this problem is developing in the relevant industries, but problems of design and implementation remain. See "National Information Infrastructure and Grand Alliance HDTV System Operability," February 22, 1994.
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From page 111... ...
44. The NSF-ARPA-NASA digital libraries initiative solicits proposals for research in three areas: (1)
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