Doctor of Philosophy, Computer Science

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Figure 1. --- Host Centered H/C Network Architecture

Initial Network Architectures connected Peripherals not Computers. As such all the "Intelligence" resided at the H/C Computer (Node). This early Network Architecture (NA) was based primarily on John von Neumann's General Purpose Programmable Computer conceived in 1945. The only improvement provided by the H/C Network Architecture was the creation of remote Input and Output Devices.

However, the only benefit afforded by this early NA was to keep Users out of the Computer Room. The Major Benefit of sharing Information and thus making People more productive within the Enterprise still alluded the Information Technology (I/T) Industry. Dumb Input and Output Devices distributed throughout the Enterprise did not provide the "Sharing of Information" Benefit. A NA that would provide for the connectivity of multiple Processors to distribute the Processing Load and thus share information as Commodore Harper suggested in 1977 at a local Association of Systems Managers (ASM) meeting was required.

Figure 2. --- LANs allow People to "Share Information"

Not much progress was made until the mid-1980s. Personal Computers (PCs) had permeated the Small Business and Department Environs of Large Enterprises. Small Business Owners and Department Heads realized that "Sharing of Information" would make their People more productive. Use of the PCs on the traditional "Stand-Alone" basis did not provide the 'Sharing of Information" Benefit. Connection of the individual PCs that were proliferating throughout the Enterprise --- Would also connect the People. Oddly enough it was the PC on every Desktop (i.e. A Bill Gates Proclamation) that precipitated the Local Area Network (LAN). We had to learn how to connect PCs in the Small Business or Departments within the Enterprise before we could connect the entire Enterprise. LAN Technology became the precursor "Building Block" for the NAs and Network Technologies we have Today.

Another words, we had to learn how to make People more productive at the Department Level before we could make them more productive at the Enterprise Level.

Figure 3. --- Network Acronyms

Thus the LAN Architecture became the first major "Breakthrough" in NA. The NA as we know Today originated at the Local Level but has scaled to the Enterprise Level. As the NA evolved to permeate and connect the Enterprise, a number of Network Acronyms were created to describe the extension of this basic NA. Wide Area Networks (WANs), Campus Area Networks (CANs), and Metropolitan Area Networks (MANs) all embody LAN Technology and allow us to "Share Information" making People more productive irregardless of their Physical Location --- "Enterprises without Walls".

As such the ultimate NA is constructed from Basic LAN NA Building Blocks that are interconnected to provide a transparent and ubiquitous "Information Transport Utility" to the People System Resource regardless of their Physical Location or Organization Affiliation (i.e. Virtual NA).

Figure 4. --- Internets/Intranets/Extranets

The next "Breakthrough" in the NA was the Access or Connectivity portion that allowed the Basic LAN NA to scale to the Enterprise and between Enterprises. The Internet along with Browser Technology provided "Universal Access" or the "Universal Client" to the World Wide Web (WWW) or Worldwide Public Highway. Thus People regardless of Physical Location and/or Organizational Affiliation could "Share Information" and become more productive.

The final "Breakthrough" in NA will be the complete extension, enhancement, and integration of Legacy H/C Applications to the new Internet NA Model. This evolution is already underway as H/C Applications are migrating toward multi-tiered web-based Client Server (C/S) Architectures providing "Universal Access" to Customers, Suppliers, Business Partners, and other Interested Parties. Thus "Sharing of Information" across Enterprise Boundaries supported by a viable NA truly enhances People's Productivity.

Figure 5. --- TCP/IP and OSI Models Converge

The OSI Model developed by the International Standards Organization (ISO) in 1977, set the Standard for LAN Services. Today, Networking Devices must comply with the OSI Model. The OSI Model ensures that Network Software and Hardware from various Vendors will work together. This is critical to ensure the NA constructed from the Basic LAN NA Building Blocks operates as a single seamless Entity.

The OSI Model is a Layer or Stack Model. Each layer starting at the bottom must be complied with before the next Layer is addressed. As such it is often referred to as a "Bottom-Up" Model.

• Physical Layer (Layer 1) --- Specifies how all hardware on the Network must be connected. Includes Network Interface Cards (NICs), Computer Ports, Cabling, and Connectors.
• Data Link Layer (Layer 2) --- Specifies the protocol for how the data (Signaling Stream) travels through the Network. Ethernet and Token Ring are examples of Signaling Streams.
• Network Layer (Layer 3) --- Specifies how different Signaling Streams can be integrated. Routing and forwarding of Data (Message Packet) is addressed by Layer 3.
• Transport Layer (Layer 4) --- Specifies how the Message Packets of various Signaling Schemes are directed to the different Nodes (Computers) of the Network. Layer 4 is critical because it provides the "glue" to tie the Components of the NA together. Transmission Control Protocol (TCP) resides at Layer 4.
• Session Layer (Layer 5) --- Specifies how the User interacts with the Network. This is where the User logs a User Id and Password to establish a Session with the Network. The Network Operating System (NOS) controls the Session and therefore must comply with Layer 5 to provide a seamless Network Connection.
• Presentation Layer (Layer 6) --- Specifies how the Signaling Scheme(s) sent over the Network is presented to the Receiving Node (Computer) in a form the Node can understand. Layer 6 translates the Signaling Scheme(s) to a Scheme the Receiving Node can present to the User. File Transfer Protocol (FTP), Hyper Text Transfer Protocol (HTTP), and Simple Network Management Protocol (SNMP) reside at Layer 7.
• Application Layer (Layer 7) --- Specifies the Network Services available to or provided by the Network Node (Computer). Print, File Sharing, E-mail, and other Network Services are included in Layer 7.

The Internet uses a system of Telecommunications Protocols that have become so widely used that they have become a de-facto standard. The Transmission Control Protocol/Internet Protocol (TCP/IP) originated in the late 1950's with the introduction of the Internet. TCP/IP is also a Layer or Stack Model (i.e. Protocol Stack) similar to OSI. As the Basic LAN NA Model evolved and became standardized through OSI the connection of the LAN NA to the Internet WAN NA was achieved by mapping OSI to TCP/IP. In fact, the Transport Layer of each Protocol Stack uses TCP.

As such, TCP/IP and OSI have created the "Standards Process" to control the growth, evolution, and scalability of the LAN and WAN Components of the NA.

Figure 6. --- Network Components

Five major Network Components comprise the Physical NA. These Components provide tradeoffs between cost, performance, and flexibility in both the LAN and WAN Environments.

Figure 7. --- Cable Alternatives

Media options are not only limited to Cable, but include Wireless Options as well. Wireless provides improved flexibility and adaptability. Wireless Use is expected to increase as performance and cost improves.

Figure 8. --- Transport Speeds

The "Sharing of Information" Objective to improve People Productivity requires that Information can be transported effectively between Nodes of the Network. After all, the Network is an "Information Transport Utility". Transport Performance depends on the Media and Network Technology employed.

Figure 9. --- Network Characteristics

The limiting factor regarding Network Performance has been Bandwidth. Bandwidth measures the "Information-Carrying Capacity" of the communication channels between the Nodes of the Network. As Network Usage increases, more Information is shared, and video begins to dominate the Information shared, Bandwidth becomes depleted. As such improvements in the Signaling Rate are required to maintain Network Performance. Network Types have evolved since the advent of Ethernet to provide improvements in Bandwidth. Ethernet has evolved from 10Mbps to 1000Mbps or 1Gbps Gigabit Ethernet. This is a 100 fold increase in Bandwidth in just 15 years.

Another way to increase Bandwidth is to modify the Signaling Scheme to carry voice, data, and video over the same "Pipe". Asynchronous Transfer Mode (ATM) can simultaneously transfer voice, data, and video over a single fiber optic cable achieving a Signaling Rate of 2Gbps+. Broadband capability allows multiple channels to carry multiple signals over a single medium (i.e. Fiber Optic Cable).

Although it is expected that Bandwidth will continually increase exponentially, increased usage along with our insatiable appetite for Video will continue to tax the Network resource of the Information System (I/S).

Figure 10. --- Network Topologies

Three principal Network Topologies describe how Nodes in a Network are physically connected. Ring and Star were very popular in the early 1960s, but have given way to the Bus Topology popularized by the PC and Client/Server (C/S) N-tier Architecture.

Figure 10. --- Internet/LAN NA Model for the Global Enterprise

Although the Internet was developed by the Department of Defense (DOD) Advanced Research Projects Agency (ARPA) in the late 1950's to support the U.S. Government's efforts to combat the "Cold War", it was not made available to the Private Sector until the early 1990s. However, during the forty intervening years a Network Infrastructure was built, enhanced, and extended which provided the "Backbone" for the onslaught of usage precipitated by the proliferation of the PC coupled with the development of the Basic LAN NA.

The Internet Network Infrastructure provided the foundation for interconnecting the component LAN NAs of everything from Individuals to Large Global Enterprises. In retrospect the forty year head-start fostered by ARPA provided a Network Infrastructure that could support the onslaught of "Content" (i.e. WWW) that started in the early 1990s. The Internet Network Infrastructure has no single point of failure; is not owned by any single Individual or Entity; can grow exponentially; and provides "Universal Access" which is Physical Location and Organization Affiliation Independent. The Internet is really a public "Network of Networks". It has become the prime Global "Information Transport Utility" used throughout the Planet.

Moreover, Internet Technologies have been ported to the Enterprise to improve connectivity within and between Enterprises of all types. Intranets and Extranets utilizing Internet Technologies along with advances in LAN Technologies have determined new ways of "Doing Business" never imagined by ARPA in the late 1950s. Legacy Applications based on the H/C Architecture of Von Neumann are being re-engineered to incorporate these Internet Technologies and thus breath new life into Applications that just a few years ago were considered unacceptable to function appropriately in the new e-Commerce Business World.

These re-engineered Applications have been re-structured to comply with innovations in Client/Server (C/S) and Internet/LAN NA. Legacy Applications originally architected for the H/C Model are now being re-architected for the C/S Architecture and Internet/LAN NA Models utilizing Internet Technologies. This provides an ubiquitous "Sharing of Information" Benefit to make People more productive irregardless of their Physical Location or Organizational Affiliation. The People Component has always been the limiting factor for the growth of IT. As such advancements in NA have had a significant impact on improved application of IT to the Enterprise. Further Developments in Internet/LAN NA will continue to improve People Productivity by providing enhanced access and connectivity that will allow the "Sharing of Information" Benefit to proliferate throughout the Planet.

Figure 11. --- e-Commerce Application supported by Internet/LAN NA

The Internet LAN NA Model has transformed the Architectures for the traditional Enterprise Legacy Applications. These new Applications are critical to allow Enterprise's of varying sizes and businesses to compete in the e-Commerce World. Transformation of traditional Business Processes to Business-to-Consumer (B to C), Business-to-Business (B to B), and Internal Business Processes (IBP) e-Commerce requires an Internet/LAN NA that allows "Sharing of Information" among diverse groups of People. As such this new way of "Doing Business" would not be possible without a NA that is scalable, provides "Universal Access", and is transparent to Physical Location and Organization Affiliation.

Figure 12. --- Benefits of B to C e-Commerce

To remain competitive, Enterprise's must continually provide B to C links to improve Customer Value. I just recently ordered some workout food from Netrition.COM. Netrition.COM is the Internet's Premier Nutrition Superstore. I could not have done this just a year ago. The reason I no longer purchase workout food from traditional sources (i.e. Gym were I workout) is that buying over the Internet/LAN NA model used by Netrition.COM provides improved Customer Value. Cost, Speed, Accessibility, and Availability are all factors that increase my Customer Value. Moreover, this also lowers the cost of "Doing Business" for Netrition.COM. As such e-Commerce Business, which would have been impossible without the Internet/LAN NA, benefits both sides of the B to C equation.

Figure 13. --- Benefits of B to B and IBP e-Commerce

Likewise the Internet/LAN NA Model provides Major Benefits to Enterprises. B to B that in the past was supported by numerous esoteric Enterprise Application Integration (EAI) techniques can now be standardized using the more common Internet/LAN NA Model. The most difficult issue with deploying an Enterprise Resource Planning System (ERP), was dealing with the numerous custom external Interface Systems involving many proprietary NAs.

The same Benefits attributable to B to B are attributable to IBP within the Enterprise. The Legacy Applications based on the H/C Architecture Model are being slowly transformed to the new N-Tier C/S and Internet/LAN NA Models. This provides competitive advantage to those Enterprise's who have re-architected their B to C, B to B, and IBP Applications. Enterprises that adopt the Internet/LAN NA Model to support their Business Plans will prosper. Those that fail do so will fail.

The future for NAs looks bright. The Internet/LAN NA Model made a major contribution to the proliferation of e-Commerce with the new "Dot Coms" as well as the re-engineering of Business Processes of older established "Brick and Mortar" Enterprises. Without the Internet/LAN NA Model the rapid growth of the Economy would not have been possible.

The NA is a Component Architecture. The Bandwidth and Accessibility (i.e. Universal Client --- Browser) Components will continue to improve providing increased performance at reduced cost.

Standardization of the Components will improve to allow improved application, deployment, and support of e-Commerce Application Solutions fostered by this Internet/LAN NA Model. The pioneering, customization, and experimentation provided by the early "Dot.COMs" such as Amazon.COM will be reduced. We will get better at building e-Commerce solutions based on a Component Internet/LAN NA Model. This will be of major import for migrating traditional H/C Legacy Applications to the new Internet/LAN NA Model.

While the future looks bright and People (i.e. The Limiting I/S Component) have reached a high level of empowerment, concerns over Security and Business Ethics cannot be ignored.

The downside of the improved "Sharing of Information" Benefit is the "Security of Information" Risk. As such extra effort must be employed to "Deploy Security" within these new and re-engineered e-Commerce Applications. Standards for "Security Components" must be developed, deployed, and verified. For example while ordering my workout food from Netrition.Com, I used a "Secure Link" for entering my Credit Card Information. While I knew the information I was entering (i.e. Information Sharing), I did not know what a "Secure Link" is or what Security Standard it represents.

The Internet is not owned or regulated by any single Individual or Entity. As such, anyone is free to flood this Public "Network of Networks" with their own Content. This is "Sharing of Information" I might not want to share. Thus the Internet/LAN NA Model with all its Benefits has also "opened the door" for Abuses. Components must be added to the NA to combat these Unethical Abusers to the same extent provided to improve the lot of the Benefactors.

2.) Encyclopedia of Computer Science, Anthony Ralston, Petrocelli/Charter, 1976

3.) Novell's Introduction to Networking, 2^nd Edition, Cheryl C. Currid and Mark Eggleston, Novell Press, 2000

4.) Simplifying LAN-WAN Integration, Corporate Guide to Routers & Bridges, Wellfleet Communications, Inc., 1993

5.) Integrating SNA & Multiprotocol LAN Networks, Wellfleet Communications, Inc., 1993

6.) Small Business Solutions for Networking, Alan Neibauer, Microsoft Press, 2000

7.) Internetworking with TCP/IP, Third Edition, Douglas E. Comer and David L. Stevens, Prentice-Hall, Inc., 1995

8.) Computer Networks and Internets, Second Edition, Douglas E. Comer, Prentice-Hall, Inc., 1999

9.) Virtual LANs, Marina Smith, McGraw-Hill Series on Computer Communications, 1998