What Does Advanced Research Projects Agency Network Mean?

The Advanced Research Projects Agency Network (ARPANET) is a predecessor to the modern Internet. It was conceptualized in the 1950s, when computer scientists needed something better than the then available but unreliable switching nodes and network links.

There were also only a limited number of large, powerful research computers, and researchers with access were separated geographically. The Advanced Research Projects Agency (ARPA) commissioned the development of an advanced and reliable way to connect these computers through a newly devised packet switching network, which was known as ARPANET.

Techopedia Explains Advanced Research Projects Agency Network

The ARPANET was a project funded by the U.S. government during the Cold War, in order to build a robust and reliable communications network. This was done by connecting various computers that could simultaneously communicate in a network that would not go down and continue running when a single node was taken out.

The initial groundwork for a computer network was laid by Joseph C. R. Licklider of Bolt Beranek and Newman (BBN). Licklider became the head of the behavioral sciences and command and control programs at ARPA in October 1963. He then convinced Ivan Sutherland and Bob Taylor to work on this concept. In his office, Bob Taylor had three computer terminals connected to the three ARPA-sponsored computers:

• The System Development Corporation (SDC) Q-32 at Santa Monica
• Project Genie at the University of California, Berkeley
• Multics at the Massachusetts Institute of Technology

When Taylor needed to talk to someone at another computer, he would transfer to a different terminal for each connection. This was frustrating and led to the concept of one terminal/computer connected to a number of other terminals. This idea paved the way for the ARPANET and, eventually, the modern Internet.

Paul Baran of Rand Corporation concluded that the strongest kind of network would be a packet switched network that would use any available communication line, regardless of the status of other lines. The ARPANET originally connected four computers, as follows:

• A Honeywell DDP 516 computer at University of California, Los Angeles
• An SDS-940 computer at the Stanford Research Institute
• An IBM 360/75 at University of California, Santa Barbara
• A DEC PDP-10 at the University of Utah

Compatibility issues surfaces as more computers were connected to the network. These problems were solved in 1982 through the development of Transfer Control Protocol/Internet Protocol (TCP/IP).

Architecture of ARPANET

The architecture of ARPANET was designed to be a decentralized and fault-tolerant communication system that could connect each computer on a network without needing dedicated phone connections between them. Data was transmitted over the network using packet switching, a method that breaks data into small packets and sends them individually over the network.

The network was built using a hierarchical structure, with backbone nodes at the top and smaller nodes at the bottom. The backbone nodes were responsible for carrying the majority of the network traffic and were typically located at major research institutions and government agencies. The smaller nodes were located at universities and other research institutions and connected to the backbone nodes.

To ensure that the network was fault-tolerant, ARPANET used a distributed routing algorithm that allowed each node to make its own decisions about the best path for data to take. Each node was equipped with a special-purpose computer called an Interface Message Processor (IMP) responsible for routing data between nodes. The IMPs communicated with each other using a protocol called Network Control Program (NCP), which was developed specifically for ARPANET.

In addition to packet switching and distributed routing, ARPANET introduced several other key concepts still in use today. These include:

1. Host-to-host communication: ARPANET was the first network to allow direct communication between computers rather than requiring all traffic to pass through a central hub.
2. End-to-end principle: ARPANET was designed to be a simple and robust system, with most of the intelligence and complexity located at the endpoints (i.e., the individual computers) rather than the network itself.
3. Protocol layering: ARPANET was the first network to use a layered protocol stack, with each layer responsible for a different aspect of network communication.
4. TCP/IP protocol suite: ARPANET was the first network to use the TCP/IP protocol suite, which remains an indispensable standard of internet communication even today.

Although ARPANET was eventually decommissioned in 1990, its architectural legacy continues to influence how we design and build computer networks today.

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Features of ARPANET

ARPANET had several key features that made it unique and innovative for its time. Here are some of the main features of the network:

ARPANET Features

1. Packet switching

ARPANET was the first operational packet-switching network. In packet switching, information is divided into small packets and sent separately across the network. This method of communication allowed multiple computers to share the same communication lines, making the transmission of data faster and more efficient.

Before packet switching, most communication networks used circuit switching, requiring a dedicated communication line to be established between two devices. Packet switching revolutionized communication networks and paved the way for the internet-enabled world.

2. Decentralized network architecture

ARPANET used a decentralized network architecture that allowed each computer on the network to communicate with several others. This made the network more resilient to failures and allowed information to be routed around damaged or congested areas. The decentralized architecture of ARPANET was achieved using routers, which were used to direct data packets to their intended destinations. The routers on ARPANET were designed to be intelligent and adaptable, which made the network more flexible and able to handle a wide range of traffic conditions.

Today, decentralized networks are used for various purposes, including file sharing, cryptocurrency transactions, and distributed applications. Moreover, blockchain technology relies on a decentralized ledger to record transactions and maintain consensus across the network. Decentralized network architecture has gained popularity in recent years due to its potential for greater security, privacy, and autonomy than centralized networks.

3. Resource Sharing

One of the primary objectives of ARPANET was to allow researchers to share resources such as computer programs, data sets, and processing power. This was achieved by developing protocols that allowed users to access remote resources as if they were local. For example, the Remote Job Entry (RJE) protocol allowed users to submit jobs to remote computers and receive the results back over the network.

Today, resource sharing continues to be an essential feature of networks and the internet, with a wide range of technologies and protocols used to share computing resources, including cloud computing, virtualization, and distributed computing systems.

4. Email

ARPANET was the first network to support email communication. The first email message was sent in 1971 by Ray Tomlinson, a computer engineer working on the network at the time. Email communication quickly became one of ARPANET’s most popular uses, allowing researchers to communicate more efficiently than ever before. The email protocols developed for ARPANET paved the way for today’s email systems.

In addition to email, ARPANET helped develop new network security technologies, such as firewalls, which are still used today to protect networks from unauthorized access and cyberattacks.

5. File transfer

ARPANET also supported file transfer protocols that allowed users to upload and download files from remote locations. The File Transfer Protocol (FTP) was developed for ARPANET and allowed users to transfer files between remote computers over the network. FTP quickly became one of ARPANET’s most popular uses, allowing researchers to share data and collaborate more effectively.

6. Remote login

ARPANET allowed users to log in to remote computers and use them as if they were local physical machines. This was achieved through the development of remote login protocols such as Telnet. It allowed users to access remote computers and use them with ease. This was a significant breakthrough for researchers who needed to access powerful computers and resources in remote locations. It eventually led to the development of remote access technologies such as virtual private networks (VPNs) and cloud computing.

7. Error correction

Error correction was a critical feature of ARPANET, ensuring that data transmitted across the network was received correctly and without errors. ARPANET used a technique known as Automatic Repeat reQuest (ARQ), which enabled error detection and correction at the data link layer of the network protocol.

When data was transmitted across the network, it was broken into packets, each with its own header containing information such as the destination address and the sequence number. As packets were received at the destination, they were checked for errors using a checksum, which was generated based on the contents of the packet. If an error were detected, the receiving node would request the packet be retransmitted, and the sender would resend it until it was received correctly.

This error correction process was critical to ensure data was transmitted accurately and reliably across the network. Without error correction, data transmitted over the network could be corrupted or lost, leading to data loss or inaccuracies in the information being transmitted.

Today, error correction continues to be an essential feature of network protocols, and more advanced error correction techniques have been developed to ensure the reliable transmission of data over high-speed networks. These techniques include Forward Error Correction (FEC), which adds redundant data to transmitted packets to enable the receiver to detect and correct errors, and Automatic Repeat reQuest with Selective Repeat (ARQ-SR), which enables the receiver to request retransmission of only the packets that were received with errors, rather than the entire packet stream.

8. Research and innovation

ARPANET was a research project designed to push the boundaries of what was possible with computer networking. As a result, it fostered a culture of innovation and experimentation that led to the development of technologies we take for granted today, including IoT, cybersecurity, telemedicine, ecommerce, social media, online collaboration tools, etc.

Importance of ARPANET

ARPANET was important for different walks of life in many ways, enabling innovation, collaboration, and communication on a global scale. Its impact on the world has been far-reaching and continues to shape how we live and work today. Let’s understand the importance of ARPANET in different fields.

1. Science and research

ARPANET enabled researchers and scientists to collaborate and share data, leading to significant advancements in various fields. For instance, in the 1970s, scientists used ARPANET to share data and collaborate on research projects related to the human genome. This collaboration led to the development of the first automated DNA sequencing machine, which paved the way for modern genetic research.

Additionally, in the 1970s, ARPANET was used to connect geographically spread laboratories working on developing the Large Hadron Collider (LHC), the world’s largest particle accelerator. The LHC project involved thousands of scientists and engineers from over 100 countries, who used ARPANET to share data and collaborate on the project.

2. Education

ARPANET played a critical role in advancing education by enabling remote access to resources like supercomputers, databases, and other scientific instruments. For example, in the 1980s, ARPANET enabled researchers at the University of California, Berkeley, to remotely access a supercomputer at the ‘Lawrence Livermore National Laboratory.’ This enabled researchers to conduct simulations and experiments that would have been impossible without the network.

3. Business and commerce

ARPANET significantly impacted business by enabling remote access to resources, making it easier for companies to conduct research, share data, and collaborate with partners and customers across different locations. In the 1980s, IBM used ARPANET to develop a remote ordering system for customers. This system enabled customers to order IBM products from any location with an ARPANET connection.

Moreover, in the 1980s, ‘American Airlines’ used ARPANET to develop a reservation system that allowed customers to book flights from remote locations. This system was the precursor to modern-day online booking systems used by airlines and other travel-related businesses.

4. Government

ARPANET had a quantifiable impact on the government by enabling remote access to resources and facilitating communication between different agencies and departments. For instance, in the 1980s, the U.S. Department of Defense used ARPANET to develop a system to share satellite data between different military agencies. This system enabled the military to coordinate and respond to threats more effectively.

5. Social life

ARPANET revolutionized social life by enabling people to communicate with each other across different locations and time zones. In the 1970s, ARPANET enabled a group of computer enthusiasts to develop a multi-user game called ‘Maze War.’ This game allowed players to connect to ARPANET from different locations and play together in a virtual environment, paving the way for modern online gaming.

6. Healthcare

ARPANET significantly impacted healthcare by enabling remote access to medical resources, making it easier for doctors and researchers to collaborate and share data. In the 1970s, ARPANET enabled doctors at the University of Pittsburgh to remotely access medical records and images from a hospital in Maryland. This collaboration led to significant advancements in medical research and patient care.

7. Defense

ARPANET played a vital role in the defense sector by enabling secure communication and collaboration between different military agencies and departments. In the 1970s, ARPANET enabled the U.S. military to develop a secure messaging system called ‘E-mail’ that could be used to communicate sensitive information between different agencies.

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Takeaway

ARPANET laid the foundation for a connected world, and its legacy continues to drive the development of technologies that enable us to be more connected than ever before. Its building blocks, such as packet switching, TCP/IP, email, and remote access technologies, have enabled real-time communication and collaboration, secure data transmission and storage, remote access and mobility, and a fertile ground for innovation.

These ARPANET components will continue to be the driving force behind the development of new technologies, such as 5G, edge computing, IoT, and AI, which will further connect people, devices, and systems. As a result, we will have a more interconnected world where individuals, organizations, and communities can work together seamlessly and efficiently, improving our lives in countless ways.

The U.S. Advanced Research Projects Agency Network (ARPANET) was the first public packet-switched computer network. It was first used in 1969 and finally decommissioned in 1989. ARPANET’s main use was for academic and research purposes.

Many of the protocols used by computer networks today were developed for ARPANET, and it is considered the forerunner of the modern internet.

Advanced Research Projects Agency Network (ARPANET)

The Advanced Research Projects Agency Network (ARPANET), the forerunner of the Internet, was a pioneering long-haul network funded by the U.S. Department of Defense’s Advanced Research Projects Agency (ARPA). It served as the test bed for many areas of internetworking technology development and testing, and acted as the central backbone during the development of the Internet. The ARPANET was built using packet-switching computers interconnected by leased lines.

In January 1969, the Advanced Research Projects Agency of the Department of Defense (ARPA) awarded a contract to Bolt, Beranek and Newman (BBN) to design and construct a communications network. By the end of 1969, an experimental ARPANET was operational between four university nodes. This system was the forerunner of the Internet.

Packet switching was developed independently by RAND researcher Paul Baran and British scientist Donald Davies. It is a communication method that took all kinds of data, queued it up, and packaged it into blocks that were sent together as a stream.

Lawrence Roberts, the ARPANET program manager, recognized that packet switching, which used a variable stream of data, would more effectively transmit data among a network of computers than circuit switching, which demanded a constant rate and led to delay.

Meanwhile, BBN, formed by MIT faculty members Richard H. Bolt, Leo Beranek, and Robert B. Newman, expanded from its initial specialty into acoustics into computers in the late 1950s. BBN bought Digital Corporation’s first PDP-1 and used it to develop computer solutions to hospital care. Working for the National Institutes of Health and Massachusetts General Hospital, BNN used the PDP-1 to build the first time sharing system, which allowed four simultaneous users to work on one computer.