Network Control Protocol


Network Control Protocol (NCP) is a set of protocols that establish and maintain communication between devices within a computer network. It helps manage and operate the data link layer of the network, controlling how data is transmitted and received across devices. NCP was primarily used in early ARPANET, the precursor to the modern internet, before being replaced by the more versatile Transmission Control Protocol/Internet Protocol (TCP/IP).

Key Takeaways

  1. Network Control Protocol (NCP) is an early networking protocol developed in the 1970s for ARPANET, the precursor to today’s internet. It was used to establish connections, facilitate reliable communication, and manage routing between computers.
  2. NCP provided the foundation for host-to-host interactions and enabled the exchange of data between different computer systems within ARPANET. It served as the basis for the development of the more advanced Transmission Control Protocol (TCP) and Internet Protocol (IP) suite, known as TCP/IP.
  3. Today, NCP is considered obsolete and has been replaced by more advanced and efficient networking protocols, mainly TCP/IP. However, it remains an essential part of internet history and paved the way for modern internet communication as we know it.


The technology term “Network Control Protocol” (NCP) is important because it played a crucial role in the early development of computer networking and the Internet as we know it today.

Established as a standard in the 1970s, NCP was the initial communication protocol used in the ARPANET (Advanced Research Projects Agency Network), which was the first large-scale packet-switched network and the precursor to the modern Internet.

NCP facilitated the efficient exchange of data and established connections between computers, effectively forming a foundation for the evolution of subsequent networking protocols, ultimately leading to the development of TCP/IP.

Although NCP has long been replaced by more advanced protocols, its significance lies in the groundwork it laid for today’s global communications infrastructure.


Network Control Protocol (NCP) serves a vital purpose in modern communication systems by establishing and maintaining solid network connections to facilitate the exchange of data among various devices.

First implemented as part of ARPANET in the early 1970s, NCP laid the groundwork for the development of more advanced protocols, such as the Transmission Control Protocol (TCP) and Internet Protocol (IP). As a core communication protocol, its primary responsibility is to enable computers and devices to connect and share information within a network.

To accomplish this, NCP ensures error-free data transmissions through efficient data routing and flow control between nodes.

Over the years, NCPs have evolved to fulfill the ever-growing needs of data-centered environments, becoming essential in modern network architectures such as Software-Defined Networking (SDN). In this context, the NCP functions as a crucial component that manages the complex communication paths within networks, allowing system administrators to maintain control over numerous aspects of network traffic, such as bandwidth allocation, data prioritization, and access controls.

As a result, NCPs contribute to improved network performance, better resource utilization, and enhanced data security by providing reliable and efficient data transmission for various applications and services.

Examples of Network Control Protocol

Network Control Protocol (NCP) refers to a communications protocol within a network that handles control information exchanged between nodes. It plays a crucial role in managing the overall performance and stability of the network. Here are three real-world examples related to NCP:

ARPANET NCP: The first major implementation of NCP happened in ARPANET, the precursor to the modern internet. ARPANET’s NCP enabled a host-to-host connection to establish reliable communications between computers. It served as the standard protocol until it was eventually replaced by TCP/IP in the early 1980s.

Point-to-Point Protocol (PPP) NCP: In the Point-to-Point Protocol (PPP) used in dial-up and leased line connections, Network Control Protocols are utilized to negotiate and establish network-layer protocols like IP, IPX, or AppleTalk, between the two PPP endpoints. Each network layer protocol used within the PPP connection has a corresponding NCP. For example, the IP Control Protocol (IPCP) is used for IP-based network layer protocols, and the AppleTalk Control Protocol (ATCP) is used for AppleTalk-based network layer protocols. These NCPs ensure proper negotiation and configuration among the connected devices.

Constrained Application Protocol (CoAP) NCP: In wireless sensor networks and IoT (Internet of Things) environments, the Constrained Application Protocol (CoAP) is a lightweight network protocol widely used for machine-to-machine (M2M) communication. CoAP incorporates an NCP-like mechanism in its Message layer to handle reliable message transactions, retransmissions, and flow control. This allows resource-constrained devices within IoT networks to communicate effectively and efficiently with each other and large-scale systems, ensuring optimal network performance.

Network Control Protocol FAQ

1. What is Network Control Protocol (NCP)?

Network Control Protocol (NCP) is a set of network protocols that were used in the early stages of the ARPANET – the precursor to the Internet. NCP was responsible for managing communication between hosts on the network, providing functions such as packet transmission, error checking, and addressing.

2. When was NCP used?

NCP was used in the ARPANET between 1969 and 1982. It was eventually replaced by the now widely-used Transmission Control Protocol (TCP) and Internet Protocol (IP) as part of the development of the modern internet.

3. What was the role of NCP in early networking?

In the ARPANET, NCP played a crucial role in establishing the foundation for modern networking. It was responsible for establishing connections between hosts, maintaining those connections, and transmitting data within the network. NCP also played a role in network addressing and error handling, allowing the nodes to communicate effectively with one another.

4. Why was NCP replaced?

NCP was replaced primarily due to its limitations and inability to scale with the growing size and complexity of the ARPANET. The development of TCP/IP introduced a more efficient and flexible set of protocols that could better handle the expanding network infrastructure, as well as support additional features, like error correction and congestion control, that were not initially part of NCP.

5. Can NCP still be used today?

While it is technically possible to use NCP in a private network, it is highly impractical due to the development and widespread adoption of more advanced and efficient networking protocols like TCP/IP. NCP is generally considered obsolete, and there is very little reason to implement it in a modern networking environment.

Related Technology Terms

  • Data Link Layer
  • Packet Switching
  • Transport Control Protocol (TCP)
  • Internet Protocol (IP)
  • Flow Control

Sources for More Information

  • Techopedia – A comprehensive technology dictionary and IT learning resource.
  • Network World – A platform dedicated to providing latest news, opinions, and resources for IT professionals in the domain of networking and data communication.
  • Computerworld – A source for technology news, analysis, and guidance targeted to IT professionals and decision makers.
  • IEEE Xplore – A digital library delivering full text access to quality technical literature in computer science, technology, and engineering fields.

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