Network Control Protocol (NCP) was an early ARPANET protocol that enabled host-to-host communication, file transfer, and remote access before being replaced by TCP/IP.
- Used in ARPANET(Advanced Research Projects Agency Network)
- Supported simplex (unidirectional) communication
- Enabled remote computer access and file transfer
- Allowed multiple protocols to share the same serial link
- Replaced by TCP/IP in the 1980s
Protocols in NCP
Below are the protocols in NCP:
- Encryption Control Protocol (ECP): Manages encryption settings
- Compression Control Protocol (CCP): Handles data compression
- Bridging Control Protocol (BCP): Supports network bridging
- Internet Protocol Control Protocol (IPCP): Configures IP addresses
- OSINLCP: Controls OSI network layer modules
- IPXCP: Manages IPX protocol modules
- IPv6CP: Configures IPv6 over PPP
- NBFCP: Controls NetBIOS Frames protocol

Some of the common examples of NCP protocol are:
- Internet Protocol Control Protocol (IPCP): IPCP's main task is the configuration of the IP addresses over a point-to-point link. LCP or Link control protocol and IPCP of them use exact packet exchange mechanisms.
- OSI Network Layer Control Protocol (OSINLCP): OSI protocol modules are configured, enabled and disabled by OSINLCP on either end of the PPP link.
- Internetwork Packet Exchange Control Protocol (IPXCP): Internet Packet Exchange (IPX) modules on either end of the PPP link are configured, enabled, and disabled with the help of IPXCP.
- IPv6 Control Protocol (IPV6CP): It helps in the configuration of the IPv6 addresses it also enables and disables IP protocol modules over PPP.
- NetBIOS Frames Control Protocol (NBFCP): NBF protocol modules on either end of the PPP link are configured, enabled and disabled by NBFCP.
Advantages
- Network Configuration: NCP provides a standard protocol for configuring and maintaining network connections, which allows for easier and more consistent network management.
- Compatibility: NCP is designed to be compatible with multiple network types and technologies, including packet-switched, circuit-switched, and dedicated networks.
- Error Detection and Correction: NCP provides mechanisms for detecting and correcting errors in network connections, ensuring reliable and stable network performance.
- Flow Control: NCP provides flow control mechanisms to regulate the flow of data between the computer and the network, ensuring efficient and stable network performance.
- Compression: NCP can provide data compression, reducing the amount of data that needs to be transmitted over the network, increasing network efficiency and reducing network congestion.
Applications
- Wide Area Networking: NCP can be used to configure and manage wide area network (WAN) connections, including leased lines, satellite links, and other long-distance connections.
- Virtual Private Networks (VPNs): NCP can be used to establish and manage virtual private network (VPN) connections, allowing for secure and private communication over public networks.
- Internet Service Providers (ISPs): NCP can be used by ISPs to manage network connections for customers, allowing for efficient and effective network management and maintenance.
- Network Management: NCP can be used for network management purposes, providing a standard protocol for monitoring, configuring, and maintaining network connections.