Network Control Protocol (NCP)

Network Control Protocol (NCP) is a set of protocols forming a part of Point-to-Point Protocol (PPP). PPP is a data link layer protocol that is used to transmit multiprotocol data between two directly connected (point-to-point) computers. PPP is composed of Link Control Protocol (LCP), Authentication Protocol (AP), and Network Control Protocol (NCP).

NCPs are used for negotiating the parameters and facilities for the network layer. For every higher-layer protocol supported by PPP, one corresponding NCP is implemented to handle its specific configuration requirements.

How NCP Works

NCPs operate at the network layer within the PPP framework. They handle protocol-specific configuration after the basic PPP link has been established by LCP and authentication has been completed. Each NCP is responsible for configuring, enabling, and disabling its associated network protocol modules.

List of NCPs

• Internet Protocol Control Protocol (IPCP) − IPCP establishes and configures Internet Protocol (IP) over a PPP link. It configures the IP addresses in addition to enabling/disabling IP protocol modules on either end of the PPP link.

• OSI Network Layer Control Protocol (OSINLCP) − The responsibilities of OSINLCP include configuring, enabling and disabling the OSI protocol modules on either end of the PPP link.

• Internetwork Packet Exchange Control Protocol (IPXCP) − IPXCP is responsible for configuring, enabling and disabling the Internet Packet Exchange (IPX) modules on either end of the PPP link.

• DECnet Phase IV Control Protocol (DNCP) − This is responsible for establishing and configuring Digital's DNA Phase IV Routing protocol (DECnet Phase IV) modules over PPP link.

• NetBIOS Frames Control Protocol (NBFCP) − NetBIOS Frames (NBF) protocol is a non-routable network layer protocol. NBFCP is responsible for configuring, enabling, and disabling the NBF protocol modules on either ends of the PPP link.

• IPv6 Control Protocol (IPV6CP) − IPV6CP configures the IPv6 addresses. Besides, it enables and disables IPv6 protocol modules over PPP.

Key Features

• Protocol-specific configuration − Each NCP handles the unique requirements of its associated network protocol.

• Dynamic negotiation − NCPs negotiate parameters like IP addresses, compression options, and protocol-specific settings.

• Independent operation − Multiple NCPs can operate simultaneously on a single PPP link, enabling support for multiple network protocols.

Conclusion

Network Control Protocols are essential components of PPP that handle network layer protocol configuration. Each NCP manages the specific requirements of its associated protocol, enabling PPP to support multiple network layer protocols simultaneously over point-to-point connections.