Chapter 4

TCP/IP Core Protocols


Certain subprotocols of the TCP/IP suite, called TCP/IP core protocols, operate in the Transport or Network layers of the OSI model and provide basic services to protocols in other
layers. TCP and IP are the most significant protocols in the TCP/IP suite.


-TCP (Transmission Control Protocol) -  belongs to the Transport layer and provides reliable data delivery services.

-UDP (User Datagram Protocol) - sits in the Transport layer of the OSI model. UDP is a connectionless transport service.

-ICMP (Internet Control Message Protocol) -  notifies the sender that something has gone wrong in the transmission process and that packets were
not delivered.

-IGMP (Internet Group Management Protocol) - used to manage multicast transmissions. Routers use IGMP to determine which nodes belong to a multicast group, and nodes use IGMP to join or leave a multicast
group.

-IP (Internet Protocol) - belongs to the Network layer of the OSI model. It provides information about how and where data should be delivered, including the data's source and destination address. IP is the subprotocol that enables TCP/IP to traverse more than one LAN segment and more than one type of network through a router.

-ARP (Address Resolution Protocol) - that belongs in the Network layer of the OSI model. ARP obtains the MAC (physical) address of a host, or node, and then creates a local database that maps the MAC address to the host’s IP (logical) address.

-RARP (Reverse Address Resolution Protocol) - belongs in the Network layer of the OSI model. RARP relies on a RARP table to associate the IP (logical) address of a node with its MAC (physical) address. RARP can be used to supply IP addresses to diskless workstations.