Internet (TCP/IP) protocol suite is an "open" network standard, which allows computers of all sizes, from different vendors and various kinds of operating systems to communicates each other. It is the most popular network protocol suite and the basis of the worldwide network, Internet.

Layering

Internet (TCP/IP) is normally considered to be a 4-layer system according to Richard Stevens and RFC1122.

The four layers are:

1. Link Layer: device driver with network interface card "andle hardware detail and physical connection. (ARP, RARP)

2. Network Layer (also called IP layer): use IP to handle packet movement, such as routing and messaging. (IP, ICMP, IGMP).

3. Transport Layer: provide data flow for the application layer. (TCP, UDP)

4. Application Layer: handle details of the application and provides interface to users. (FTP, SMTP, TFTP, BOOTP, SNMP, Telnet/Rlogin, NFS, DNS, etc.)

Each layer has one or more protocols to communicate with its peer at the same layer.

Protocols in one layer usually communicate with its adjacent layer.

Internet Protocols and Related RFCs

• ARP (Address Resolution Protocol), in Link Layer. A protocol to map from 32-bits IP addresses to 48-bits Ethernet (or Token Ring) addresses. ARP communicates with IP Layer.

  Related RFC: RFC 826, "An Ethernet Address Resolution Protocol, David C. Plummer, Nov. 1982."

• RARP (Reverse Address Resolution Protocol), a Link Layer protocol. Provides mapping from link layer addresses to IP addresses. Used for X terminal, diskless workstation, or network printer server, etc. Same as ARP, the layer above is IP Layer.

  Related RFC: RFC 903, "A Reverse Address Resolution Protocol, Mann, Mogul, Theimer, Jun. 1984."

• IP (Internet Protocol), of Network Layer. IP provides a connectionless, datagram delivery service. IP delivers datagram between TCP, UDP, ICMP, IGMP and Link Layer. The IP protocol includes provision for addressing, type-of-service specification, fragmentation and reassembly, and security information.

  Related RFC: RFC 791, "Internet Protocol, DARPA Internet Program, Sep. 1981."

• ICMP (Internet Control Message Protocol), is an integral part of IP, although it is layered upon IP. ICMP provides error reporting, congestion reporting, and first-hop gateway redirection. It communicates error messages or condition codes between IP Layer and TCP protocol or UDP protocol.

  Related RFC: RFC 792, "Internet Control Message Protocol, DARPA Internet Program, Sep. 1981."

• IGMP (Internet Group Management Protocol), is an IP layer protocol. IGMP manages multicast groups, which is used by hosts and routers that support multicasting. Like ICMP, IGMP transmits IP datagram between IP Layer and TCP protocol or UDP protocol.

  Related RFC: RFC 1112, "Host Extensions for IP Multicasting, S. Dearing, Aug. 1989."

• TCP (Transmission Control Protocol), of the transport layer, is a connection-oriented transport service that provides end-to-end reliability, resequencing and flow control. TCP transmits data segments of applications to IP Layer. Two most important TCP applications are Telnet and Rlogin.

  Related RFC: RFC 793, "Tranmission Control Protocol, DARPA Internet Program, Sep. 1981."

• UDP (User Datagram Protocol), of the transport layer, offers only a simple, connectionless (datagrams) transport service. It gives applications (such as multicast, or broadcast) direct access to the datagram service of the IP layer.

  Related RFC: RFC 768 , "User Datagram Protocol,J. Postel, Aug. 1980."

• FTP (File Transfer Protocol), of the application layer, is a primary Internet standard for file transfer. FTP uses separate simultaneous TCP connections for control and for data transfer.

  Related RFC: RFC 959 , File Trnasfer Protocol",J. Postel, Oct. 1985."

• SMTP (Simple Mail Transfer Protocol), an application protocol, specifies the Internet standard format for electronic mail messages.

  RFC 822 , Standard For The Format Of ARPA Internet Text Messages", David Croker, Aug. 1982."

• TFTP (Trivial File Transfer Protocol) , in application layer, provides a reliable delivery with UDP using stop-and-wait acknowledgment system, which providing no access control or security. TFTP's most important application is bootstrapping a host over a local network.

  Related RFCs:

  RFC 783 , The TFTP Protocol", K. R. Sollins, Jun. 1981."
  

  RFC 1350, The TFTP Protocol, K. Sollins, Jul. 1992."

• BOOTP (Bootstrap Protocol), is an application protocol allowing a host to determine the IP addresses of the local host and the boot server, the name of an appropriate boot file, and optionally the address mask and list of default gateways. The host broadcasts a BOOTP request using UDP to locate a BOOTP server.

  Related RFCs:

  RFC 951, Bootstrap Protocol", Bill Croft, Sep. 1985."
  

  RFC 10 84, BOOTP Vendor Information Extensions, J. Reynolds, Dec. 1988."
  

  RFC 15 42, Clarification and Extensions for the Bootstrap Protocol, W. Wimer, Oct. 1993."

• SNMP (Simple Network Management Protocol) is an application protocol used for managing various of systems on the Internet. SNMP communicates between network management manager and agents. It operates on a Management Information Base (MIB) that defines a collection of management values.

  Related RFCs:

  RFC 1155, Structure and Identification of Management Information for TCP/IP-based Internets, M. Rose, May. 1990."
  

  RFC 1157, A Simple Network Management Protocol, J. Case, May. 1990."
  

  RFC 1213, Management Information Base for Network Management of TCP/IP-based Internets, K. McCloghrie, Mar. 1991."

• Telnet, a standard Internet application protocol for remote login. It provides the encoding rules to link a user's keyboard/display on a client ("user") system with a command interpreter on a remote server system. Telnet uses a single TCP connections. Rlogin is a similar and simpler protocol for remote login.

  Related RFC: RFC 854, Telnet Protocol Specification, J. Postel, May. 1983."

• NFS (Network File System) is an RFC 1094, NFS: Network File System Protocol Specification, Sun Microsystems Inc., Mar. 1989."

• DNS (Domain Name System), translates between host names and IP addresses with a distributed database system.

  Related RFCs:

  RFC 10 34, Domain Names- Concepts and Facilities, P. Mockapetris, Nov. 1987."
  

  RFC 10 35, Domain Names - Implementation and Specification, P. Mockapetris, Nov. 1987.

Original Source available from Jerry Zang'sHome Page