TCP/IP

Transmission Control Protocol (TCP/IP) refers to the collection of networking protocols that have been used to construct the global Internet. 
The TCP/IP protocols were developed in the 1970s specifically for the use on a packet-switching network built by the United States Department of Defense, the network was known as ARPANET, but it is now the Internet.    
The Internet Engineering Task Force (IETF) publishes the TCP/IP standards in documents called Requests for Comments (RFCs). 

The Benefits of Using TCP/IP
TCP/IP enables cross-platform, or heterogeneous, networking and has the following characteristics:

• Good failure recovery
• The ability to add networks without interrupting existing services
• High error-rate handling
• Platform independence
• Low data overhead

The TCP/IP protocol is the standard and the most accepted networking protocol. 
TCP/IP protocols were developed before the OSI reference model, but both operate using the layers in the same way. 
Many TCP/IP application protocols were designed to access and transfer data between dissimilar systems. These protocols include HTTP, FTP and Telnet. Individual protocols make it easier to support a variety of computing platforms. 
TCP/IP has its own four layer networking model they are:

• Link 
• Internet
• Transport Layer
• Application Layer

Link Layer :

The TCP/IP protocol suite includes the link layer protocols like the Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP). However, it maintains a layer that is comparable to the OSI data-link layer. 

TCP/IP protocol includes Address Resolution Protocol (ARP) which functions at the link layer, because it provides services to the internet layer above it.

Internet Layer:

The Internet layer is the same as network layer of OSI model. This layer is responsible for routing and delivery of data across networks.

It allows communication across networks of the same and different types and carries out translations to deal with dissimilar data addressing schemes.

IP (Internet Protocol) and ARP (Address Resolution Protocol) are both to be found at the Internet layer, however IP is the primary protocol operating at this layer. 

Transport Layer :

The TCP/IP Transport layer is similar to that of OSI transport model, but with elements of the OSI session layer functionality. This layer provides an application layer delivery service.

The TCP is a reliable, connection-oriented protocol which provides error checking and flow control through a virtual link that it establishes and finally terminates.

This gives a reliable service, therefore TCP would be utilized by File Transfer Protocol (FTP) and Simple Network Management Protocol (SNMP). 

UDP is an unreliable, connectionless protocol which provides data transport with lower network traffic than TCP. 

Application Layer :

The Application layer of TCP/IP is broadly equivalent to the application, presentation and session layers of the OSI model. The protocols found at this layer are Telnet, FTP, SNMP, HTTP (Hyper Text Transfer Protocol) and SMTP (Simple Mail Transfer Protocol).

The protocols that operate at the various layers of TCP/IP protocol stack are:

• SLIP
• PPP
• ARP
• IP
• ICMP
• TCP
• UDP
• FTP
• HTTP

Internet Protocol (IP):

Short for Internet Protocol, IP is an address of a computer or other network device on a network using IP or TCP/IP. For example, the number "166.70.10.23" is an example of such an address. 

These addresses are similar to an addresses used on a house and is what allows data to reach the appropriate destination on a network and the Internet.

There are five classes of available IP ranges:

Class A, Class B, Class C, Class D and Class E, while only A, B, and C are commonly used. Each class allows for a range of valid IP addresses.

Getting an IP address:

By default the router you use will assign each of your computers their own IP address, often using NAT to forward the data coming from those computers to outside networks such as the Internet.

If you need to register an IP address that can be seen on the Internet, you must register through InterNIC or use a web host that can assign you addresses.

Anyone who connects to the Internet is assigned an IP address by their Internet Service Provider (ISP) who has registered a range of IP addresses.

Internet Protocol (IP) is responsible for carrying the data generated by all the other TCP/IP protocols from the source system to its ultimate destination. 

Internet Control Message Protocol (ICMP)

Internet Control Message Protocol (ICMP) is a protocol within the TCP/IP stacks which basically provides control, troubleshooting, and error messages.

It is considered to be an internet layer protocol and that it carries no application data and its messages are carried within IP datagrams.