IP-protocol Explanation


Internet Protocol or IP (or Internet Protocol according to abbreviationfinder) is a connectionless protocol used by both the source and the destination for data communication through a packet-switched network.

The Internet Protocol Family

It is a set of network protocols on which the Internet is based and that allow the transmission of data between computer networks. It is sometimes called the TCP/IP suite of protocols, referring to the two most important protocols that comprise it: Transmission Control Protocol (TCP) and Internet Protocol (IP), which were the first two to be defined, and which They are the most used of the family.

There are so many protocols in this set that there are more than 100 different ones, among them is the popular HTTP (HyperText Transfer Protocol), which is the one used to access web pages, as well as others such as ARP (Address Resolution Protocol) for address resolution, FTP (File Transfer Protocol) for file transfer, and SMTP (Simple Mail Transfer Protocol) and POP (Post Office Protocol) for email, TELNET to access remote computers, among others.


The IP protocol is the fundamental basis of the Internet. It carries datagrams from the source to the destination. The transport layer breaks the data stream into datagrams. During transmission, a datagram can be broken into fragments that are reassembled at the destination. The main characteristics of this protocol are:

  • Connectionless protocol.
  • Frag packets if necessary.
  • Addressing using 32-bit logical IP addresses.
  • If a packet is not received, it will remain on the network for a finite amount of time.
  • Do your “best effort” for package distribution.
  • Maximum packet size of 65635 bytes.
  • Checksum is performed only on the packet header, not on the data it contains.

The Internet protocol provides an unreliable, connectionless-oriented information packet distribution service. The non-connection orientation means that the information packets, which will be sent to the network, are treated independently, being able to travel through different paths to reach their destination. The term unreliable means more than anything that the reception of the packet is not guaranteed.


  • Data on an IP-based network is sent in blocks known as packets or datagrams (in the IP protocol these terms are often used interchangeably). In particular, in IP no configuration is needed before a computer tries to send packets to another that it had not communicated with before.
  • IP provides an unreliable datagram service (also called best effort, it will do the best it can but with little guarantee). IP does not provide any mechanism to determine whether or not a packet reaches its destination and only provides security (through checksums or checksums) of its headers and not of the data transmitted. For example, by not guaranteeing anything about the reception of the packet, it could arrive damaged, in a different order with respect to other packets, duplicate or simply not arrive. If reliability is needed, it is provided by transport layer protocols, such as TCP.
  • If the information to be transmitted (“datagrams”) exceeds the maximum size “negotiated” in the section of the network through which it is going to circulate, it can be divided into smaller packets, and later reassembled when necessary. These fragments can each go a different way depending on how congested the routes are at any given time.
  • The IP headers contain the addresses of the source and destination machines (IP addresses), addresses that will be used by the packet switches (switches) and the routers (routers) to decide the section of the network through which they will forward the packets.

IP address classes

They are divided according to the number of bytes that represent the network.

A class

In a class A IP address, the first byte represents the network.

The most significant bit (the first bit to the left) is zero, which means there are 2 7 (00000000 to 01111111) network possibilities, which is 128 possibilities. However, network 0 (bits with values ​​00000000) does not exist and the number 127 is reserved to indicate your team.

The available class A networks are, therefore, networks that go from to (the last bytes are zeros that indicate that it is surely a network and not computers).

In binary, a class A IP address looks like this:
0 Xxxxxxx Xxxxxxxxx Xxxxxxxxx Xxxxxxxxx
Network Computers

Class B

In a class B IP address, the first two bytes represent the network.

The first two bits are 1 and 0; this means that there are 214 (10 000000 00000000 to 10 111111 11111111) network possibilities, that is, 16,384 possible networks. The available Class B networks are therefore networks ranging from to

In binary, a class B IP address looks like this:
10 Xxxxxx Xxxxxxxxx Xxxxxxxxx Xxxxxxxxx
Network Computers

Class C

In a class C IP address, the first three bytes represent the network. The first three bits are 1,1 and 0; this means that there are 221 network possibilities, that is, 2,097,152. The available networks of the C classes are therefore networks ranging from to

In binary, a class C IP address looks like this:
110 Xxxxx Xxxxxxxxx Xxxxxxxxx Xxxxxxxxx
Network Computers


The purpose of dividing IP addresses into three classes A, B and C is to make it easier to find a computer on the network. In fact, with this notation it is possible to first search for the network that one wishes to have access to and then search for the equipment within this network. Therefore, the assignment of an IP address is done according to the size of the network.

Classification of IP addresses

Public IP

It is the IP address with which we identify ourselves when connecting to other networks (Internet). This IP is assigned to us by our ISP provider, and we have no control over it. In turn, it can be of two different types:

Static IP

It is when we have a fixed IP address assigned. This type is rarely used, it is of no interest to the home user and ISP providers usually charge a supplement for them.

Dynamic IP

It is the one commonly used. Our ISP provider assigns us when we connect to the network (Internet) an address that is available at that time. This address changes every time we disconnect from the Internet and reconnect.

Private IP

It is the IP address of each device (Introduction to Microcomputers|computer or any element that connects through the TCP/IP protocol) on our network. Contrary to what happens with the public IP, the private IP is assigned by us, although it can be assigned automatically (via DHCP). Those included in RFC 1918 are mainly used.

Advantages and disadvantages

  • The IP Protocol is designed for routing and has a very high degree of reliability, it is suitable for large and medium-sized networks, as well as enterprise networks. It is used globally to connect to the Internet and to web servers. It is compatible with standard tools for analyzing network performance.
  • One drawback is that it is more difficult to configure and maintain than NetBEUI or IPX/SPX; it is also somewhat slower on networks with a low average volume of traffic. However, it can be faster on networks with a high volume of traffic where a large number of frames have to be routed.
  • It is used both in corporate networks such as university campuses or business complexes, where many routers and connections to mainframe or UNIX computers are used, as well as in small or home networks, and even in mobile phones and home automation.

IP addressing and routing

Perhaps the most complex aspects of IP are addressing and routing. Addressing refers to how an IP address is assigned and how computers are subnetted and grouped together.
Routing consists of finding a path that connects one network with another and, although it is carried out by all the equipment, it is mainly carried out by routers, which are nothing more than computers specialized in receiving and sending packets through different network interfaces, as well such as providing security options, path redundancy and efficiency in the use of resources.

IP address

An IP address is a number that logically and hierarchically identifies an interface of a device (usually a computer) within a network that uses the Internet Protocol, which corresponds to the network level or level 3 of the model. OSI Reference. This number should not be confused with the MAC address, which is a physical number that is assigned to the network card or device (it is imposed by the manufacturer), while the IP address can be changed.

IP addresses can be expressed as numbers in decimal notation: the 32 bits of the address are divided into four octets. The decimal value of each octet can be between 0 and 255 [the highest 8-bit binary number is 11111111 and those bits, from right to left, have decimal values ​​of 1, 2, 4, 8, 16, 32, 64 and 128, which is 256 in total, 255 plus the 0 (0000 0000)]. In the decimal IPv4 address expression, each octet is separated by a single “.” character. Each of these octets can be between 0 and 255, with some exceptions. Leading zeros, if any, can be ignored ( would be It is common for a user who connects from home to the Internet use an IP address. This address can change on reconnect, and this form of IP address assignment is called a dynamic IP address (usually abbreviated as dynamic IP). internet sites that by their nature need to be permanently connected, generally have a fixed IP address (the same reduction for fixed IP or static IP applies); that is, it does not change over time. Mail servers, dns, public ftp, web servers, must necessarily have a fixed or static IP address, since in this way their location is facilitated. Machines have a great facility for manipulating and hierarchizing numerical information, and they are highly efficient at doing so and locating IP addresses. However, we humans must use another notation that is easier to remember and use; such is the case URLs and DNS domain name resolution.


In communications, routing (sometimes known by the anglicism routing or routing) is the mechanism by which information packets in a network are sent from their origin to their final destination, following a path or route through the network.. In a large network or in a set of interconnected networks, the path to follow to reach the final destination may involve passing through many intermediate nodes.
Associated with routing is the concept of a metric, which is a measure of how “good” it is to use a given path. The metric can be associated with different magnitudes: distance, cost, transmission delay, number of hops, etc., or even a combination of several magnitudes. If the metric is delay, a path whose total delay is less than another path is better. The ideal in a network is to achieve optimal routing: to have minimal distance paths (or cost, or delay, or whatever magnitude, depending on the metric). Routing is typically a function implemented at layer 3 (network layer) of the OSI reference model.

Future trends

IP is the common element in today’s Internet. The current and most popular network protocol is IPv4. IPv6 is the proposed successor to IPv4; Little by little, the Internet is running out of available addresses, so IPv6 uses 128-bit source and destination addresses (which assigns to each square millimeter of the Earth’s surface a colossal number of 670,000 million IP addresses), many more addresses than those provided by IPv4 with 32 bits. Versions 0 through 3 are either reserved or not used. Version 5 was used for an experimental protocol. Other numbers have been assigned, usually for experimental protocols, but have not been widely used.