#9 INTERNET PROTOCOL: THE NETWORKING SERIES

Are you online? Of course you are! And that’s how you are reading this blog right now. Would you like to know how this is possible? This series is all about what it takes to be online and access internet!

Hey peeps, hope now you are familiar with routing and basic networking concepts. But have you wondered how the packets that you are sending reaches its correct destination? And why not the packets reach the wrong destinations mostly? Yeah, everyone have thought of this at least once. Now here comes to play, “the Internet Protocol”.

We know that router is needed to get outside of your local network. But router alone cannot do the job. We need a proper IP address of source and destination. In this part we’ll be discussing about Internet Protocol. So, let’s dive into the topic!

Purpose of IPv4 Address

Let me start this with a simple example. Assume that you want to send a present for your friend on his birthday. But he is residing in another country or state, wherever. How do you send that present to your friend? Exactly, through mail/post. But if that present has to reach your friend, you must provide that present with a destination address, which is in this case, your friend’s home address. Take this example as reference, and compare this with our internet communication. If a packet that you are sending from your computer should reach a correct destination, then it should also has to have an address which is IP address. Unlike the normal address, IP addresses are like numbers (ex: 192.168.3.4).

A host needs an IPv4 address to participate in almost all LAN networks and on the internet. The IPv4 address is a logical address that helps to identify a particular host. The IPv4 address should be properly configured and unique within the LAN, for local communication and must be unique in the world, for remote communication. That is how a host is able to communicate with other devices and identified on the internet.

An IPv4 address is assigned to the network interface for a host. This is usually a Network interface card (NIC) installed in the device. Some devices or servers have more than one NIC, hence they have many IPv4 addresses which means that each of the NIC has its own IPv4 address. Router interface that provide connections to an IP network will also have an IPv4 address.

Every packet sent across the internet has a source and destination IPv4 address. This information is required by networking devices to make sure that the packets are sent to correct destination and any replies are returned to the source.

Photo by Leon Seibert on Unsplash

IPv4 in Binary

The IPv4 address is simply a series of 32 binary bits (1’s and 0's). There are over 4 billion possible IPv4 addresses using this 32-bit addressing scheme.

It will be very difficult to read an IPv4 address if it is in binary. It will be difficult for humans to read, write or remember. Hence, the 32 bits are grouped into four 8-bit bytes called octets and each octet is represented as its decimal value, separated by a decimal point.

For example, when a host is configured with an IPv4 address, it is entered as a dotted decimal number such as 192.168.1.5. But the actual 32-bit binary equivalent is 11000000101010000000000100000101. If you mistyped even one bit, then the address would be different, and we won’t be able to communicate the host on the network.

Each octet represents 1 byte which is 8 bytes. In the above case, each octet separated with space is represented as 11000000 10101000 00000001 00000101. Then each octet is converted into equivalent decimal value and instead of separating with space, as we did here for identification purpose, the decimal values are separated by a decimal point.

Let me conclude this part here! I’ll be writing about the structure of IPv4 address, Classes of IPv4 address and much more about unicast, multicast and broadcast networks.

Hope you enjoy this series! I’ll catch you up in the next part!

Stay connected!!

#7 OSI vs TCP/IP MODEL: THE NETWORKING SERIES

Are you online? Of course you are! And that’s how you are reading this blog right now. Would you like to know how this is possible? This series is all about what it takes to be online and access internet!

Hey peeps, you know how a network is constructed and how to configure a network. Continuing to this, we are going to discuss about the most popular networking models, “OSI Model” and “TCP/IP Model”. These models provide help us to visualize how the various protocols work together to enable network communications.

But, before moving into these models, let’s take a look at some of the common networking protocols.

  • Hypertext Transfer Protocol (HTTP): This governs the interaction between a web server and a web client. It defines the content and formatting of the requests and responses that are exchanged between the client and server.
  • Transmission Control Protocol (TCP): This protocol manages the individual conversations. TCP is responsible for guaranteeing the reliable delivery of information and controlling the flow between the end devices.
  • Internet Protocol (IP): This is responsible for delivering information from the sender to the receiver. It is used by routers to forward messages across multiple networks.
  • Ethernet: This protocol is responsible for the delivery of messages from one NIC to another NIC on the same Ethernet LAN.

The TCP/IP Model

The first layered model for internetwork communication was referred to as the internet model. It defines a four categories of function that is carried out during a communication in order to be successful. The suite of TCP/IP protocols used for internet communication follows the structure of this model. Hence, this model is known as “TCP/IP Model”.

Layers of TCP/IP Model

  • Application: Represents data to the user, encoding and dialog control
  • Transport: Enables communication between various devices across networks
  • Internet: Determines the best path through the network
  • Network Access: Controls hardware devices and media that make up the network

The OSI Model

This most widely known interconnection model was created by the Open Systems Interconnection (OSI) project at the ISO. It is used for data network design, operation specifications and troubleshooting.

Layers of OSI Model

  • Application: This layer contains protocols used for process-to-process communications.
  • Presentation: Provides common representation of the data transferred between application layer services.
  • Session: Provides services to presentation layer to organize its dialogue and to manage data exchange.
  • Transport: Responsible to segment, transfer and reassemble the data for individual communications between end devices.
  • Network: Provides services to exchange the individual pieces of data over the network.
  • Data Link: This layer protocols define the methods for exchanging data frames between devices over a common media.
  • Physical: Describes the physical connections for transmission of a bit from and to a network device.

The data transmission across a network can be easily visualized using the seven layers of the OSI model. The OSI model breaks down the network communications into multiple processes. Each process is a small part of a larger task.

OSI and TCP/IP Model Comparison

The TCP/IP model visualizes the interactions of various protocols that make up the TCP/IP protocol suite. It does not describe the general functions that are necessary for network communications. This model explains the networking functions that are specific to those protocols in use in the TCP/IP model. To illustrate, at the network access layer of TCP/IP model, it does not specify which protocol to use when transmitting over physical medium nor the encoding methods that are performed for transmission of the signals. Whereas, OSI Layer 1 and Layer 2 discuss the necessary procedures to access the media and the physical means for sending a data over a network.

The protocols that make up the TCP/IP protocol suite can be described in terms of the OSI reference model. Like, the functions that occur at the “internet layer” in the TCP/IP model is contained in the “network layer” of the OSI model. The “transport layer” functionality is same in both the models. However, the “network access layer” and “application layer” of the TCP/IP model is further divided into two layers in the OSI model.

Both TCP/IP and OSI models are commonly used when referring to protocols at various levels. However, while referring to lower levels, OSI model is preferred as it separates the “data link layer” from the “physical layer”.

Now, you are familiar with the common models used in network communications. I’ll catch you up in the next blog with another interesting topic!

Stay connected!!

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