Internet protocols are needed for the proper functioning of the internet and it includes TCP, HTTP, UDP, FTP, protocols that interact with web browsers while, ARP, ICMP interact with network adapters (IC). Network Protocols are required for Wi-Fi, Bluetooth, and LTE to fully function. Network routing protocols are needed for the best download path for a device to download a file or data from the internet. These include EIGRP, OSPF, and BGP. This article will give you a quick introduction to TCP/IP – Transmission Control Protocol and Internet Protocol Suite.
TCP/IP
It is a collection of several protocols, but the core functionality of TCP/IP comes from two separate protocols working together, the so-called Transmission Control Protocol (TCP) and Internet Protocol (IP). The job of the TCP is to break up the data from the sending computer into small packets and get these packets ready for transmission. Each packet is given a sequence number at this stage. The content of each packet is used to calculate extra information which is then added to the packet as it’s been created the calculation is done again at the receiving end to check for corruption during transmission.
Transmission Control Protocol (TCP)
TCP on the receiving computer reassembles the packets in the correct order according to their sequence numbers and if there are any packets that have been damaged on the way or haven’t been received at all, TCP will request that those packets be sent again. You can see that the transmission control protocol is all about ensuring the integrity of the data.
- Breaks data into packets before sending
- Adds error checking information to packets
- Reassembles packets when received
- requests retransmission of failed packets
Internet Protocol (IP)
The Internet Protocol on the other hand will add addressing information to each packet information to each packet information to identify the intended recipient of the packets. This is the recipient’s so-called IP address. The sender’s IP address is also added to the packet. The IP addresses also indicate where the recipient and the sender are located. This information is used by the network routers to guarantees that the packets are being dispatched in the right direction.
- Identifies devices on the network
- Routes packets from source to destination via routers
Notes on IP Address:
- Each computer running TCP/IP must have an assigned unique IP address
- A 32-bit number expressed as 4 denary octets for convenient notation
- Computers can be statically or dynamically configured (DHCP)
- A subnet mask identifies the computer’s location on a segmented network
- default gateway’s IP address provides access to the wider network
TCP/IP Suite of Network Protocols
Other protocols that collectively provide the data transport services utilized by just about everything on the internet.
- HyperText Transfer Protocol (HTTP) – This is used over the world wide web, to deliver multimedia-rich webpages to your browser.
- File Transfer Protocol (FTP) – Can be used when you want to relocate files quickly between computers.
- Simple Mail Transfer Protocol (SMTP) – Used when email messages are sent between mail servers.
- Post Office Protocol (POP) – This comes into play when you retrieve email messages from a mail server so you can work with them locally on a PC-based application such as Outlook.
- Internet Message Access Protocol (IMAP) – allows you to work with mail live on the server using webmail systems such as Hotmail or Gmail.
- Voice Over Internet Protocol (VOIP) – This is specifically for transferring voice and video data over the internet allowing for telephone-style conversations. VOIP is itself a suite of programs.
- User Datagram Protocol (UDP) – A lightweight substitute to TCP. It is much less reliable than TCP because it does not perform any of the error checkings, but it is much faster. UDP is suitable for applications where the quality of transmission is not a big issue such as live video streams and online games.
- Internet Control Message Protocol (ICMP) – Utilized by routers to exchange status information and error messages. For example, to report that a particular route that cannot be reached.
- Address Resolution Protocol (ARP) – allows one device to discover another’s MAC address if its IP address is known. Once the target network segment has been reached, the MAC address comes into play.
Most TCP/IP packets begin and end their journey on a LAN using ethernet, but IP addresses can only get packets so far, the last leg of the journey depends on each packet bearing the destination MAC address.
How do these protocols work together to get data ready for network transmission?
For our example, let’s start with data we want to transmit, it might be a web page being delivered by a web server to a user’s browser. A file being copied from one machine to another.
To begin with, the data must be collected from the application software and formatted for further processing the protocols that perform this task includes – HTTP, FTP, SMTP, and POP3, dependent upon the quality of the data.
Then the data is fragmented down onto packets a sequence number and error-checking data is added to each packet. In addition, something called a “port number” is added to indicate the nature of the data and therefore the application it is heading for. This port number, in concept, is different from a physical port on a device that you plug a cable into. Port 80 means that it is HTTP data which is a web page, port 20 is delegated for FTP, while port 25 is SMTP data, and the list goes on. Port numbers are not only used by the receiving application but also by routers to control the movement of certain types of data in a process known as Port Forwarding. Packetizing the data is the job of the TCP.
The source and destination IP addresses are added to each packet, this is essential information for the routers. IP addressing information is added by the Internet Protocol (IP) or ICMP if it is control information.
Finally, the source and destination MAC addresses are added to each packet. MAC addresses are essential for ethernet communication on a LAN segment. Each IP packet is now enclosed within an ethernet frame. Imagine, as if it is a package inside a package. ARP is an example of a protocol that’s important when performing this task.
The four distinct layers of software, each layer with a name according to the job of the software operating at that layer. The Application Layer sits at the top, underneath is the Transport Layer, then the Network Layer, and finally the Link Layer at the bottom. This is the so-called four-layer model. The software at each layer can only communicate with what is directly above directly below. The interfaces between these layers now are the rules for passing data from one program to another are standardized and well-known. This means that software from manufacturers like Sun, Microsoft, Cisco, and the open-source community can write new programs to slot in at any position, confident about the compatibility of the programs.
TCP/IP Suite
It is a series of multi-step protocols that are meant and utilized for connection and communication across the internet. The standard of communication of this suite can be asserted as a client-server model. TCP/IP model is a layered implementation of that OSI, in this case, TCP/IP has 4 layers.
Layers of TCP/IP
- Application Layer
- Transport Layer
- Network Layer
- Data Link Layer
All the activities that were being done in the OSI physical model are being covered by these four layers themselves. TCP/IP is a client-server suite, which means the client is sending a request and a server machine is fulfilling that request. In the TCP/IP model, since it is an implementation of the OSI model, there will be different protocols at each level.
Application Layer
HTTP protocol or FTP protocols are used. HTTP – Hypertext Transfer Protocol is the most commonly used protocol for transferring text, whereas FTP or File Transfer Protocol is used for transferring files.
Transport Layer
This layer uses TCP or Transmission Control Protocol to establish the session between the client machine and the server machine.
Network Layer
This stage utilizes Internet Protocol. At this point, all the machines, all the workstations are the nodes even the servers are attached to the TCP/IP network is assigned an IP address. Whatever is the source desk or the destination address that is to be reflected in the form of the IP address. When the client is sending a request, it will give its own address and it will give the IP address of the server machine.
Data Link Layer
The last layer in this structure is where it actually transmits the data physically and it goes to the server machine at the server end again at the network layer that data is assembled until it passes through the entire TCP layers at the server end and the data is assembled completely.
