Networking Foundations (2): Network Protocols

In the first part of this series, we discussed the meaning, types, and various arrangements of computer networks. You can access it here. In this writeup, we delve into the technology that makes possible, the communication between devices or nodes in a network. The idea is simple: Once a set of conditions are met, data can be shared(or exchanged) between the network devices.

What is a network protocol?

A network protocol refers to the terms and conditions that govern how data is transferred between different devices in the same network. It is a set of rules that determine how network devices communicate on a given network. Network protocols facilitate interaction between different network-enabled devices e.g. laptops, tablets, servers, etc.

Before going further, we take a peek at some key terminologies vital for our discussion.

Network Address

A network address is a unique code or set of characters that identifies any given device in a network. Two common address types are the Media Access Control (MAC) address which identifies the device hardware, and the Internet Protocol (IP) address which identifies the device software.

Data Packet

This describes a unit of data transferred from one device to another in a network. Think of it as an envelope used to send a letter containing a specific type and amount of information. Each device in a network can send multiple data packets (i.e. envelopes) in sequence to another device in the network. In other words, data transfer within a network is said to be fragmented.

Furthermore, each data packet consists of a header and a trailer. The header includes sender and destination device addresses, the packet size, packet number, and the type of protocol. The trailer deals with error checking in the data packet.

Routing

Routing is a networking term that describes the mechanism used to ensure that data packets follow the right path from one device(sender) to another(receiver). In this context, to 'route' means to direct the flow of data between devices in a network.

Categories of Network Protocols

Various kinds of network protocols exist. For instance, the Hypertext Transfer Protocol (HTTP) is the protocol responsible for the exchange of web pages between a browser and a server.

Generally speaking, network protocols can be grouped into three broad categories:

  • Network communication protocols

  • Network security protocols

  • Network management protocols

Network communication protocols

These protocols create and maintain a connection between devices. The two foundational protocols upon which all internet-based networks are laid are described next.

Transmission Control Protocol (TCP)

TCP minimizes data loss by fragmenting data into data packets that can be sent securely and fast. Furthermore, the TCP port (number) indicates what type(class) of information is being sent. For example, port 25 is for Simple Mail Transfer Protocol (SMTP) i.e. the information being sent is an email.

Internet Protocol (IP)

IP is responsible for the addressing of a data packet. IP adds an address header containing information about the sender and recipient IP addresses.

Depending on the type of application or data sent, network communication protocols are grouped into the following:

Hypertext Transfer Protocol (HTTP)

HTTP is involved with the delivery of web page content from a server to your browser via TCP/IP.

File Transfer Protocol (FTP)

FTP is used for the exchange of files between different computers on a network.

Email Protocols

The email protocols are concerned with the sending and receiving of emails. The three main variants of email protocol are:

  • Post Office Protocol 3 (POP3)
  • Simple Mail Transfer Protocol (SMTP), and
  • Interactive Mail Access Protocol (IMAP).

Network security protocols

These protocols ensure the security of data connection across your networks. They guard network connections against potential attacks by encrypting messages between users, services, and applications. The leading network security protocols include:

Secure Socket Layer(SSL)

SSL is a standard protective protocol that provides security and encryption in the connection between your computer and the target server or devices that you accessed over the internet. Transport Layer Security (TLS) is the successor to SSL and offers a better security encryption protocol.

SSL and TLS are typically used to safeguard web browser communications, emails, instant messaging, and so on. This has led to more secure communication protocols like HTTPS, POPS, SMTPS, and IMAPS- where the last 'S' stands for secure.

Secure Shell (SSH)

SSH is similar in function to SSL but supports command-line execution of instructions such as remote authentication to servers. SSH is usually used in FTP connections.

Kerberos

Kerberos is a robust authentication service for client-server-type applications. It provides strong encryption for all communications and data at all times.

Network management protocols

It is usually possible to have multiple protocols running simultaneously in your network(s). Network management protocols help to detect faults and check performance in the running protocols. In other words, they monitor the networks and any devices attached to them.

Simple Network Management Protocol (SNMP)

Used by devices such as switches, routers, laptops, and servers, SNMP is an internet protocol that helps the collection of data from devices on your network and the management of those devices.

Internet Control Message Protocol (ICMP)

A part of the Internet Protocol Suite (IPS), ICMP allows devices on a network to send warning and error messages, or messages about the condition and availability of a service.

Conclusion

Knowledge of networking is vital for any aspect of IT. We have discussed networks as being made up of devices like PCs, routers, and switches. We have also peered into the various types and arrangements of networks available to choose from. Other concepts such as network communication and security protocols underpin how data is shared and protected on a network. It has well been a nice ride!