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Network Layer Protocols

Network Layer is responsible for the transmission of data or communication from one host to another host connected in a network. Rather than describing how data is transferred, it implements the technique for efficient transmission. In order to provide efficient communication protocols are used at the network layer. The data is being grouped into packets or in the case of extremely large data it is divided into smaller sub packets. Each protocol used has specific features and advantages. The below article covers in detail the protocols used at the network layer.

Functions of Network Layer

The network layer is responsible for providing the below-given tasks:

Network Layer Protocols

There are various protocols used in the network layer. Each protocol is used for a different task. Below are the protocols used in the network layer: 

Protocols at each Layer

1. IP (Internet Protocol)

IP stands for Internet Protocol. Internet Protocol helps to uniquely identify each device on the network. Internet protocol is responsible for transferring the data from one node to another node in the network. Internet protocol is a connectionless protocol therefore it does not guarantee the delivery of data. For the successful delivery higher level protocols such as TCP are used to guarantee the data transmission. The Internet Protocol is divided in two types. They are:

Difference between IPv4 and IPv6: IPv4 vs IPv6

2. ARP (Address Resolution Protocol)

ARP stands for Address Resolution Protocol. ARP is used to convert the logical address ie. IP address into physical address ie. MAC address. While communicating with other nodes, it is necessary to know the MAC address or physical address of the destination node. If any of the node in a network wants to know the physical address of another node in the same network, the host then sends an ARP query packet. This ARP query packet consists of IP address and MAC address of source host and only the IP address of destination host. This ARP packet is then received to every node present in the network. The node with its own IP address recognises it and sends it MAC address to the requesting node. But sending and receiving such packets to know the MAC address of destination node it increases the traffic load. Therefore in order to reduce this traffic and improve the performance, the systems that makes use of ARP maintain a cache of recently acquired IP into MAC address bindings.

How Does ARP Work?


Types of ARP Entries


RARP stands for Reverse Address Resolution Protocol. RARP works opposite of ARP. Reverse Address Resolution Protocol is used to convert MAC address ie. physical address into IP address ie. logical address. RARP provides with a feature for the systems and applications to get their own IP address from a DNS( Domain Name System) or router. This type of resolution is required for various tasks such as executing reverse DNS lookup. As Reverse Address Resolution Protocol works at low level it requires direct network addresses. The reply from the server mostly carries a small information but the 32 bit internet address is used and it does not exploit the full potential of a network such as ethernet.

How Does RARP Work?


Difference between ARP and RARP: ARP vs RARP


ICMP stands for Internet Control Message Protocol. ICMP is a part of IP protocol suite. ICMP is an error reporting and network diagnostic protocol. Feedback in the network is reported to the designated host. Meanwhile, if any kind of error occur it is then reported to ICMP. ICMP protocol consists of many error reporting and diagnostic messages. ICMP protocol handles various kinds of errors such as time exceeded, redirection, source quench, destination unreachable, parameter problems etc. The messages in ICMP are divided into two types. They are given below:

How Does ICMP Work?



IGMP stands for Internet Group Message Protocol. IGMP is a multicasting communication protocol. It utilizes the resources efficiently while broadcasting the messages and data packets. IGMP is also a protocol used by TCP/IP. Other hosts connected in the network and routers makes use of IGMP for multicasting communication that have IP networks. In many networks multicast routers are used in order to transmit the messages to all the nodes. Multicast routers therefore receives large number of packets that needs to be sent. But to broadcast this packets is difficult as it would increase the overall network load. Therefore IGMP helps the multicast routers by addressing them while broadcasting. As multicast communication consists of more than one senders and receivers the Internet Group Message Protocol is majorly used in various applications such as streaming media, web conference tools, games, etc.

How Does IGMP Work?

Difference between ICMP and IGMP: ICMP vs IGMP

Frequesntly Asked Question on Network Layer Protocols – FAQs

Is Transmission Control Protocol(TCP) a network layer protocol?

No, TCP is a transport layer protocol. TCP provides with a reliable connection between all the applications. Data is being sent from one host to another without any error and duplication issues.

Which layer protocols are designed for end- users?

Application layer protocols are designed for end-users. Application layer consists of protocols such as HTTP, HTTPS, FTP, SMTP, SSH etc.

State the format of ICMP message?

The ICMP message is of 32 bit. It consists of 3 fields. First field is of 8 bit that states type of message, second field is of 8 bit that states the reason of message and the third field is of 16 but that consists of actual ICMP message.

What is CIDR?

CIDR stands for Classless Inter-Domain Routing , it is basically addressing type which allows more effective and efficient use of IP address.

What is NAT?

Network Address Translation (NAT) is a process in which one or more local IP address is translated into one or more Global IP address and vice versa in order to provide Internet access to the local hosts.

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