Network Layer Protocols in OSI Reference Model
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:
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:
*IPv4: IPv4 provides with the 32 bit address scheme. IPv4 addressing has four numeric fields and are separated by dot. IPv4 can be configured either using DHCP or manually. IPv4 does not provide with more security features as it does not support authentication or encryption techniques. IPv4 is further divided into five classes as Class A, Class B, Class C, Class D and Class E.
*IPv6: IPv6 is the most recent version of IP. If provided with a 128 bit addressing scheme. IP address has eight fields that are separated by colon, and these fields are alphanumeric. The IPv6 address is represented in hexadecimal. IPv6 provides with more security features such as authentication and encryption. IPv6 supports end-to-end connection integrity. IPv6 provides with more range of IP address as compared to IPv4.
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.
3. RARP
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.
4. ICMP
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.
.
5. IGMP
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.