Of the seven layers in the OSI reference model, layer 3 corresponds to the network layer. There are some important network layer protocols that you need to know. The protocol is just a set of rules that determine how messages are exchanged between different computers.
Let us now briefly examine five important protocols related to the transfer of network layered messages. These are IPv4, IPv6, CLNP, IPSec and ICMP.
IPv4: IP stands for Internet Protocol, and v4 means version 4. Here, version 4 refers to the fourth revision of the later Internet Protocol. There is an IPv4 header structure that is the basis for the transfer of packets of network layers. This is one of the most important network layer protocols.
IPv6: It is also an Internet protocol with version 6. Although IPv4 is widely used today, it is expected that this IPv6 will gain the attention of others. This is why it is called the next generation protocol. There are some basic differences between the two protocols. IPv6 address space is larger than IPv4 address space.
CLNP: CLNP stands for Connectionless Network Protocol. The service provided by this protocol is called CLNS. This leads the messages to their destination independently.
IPSec: Internet Protocol Security is one of those protocols that enables the encryption and authentication of all IP packets that move in a data stream. Encryption and authentication are two techniques to ensure the secure transfer of messages from source to destination.
ICMP: ICMP is the Internet Control Message Protocol. This particular protocol is very important among all network layer protocols. This is used by network operating systems to send error messages indicating that a particular service was unavailable or that a connection to a router failed, and so on.