Internet Layer

Internet layer is the third layer in the TCP/IP model and is responsible for the transportation of network packets.

What Is an Internet Layer?

Internet layer is the third layer in the protocol stack of TCP/IP model. The internet layer is responsible for routing packets from one host to another through the network. This layer is considered to be the core of the design since it handles the transmission control and the datagram reassembly, which is required for communication to take place.

An internet layer is the top layer of the TCP/IP protocol suite, i.e., the network layer in the OSI model. This is also referred to as layer 3. It is responsible for the end-to-end delivery of data across interconnected networks, using IP addresses and routing information to direct packets to their destination.

Unlike other layers in the TCP/IP model, the Internet layer does not provide services directly to upper layers. Instead, it provides services to the next lower layer, the transport layer.

The Internet Protocol (IP) is probably most widely associated with this layer. IP is considered the core part of this layer as it handles basic communication functions such as creating packets, adding addressing information, and ensuring that packets are being sent to the correct location.

The second most important element at this level is the Internet Control Message Protocol (ICMP). ICMP works closely with IP to handle control and error messages between connected devices. Together, these two protocols help deliver content from one computer to another via an internet connection.

Internet Protocol version 4 (IPv4) has been widely used since 1981 and is now experiencing problems due to IPv4 address exhaustion; its replacement, IPv6, has been available since 1999 but has not yet been widely adopted by ISPs. 

The Internet Protocol Security (IPsec) protocol has also been widely implemented at this layer to provide security services, such as authentication and encryption across IP networks. Other protocols commonly seen at this level include Dynamic Host Configuration Protocol (DHCP), Domain Name System (DNS) and Windows Internet Naming Service.

The internet layer is often referred to as the network layer since it is responsible for logical addressing and routing. Logical addressing is done through the use of IP addresses. IP header comprises a 32-bit source address, a 32-bit destination address, a 16-bit type field, a 16-bit fragment flag, and a number of options fields. Headers can be either IPv4 or IPv6.

Network Layer vs. Internet Layer

The network layer is the level of the OSI model that handles communications between two different systems. It is responsible for packet routing, delivery, and error notification for computer messages.

In a way, a network layer is similar to an internet layer. However, an internet layer is responsible for routing packets from any one computer to another computer on a larger network, such as the internet. A network layer doesn’t care about who’s sending the message or where it’s going; it only cares about how to get it there.