Internet layer is responsible for logical transmission of data packets over the network, the main functions of the internet layer is to route each of the data packet independently from the source to the destination, using the optimal route. The internet layer includes the powerful IP, Address Resolution Protocol (ARP), and the Internet Control Message Protocol (ICMP).
Routing
The IP packets are transported through the network, hop by hop to the destination. The IP address is used to decide how to get the packet to the destination. There are two major classes of routing: LAN and WAN.
LAN routing
A LAN is usually a “broadcast” network in a shared medium (i.e. Wi-Fi), where multiple nodes can communicate with each other wirelessly, efficient communication is crucial. One important aspect is determining the destination address of a packet, the process is known as Address Resolution. There might be situation that the destination is not within a common LAN, the ARP has mechanism that tackles this scenario.
Addressing in Ethernet frames
Every Ethernet frame transmitted on the LAN includes the source MAC address (sender address) and the destination MAC address (receiver address) in the Ethernet header. To discover the destination MAC address of another node on the same LAN, devices uses a protocol called the Address Resolution Protocol (ARP)
WAN routing
The routers on the Internet uses dynamic routing ables that are maintained by edge systems (routers and network devices) communicating with each other. These dynamic routing tables are populated and updated using routing protocols, one of the key protocol is the Border Gateway Protocol (BGP).
Network Address Translation (NAT)
Private address ranges can be reused inside LANs, many thousands of LANs use the same range of addresses. If a computer wants to communicate outside the LAN that uses a private address range, the computer’s address has to be “translated” to a single non-private
IP address at your router.
Internet layer protocol
Internet Protocol (IP)
The IP is the principle component of the internet layer, it does not in charge with reliability or sequence of delivery, but focuses on getting packets to their destinations as efficiently as possible. The IPv4 uses 32-bit IP address whereas as the more recent IPv6 uses 128-bit. The IP protocol header contains the delivery address for the packet and its sender and more. (Details about IP on Internet Protocol (IP))
Address Resolution Protocol (ARP)
The ARP is used to resolve IP addresses to MAC addresses ensuring that data can be correctly delivered within the LAN. The ARP packet typically consists of hardware type, protocol type (IP version for IP addresses), operations (request and reply) and more. (Details about ARP on Address Resolution Protocol (ARP))
Internet Control Message Protocol (ICMP)
ICMP provides messages that indicate the status of a connection or error, it has a simple echo request to test if a host is responding. ICMP messages are placed inside the payload portion of an IP packet. (Details about ICMP on Internet Control Message Protocol (ICMP))
Back to parent node: Internet Protocol Suite
Computer_networksINFO1112IPInternet_layerEthernetLANWANNetwork_Address_Translation_NATInternet_Protocol_IPAddress_Resolution_Protocol_ARPInternet_Control_Message_Protocol_ICMPRouting