Editing Internet protocol suite (section)

==Internet layer==
{{main article|Internet layer}}
[[Internetworking]] requires sending data from the source network to the destination network. This process is called [[routing]] and is supported by host addressing and identification using the hierarchical [[IP address]]ing system. The internet layer provides an unreliable datagram transmission facility between hosts located on potentially different IP networks by forwarding datagrams to an appropriate next-hop router for further relaying to its destination. The internet layer has the responsibility of sending packets across potentially multiple networks. With this functionality, the internet layer makes possible internetworking, the interworking of different IP networks, and it essentially establishes the Internet.

The internet layer does not distinguish between the various transport layer protocols. IP carries data for a variety of different [[upper layer protocol]]s. These protocols are each identified by a unique [[List of IP protocol numbers|protocol number]]: for example, [[Internet Control Message Protocol]] (ICMP) and [[Internet Group Management Protocol]] (IGMP) are protocols 1 and 2, respectively.

The Internet Protocol is the principal component of the internet layer, and it defines two addressing systems to identify network hosts and to locate them on the network. The original address system of the [[ARPANET]] and its successor, the Internet, is [[Internet Protocol version 4]] (IPv4). It uses a 32-bit [[IP address]] and is therefore capable of identifying approximately four billion hosts. This limitation was eliminated in 1998 by the standardization of [[Internet Protocol version 6]] (IPv6) which uses 128-bit addresses. IPv6 production implementations emerged in approximately 2006.