IP is a best-effort, connectionless protocol that routes packets from source to destination using a logical IP address. The original RFC for IP was written in 1981, as seen at https://tools.ietf.org/html/rfc791. IP was standardized shortly after that.

Many of the original protocols in the TCP/IP suite have had minor changes, updates, and modifications over the years. However, IP had to make a major change, which was mainly due to a lack of address space. As a result, there are two versions of IP: IPv4 and IPv6. The following outlines a brief comparison of the two:

• IPv4 has a 32-bit address space. The use of private IP addresses has extended IPv4's lifespan on a LAN, but there is a slow migration to IPv6.
• IPv6 has a 128-bit address space and enhancements to the protocol in general, such as simplified network configuration and more efficient routing.

Next, we will look at ARP, which resolves an IP address to a MAC address.