Shoutbox

The purpose of the Internet layer is to select the best path through the network for packets to travel. The main protocol that functions at this layer is IP. Best path determination and packet switching occur at this layer.

The following protocols operate at the TCP/IP Internet layer:

• IP provides connectionless, best-effort delivery routing of packets. IP is not concerned with the content of the packets but looks for a path to the destination.
• Internet Control Message Protocol (ICMP) provides control and messaging capabilities.
• Address Resolution Protocol (ARP) determines the data link layer address, or MAC address, for known IP addresses.
• Reverse Address Resolution Protocol (RARP) determines the IP address for a known MAC address.
IP performs the following operations:
• Defines a packet and an addressing scheme
• Transfers data between the Internet layer and network access layer
• Routes packets to remote hosts

IP is sometimes referred to as an unreliable protocol. This does not mean that IP will not accurately deliver data across a network. IP is unreliable because it does not perform error checking and correction. That function is handled by upper layer protocols from the transport or application layers.