Internetwork Layer
The Internetwork layer in the TCP/IP model handles software, or logical, addressing. There are four main protocols functioning at this layer:
- IP: The Internet Protocol provides a connectionless delivery service. The IP moves packets around the network, including through routers.
- ICMP: The Internet Control Message Protocol provides message control and error-reporting services between two TCP/IP hosts or between a host server and a gateway to the Internet.
- ARP: The Address Resolution Protocol resolves IP addresses to MAC addresses. ARP is discussed in great detail in Chapter 4.
- RARP: The Reverse Address Resolution Protocol determines IP addresses from a RARP server. RARP is discussed in great detail in Chapter 4.