English: Use of of the Internet protocol suite for communication between two applications on Internet hosts, from source host A towards destination host B. As shown on the top, hosts A and B are connected via two routers. The use of different layers of the Internet protocol suite on the hosts and the routers is shown at the bottom. Hosts and routers use the Internet layer to route packets via next hops solely based on the destination IP address, while only the hosts need the upper layers to send or receive application data. Protocols at the transport layer provide end-to-end communication services for applications, while the application layer accommodates protocols such as HTTP, SMTP, and DHCP, each of which relies on transport layer protocol services for end-to-end communication.