I'm reading about higher-level protocols such as HTTP and SOAP (concerning the application layer at the highest level) in addition to lower-level ones such as TCP. So far these protocols concern only one layer of the OSI model. For example SOAP talks about application layer specific elements such as type of files to transfer (XML only).
Do any protocols stretch over multiple layers? I could use HTTP with TCP or UDP (my application layer protocol is independent of my transport layer one), but are there any protocols that force another layer's communication to be changed?