CS 621 Lecture Notes - Simple Mail Transfer Protocol, Hypertext Transfer Protocol, Ethertype
Document Summary
Networks need modularity: the network does much for apps, make and break connections. Protocols and layers (3: protocols are horizontal, layers are vertical. Protocols and layers (4: set of protocols in use is called a protocol stack. Protocols and layers (5: protocols you"ve probably heard of, tcp, ip, 802. 11, ethernet, http, ssl, dns, Protocols and layers (6: protocols you"ve probably heard of, tcp, ip, 802. 11, ethernet, http, ssl, dns, And many more: an example protocol stack, used by a web browser on a host that is wirelessly connected to the internet. Encapsulation (3: message on the wire begins to look like an onion, lower layers are outermost. Encapsulation (5: normally draw message like this, each layer adds its own header. Last bits: more involved in practice, trailers as well as headers, encrypt/compress contents, segmentation (divide long message) and reassembly. Demultiplexing: incoming message must be passed to the protocols that it uses. Demultiplexing (2: done with demultiplexing keys in the headers.
