I passed my midterm today, so let me give it a try.. LAYER 7 - APPLICATION - Your data manipulation applications :) LAYER 6 - PRESENTATION - compression, encryption, char translation LAYER 5 - SESSION - your connection manager interface (i.e. BSD sockets) LAYER 4 - TRANSPORT- data segmentation, with checksums LAYER 3 - NETWORK - Addressing (i.e. routing, routers.. or i like "rooters") LAYER 2 - DATALINK - Bit-oriented encapsulation frames LAYER 1 - PHYSICAL - .,';,.ELECTRICAL SIGNALS.,';,. Segments are LAYER 4. Packets are LAYER 3. Frames are, duh, LAYER 2. Segments : also called PDUs, Protocol Data Units, a grouping of data gtom layers 7,6, & 5 and provides reliability and error correction for transfer. --chris 9/27/02 3:49:32 PM, "Bill Cunningham" <billcu@CITYNET.NET> wrote: >Vint, > Some of us at IETF are thinking about a draft to clear up some >terminology about the different layers of TCP/IP. >Whether it be packet, datagram, segement (more clearly defined) or whatever >the case. Do you have any opinions on this? > >