Unformatted text preview: rpret meaning of data, e.g., encryption, compression, machinespeciﬁc conventions session: synchronization, session: synchronization, checkpointing, recovery of data exchange Internet stack “missing” these layers! Internet these services, if needed, must be these if must implemented in application needed? needed? application presentation session transport network link physical Why seven layers?
Need a top and a bottom -- 2 Need Need to hide physical link, so need datalink -- 3 Need Need both end-to-end and hop-by-hop actions; so need at least Need the network and transport layers -- 5 Session and presentation layers are not so important, and are Session often ignored So, we need at least 5, and 7 seems to be excessive So, Note that we can place functions in different layers Note Summary for Protocol Layering
We have broken a complex problem into smaller, simpler pieces We Provides the application with sophisticated services Provides sophisticated services Each layer provides a clean abstraction to the layer above Each...
View Full Document
This note was uploaded on 12/08/2010 for the course IEG IEG3310 taught by Professor Wingc.lau during the Spring '10 term at CUHK.
- Spring '10