"Howard C. Berkowitz" wrote:
>
> The topic that will never die... :-)
Right because I am getting more and more confused by the thread I
(inadvertently) started ;-( The more I wanted to get away from OSI
reference model, the closer we got.
I thought we could do without (anyway TCP/IP is older than the '84
endorsed OSI model standard) and could concentrate on TCP/IP layering
concepts. Not that I do not like OSI, the contrary. On one side this
shows the usefulness of (and reason why we all need to learn and
understand properly) OSI RM.
So now I am confused on both fronts:
"Howard C. Berkowitz" wrote:
>
> Again, we are getting into a situation where there is a desire to
> coerce things into a simplified version of the OSI model. Real OSI
> documents are very careful about the protocol versus service
> definition, and indeed you will find separate documents, say, for the
> transport service and the (several) transport services. Doing things
> this way completely sidesteps the "what layer is this" problem.
>
I always thought the the layer is defined by its service(s) provided to
its upper layer. These services are reflected in the functions needed to
be performed within the layer. And protocols residing (operating) at the
layer should "fulfill" the function(s).
Overall, where the number of protocols operate at a certain layer, they
altogether should cover all the functions at the layer (with some
potential "redundancy" - where alternative protocols exist, well, not
quite, the alternative protocols actually seem to perform subset or
superset of layer functions - like UDP or TCP, or TP0-TP4 of OSI
architecture).
What is wrong in my understanding (and need to see the structure) which
somehow tortures me to fit ARP a protocol in a particular layer of the
protocol architecture it was developed for?
Rita
P.S. Sorry for those feeling this discussion redundant. My horoscope for
today says it all:
"You may not be the star performer at the moment, but there's great
delight in playing second fiddle. Without your part, the arrangement
would sound empty. Small contributions yield big rewards. " ?-)
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=8695&t=8335
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