OSI Model question...

[Deanna P. Denk]

Here it is ... straight from the book BUSINESS DATA COMMUNICATIONS, 3rd
edition by David A. Stamper, Benjamin/Cummings Publishing Company, Inc.,
1991. (It's a text book I keep at my desk. I knew some of this for a
test once, but have long forgotten it. Thanks for causing me to read
some of this book again.) Hope this is helpful.

The network layer is responsible for end-to-end routing.
It performs three major functions: routing, network control, and
congestion control. The network layer must be aware of alternate paths
in the network and choose the best one. Which path depends on a variety
of factors, some of which are congestion, number of intervening nodes,
speed of links and so onl.

The transport layer is involved in end-to-end transmission services and
assists the session layer in establishing the connection for a session.
The transport layer may accept messages of any length; however, the
communications link may have limitations regarding message size. The
transport layer must segment these large messages into smaller
transmissions blocks and establish sequence numbers for each. The
transport layer is responsible for end-to-end sequence number control
and error detection and recovery. For example, if a segment of a long
message is lost, the transport layer effects recovery to ensure correct,
complet message transfer.

Another service that may be provided by the transport layer is
addressing. 

-- 
Deanna P. Denk
Internet Trainer/Consultant
denkd at interaccess.com
http://homepage.interaccess.com/~denkd/deanna.html

"I'm not unemployed, I'm a consultant"  -- Dogbert


jkaminski at BROOK.EDU wrote:
> 
>  Now something different:
> 
> sorry for change of subject, but can someone explain (simply, w/ examples)
> the difference between the Transport Layer and the Network Layer in the
> 7 layer OSI model??
> 
> Thanks in advance!!
> 
> ********************
> John C. Kaminski
> Serials/WWW
> www.brook.edu/lib/lib_hp.htm
> The Brookings Institution