What are the 7 layers of OSI model or TCP/IP

Applications UNIX Desktop Questions & Answers
1

what is it??

I looked everywhere but cant seem to find it

also where can I get information about the difference between NFS 2 or NFS 3??

2

i have a feeling that this is a homework assignment. I hope you did read the Forum Rules if this is an homework assignment.

Check this link for the OSI TCP/IP
http://www.uwsg.iu.edu/usail/network/nfs/network_layers.html
http://www.kristall.ethz.ch/IZA-SC/Atlas/data/models/OSI_mod.html

For the NFS 2 & 3
http://nfs.sourceforge.net/nfs-howto/intro.html

3
  1. Physical layer
  2. Data Link layer
  3. Network layer
  4. Transport layer
  5. Session layer
  6. Presentation layer
  7. Application layer

www.webopedia.com/quick_ref/OSI_Layers.html

4

Here's a good way to remember it:
All People Seem To Need Data Processing

Application, Presentation, Session, Transport, Network, Data-Link, Physical.

5

Here is another question:

With N-tier web application services and publish-subscribe architectures in the picture, what are the current layered protocol stack (complexity management) models?

6

First, please see my post in this thread.

Stuff like this does not modify the basic networking protocols. Rather, it imposes much more order on the application layer. The three tier model, which my company now uses, says that the user should not need a special client for your application. Instead, the user should just use a local web browser. Next, the user should not be expected to learn sql or anything like it to search a database. Some kind of easy to use middleware should interupt the user's needs and figure out what to do. That front-end to our database is complex and multi-layered itself. But we still call the whole concept a three tiered approach.

In the old days, we would have delivered special client software to our customers with its own user interface. And some skill would be needed to search our database. Now our customers just use a web browser and this alone shortens the learning curve. And you could probably teach Lassie to search our database...no sql or anything.

But the whole shebang is running on TCP/IP which has not changed. I don't know what publish-subscribe means, but I doubt that it modified TCP/IP either.

7

The OSI stack was developed for a strict client-server architecture. One new "web centric" architecture is more like"

  1. Presentation Logic
  2. Personalization Logic
  3. Session and Session Security Logic
  4. Application Logic
  5. Information Sharing Logic


    ....lower level transport stacks here ....

The old OSI client-server model does not apply to multi-tier 'web driven' architectures because presentation logic and personalization logic are at the top of the stack and application logic is moved to the middle tier.... this decouples presentation and personalization from application and publish-subscribe peer-to-peer services. OSI applies toward a specific class of client-server that predates n-tier.

Sorry, trick question :slight_smile: