OSI Model

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I am currently reading the Groth Network+ book and I have got up to the OSI model and it says that the Network+ exam does not cover the upper layers (Session, presentation and application), I am surprised at this can anyone confirm if this is correct?

 

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It does and it doesn't, most network engineers don't really get into the upper levels, its more OS and Application stuff for software developers. The exam does cover these layers because it covers basic application protocols and their use HTTP, FTP, SNMP etc. Most real world solutions rely on several protocols, applications and pieces of hardware to do something useful that generally maps to all the layers of the model. The N+ covers alot of tunneling and security protocols some of which probably map partly to the session layer.

So the upper levels are barely covered but thats because they don't really mean much to the average Network engineer who typically starts at the botton with the physical devices. Sys admins care about the application layer but only really in an expert user sense normally. Typically only hackers and software developers are gonna care much about the details of these layers. Basic application protocol knowledge is probably useful for setting up firewalls to pass the traffic.

 

Well...doesn't cover them *in detail*. You are still responsible for knowing the basic information such as where these layers occur in the model, what protocols are associated with each layer, and so on.

 

I'd say the Security+ does that more, the Network+ does not tell you the details of how applications communicate, what they put in their headers, when they open connections, how the session is established and torn down etc. Just knowing HTTP is used for browsers and sits in the application layer typically listens on TCP port 80 really tells you very little. It does not allow you to appreciate Webservices,SOAP,REST,the various payloads, mime types, how the browser works, how the web server works etc.

The application layer is by definition defined and created by application developers, just some of these apps become standards. As such its constantly changing. The payloads change all the time. Also new app protocols are created like Bittorrent or the Windows Live Messenger protocol etc.

 

2005 Network+ Objectives
Domain 2.2: Identify the seven layers of the OSI (Open Systems Interconnect) model and their functions.

Domain 2.12 covers the protocols mentioned by dmarsh and several others are mentioned elsewhere. If it's in the objectives, it may well be on the exam. And chances are you'll need it elsewhere in your career. I'd suggest you get familiar with them.

 

From the bottom up:
Physical - Data Link - Network - Transport - Session - Presentation - Application

Please - Do - Not - Try - Shagging - Paula - Abdul

Well it worked for me!

 

That has to be the best way to remember that for my uni exams in may!!! Reps to you!!!

 

LOL - certainly better than the old 'All People Seem To Need Data Processing' or 'Please Do Not Throw Sausage Pizza Away' mnemonics I was taught!

 

ha LOL I used to want to do that when I was a teenager.

Seems like a good way to remember

 

Nice one, i just stick to the plain old:

All
People
Seem
To
Need
Data
Processing

 

Some
People
Fight
Back

sessions or segments (lol cant remember)
Packets
Frames
Bits

 

The other one i know is this one from the top down:
All-Polar bears-Swim-To-Near-Deep-Pools

 

Well, you certainly found some interesting ways to remember the names of the layers and their order. Somehow, I think you're going to get into them a lot deeper than that. I'd suggest you heed the words of Dmarsh and Trip in their original posts and reread the objectives. Good Luck.

 

Back to my sixth form and A-Level days:

All
People
Seem
To
Need
Data
Processing

 

I remembered this using:

Sid
Plays
Football
Badly

Dunno... it worked for me... lol