Quick Quiz for all you Network+ Gurus 8)

[plucky duck]

Actually I want you to explain or describe to me the following:

OSI Model
TCP/IP
UDP
ARP
ICMP
NCP
IPX/SPX
SAP
DHCP
Netbeui

TCP/IP addresses and how they work and how the addresses come about to being what they are.

The various network services

This is sorta a refresh for you guys and a review for me as I have an upcoming test on it http://sysopt.earthweb.com/forum/smile.gif

Anyone up for a shot at it?
Or u too chicken? http://sysopt.earthweb.com/forum/wink.gif bo-bok! bo-bok! hehe.

Plucky

[Mntsnow]

http://msic.com/technical/network_protocol/osi_info.shtml
http://webopedia.internet.com/TERM/T/TCP_IP.html

http://www.transarc.ibm.com/Support/dce/general/tcp_and_udp.html

http://webopedia.internet.com/TERM/A/ARP.html

http://www.freesoft.org/CIE/Topics/81.htm

http://www.helmig.com/j_helmig/ipxspx.htm or http://webopedia.internet.com/TERM/I/IPX.html
http://webopedia.internet.com/TERM/S/SAP.html
http://webopedia.internet.com/TERM/D/DHCP.html
http://webopedia.internet.com/TERM/N/Netbeui.html

Of course the list goes on and on...I was just not about to do your homework for you http://sysopt.earthweb.com/forum/biggrin.gif

[socalgal]

Hi Plucky

I'm studying TCP/IP, so I'll start.

This is ripped, btw, from "Teach Yourself TCP/IP in 14 Days Second Edition"


OSI

Of course, some crossover of functionality is to be expected, and several different approaches to the same division of layers for a network protocol were proposed. One that became adopted as a standard is the Open Systems Interconnection Reference Model (which is discussed in more detail in the next section). The OSI Reference Model (OSI-RM) uses seven layers, as shown in Figure 1.7. The TCP/IP architecture is similar but involves only five layers, because it combines some of the OSI functionality in two layers into one. For now, though, consider the seven-layer OSI model.


Figure 1.7. The OSI Reference Model showing all seven layers.


The application, presentation, and session layers are all application-oriented in that they are responsible for presenting the application interface to the user. All three are independent of the layers below them and are totally oblivious to the means by which data gets to the application. These three layers are called the upper layers.


The lower four layers deal with the transmission of data, covering the packaging, routing, verification, and transmission of each data group. The lower layers don't worry about the type of data they receive or send to the application, but deal simply with the task of sending it. They don't differentiate between the different applications in any way.


The following sections explain each layer to help you understand the architecture of the OSI-RM (and later contrast it with the architecture of TCP/IP).

The Application Layer


The application layer is the end-user interface to the OSI system. It is where the applications, such as electronic mail, USENET news readers, or database display modules, reside. The application layer's task is to display received information and send the user's new data to the lower layers.


In distributed applications, such as client/server systems, the application layer is where the client application resides. It communicates through the lower layers to the server.

The Presentation Layer


The presentation layer's task is to isolate the lower layers from the application's data format. It converts the data from the application into a common format, often called the canonical representation. The presentation layer processes machine-dependent data from the application layer into a machine-independent format for the lower layers.


The presentation layer is where file formats and even character formats (ASCII and EBCDIC, for example) are lost. The conversion from the application data format takes place through a "common network programming language" (as it is called in the OSI Reference Model documents) that has a structured format.


The presentation layer does the reverse for incoming data. It is converted from the common format into application-specific formats, based on the type of application the machine has instructions for. If the data comes in without reformatting instructions, the information might not be assembled in the correct manner for the user's application.

The Session Layer


The session layer organizes and synchronizes the exchange of data between application processes. It works with the application layer to provide simple data sets called synchronization points that let an application know how the transmission and reception of data are progressing. In simplified terms, the session layer can be thought of as a timing and flow control layer.


The session layer is involved in coordinating communications between different applications, letting each know the status of the other. An error in one application (whether on the same machine or across the country) is handled by the session layer to let the receiving application know that the error has occurred. The session layer can resynchronize applications that are currently connected to each other. This can be necessary when communications are temporarily interrupted, or when an error has occurred that results in loss of data.

The Transport Layer


The transport layer, as its name suggests, is designed to provide the "transparent transfer of data from a source end open system to a destination end open system," according to the OSI Reference Model. The transport layer establishes, maintains, and terminates communications between two machines.


The transport layer is responsible for ensuring that data sent matches the data received. This verification role is important in ensuring that data is correctly sent, with a resend if an error was detected. The transport layer manages the sending of data, determining its order and its priority.

The Network Layer


The network layer provides the physical routing of the data, determining the path between the machines. The network layer handles all these routing issues, relieving the higher layers from this issue.


The network layer examines the network topology to determine the best route to send a message, as well as figuring out relay systems. It is the only network layer that sends a message from source to target machine, managing other chunks of data that pass through the system on their way to another machine.

The Data Link Layer


The data link layer, according to the OSI reference paper, "provides for the control of the physical layer, and detects and possibly corrects errors that can occur." In practicality, the data link layer is responsible for correcting transmission errors induced during transmission (as opposed to errors in the application data itself, which are handled in the transport layer).


The data link layer is usually concerned with signal interference on the physical transmission media, whether through copper wire, fiber optic cable, or microwave. Interference is common, resulting from many sources, including cosmic rays and stray magnetic interference from other sources.

The Physical Layer


The physical layer is the lowest layer of the OSI model and deals with the "mechanical, electrical, functional, and procedural means" required for transmission of data, according to the OSI definition. This is really the wiring or other transmission form.


When the OSI model was being developed, a lot of concern dealt with the lower two layers, because they are, in most cases, inseparable. The real world treats the data link layer and the physical layer as one combined layer, but the formal OSI definition stipulates different purposes for each. (TCP/IP includes the data link and physical layers as one layer, recognizing that the division is more academic than practical.)

Terminology and Notations


Both OSI and TCP/IP are rooted in formal descriptions, presented as a series of complex documents that define all aspects of the protocols. To define OSI and TCP/IP, several new terms were developed and introduced into use; some (mostly OSI terms) are rather unusual. You might find the term OSI-speak used to refer to some of these rather grotesque definitions, much as legalese refers to legal terms.


To better understand the details of TCP/IP, it is necessary to deal with these terms now. You won't see all these terms in this book, but you might encounter them when reading manuals or online documentation. Therefore, all the major terms are covered here.

Here's a link for either the same or similar book on amazon.com. Mine comes from another source. Teach Yourself... (http://www.amazon.com/exec/obidos/tg/stores/detail/-/books/0672311674/similarities/ref=pm_dp_ln_b_10/103-4848257-3967817#same_store)

Good luck http://sysopt.earthweb.com/forum/wink.gif


[This message has been edited by socalgal (edited 10-11-2000).]

[plucky duck]

Mntsnow - doh!

Socalgal - u cheater http://sysopt.earthweb.com/forum/smile.gif *copy and paste*

[socalgal]

Did you think I was going to type all that for you? Watch out, I might pop quiz ya http://sysopt.earthweb.com/forum/wink.gif

[plucky duck]

I'm back from the test http://sysopt.earthweb.com/forum/smile.gif

I did one of those class test, not the REAL Network+ Test. Not ready for that yet, unh-uh. http://sysopt.earthweb.com/forum/smile.gif

I got stuck on a question and just kinda guess. Can someone tell me if what I did was right? OK, I kinda forgot the question, so I'll just give it to you guys in relative terms:

You are a network admin. Given an IP address of 198.68.0.0. you are asked to set up 254 networks. How many hosts can you have max per network?

My answer(guess):
My guess for the max # of hosts was 254. Answer derived from taking 2 to the power of 8 minus 2. So 256 - 2 = 254?

Is that right or no?
See I told ya I'm a as dumb as a duck http://sysopt.earthweb.com/forum/wink.gif

LMK thanks,
Plucky

[This message has been edited by plucky duck (edited 10-14-2000).]

[Erap!]

maybe he was testing if any of you guys were actually gonna spend time answering those?? hehehhehe

[cyclone2]

Well gee, maybe you're as smart as a swan! http://sysopt.earthweb.com/forum/smile.gif
If you subnet 198.68.0.0 with 255.255.255.0 you would get 198.68.1.0 to 198.68.254.0 =254 networks
They would then have 198.68.1.1 - 198.68.1.254 [=254 hosts on each] all the way to 198.68.254.1 - 198.68.254.254
Sound right?

[plucky duck]

Yuppers http://sysopt.earthweb.com/forum/smile.gif I just took a guess on that one and wowee! I actually got it right, hehe http://sysopt.earthweb.com/forum/biggrin.gif

I didn't score too bad. 43 out of 47:P

Now lets start on the next chapter about the physical transmission medias http://sysopt.earthweb.com/forum/wink.gif You know...all that cabling stuff http://sysopt.earthweb.com/forum/frown.gif It would be much easier for us if we actually a practical physical element into this course per say actually seeing and touching of the network hardware http://sysopt.earthweb.com/forum/smile.gif Us guys like me are hardware freaks! http://sysopt.earthweb.com/forum/smile.gif AHHH!!!

Coaxial cabling
Cat 1-6 cabling
Fiber Optic cabling
Blah Blah Blah

Hehe, and then there's the *vampire tap* http://sysopt.earthweb.com/forum/wink.gif Now what do networks admins do with them? Tap unauthorized users in the back? LOL http://sysopt.earthweb.com/forum/smile.gif

Plucky


Plucky

[Ted61]

What to you mean "blah, blah, blah"? The cabling stuff is the best. Coax is for some home users but cat 5, 5e and 6 are fun. The fiber optic stuff is great there is nothing like getting some 50um single mode working on a teleconference network.

It is a lot better now that all of the equipment is cheap enough to play with.

[plucky duck]

blah = etc http://sysopt.earthweb.com/forum/wink.gif

Can someone give me an idea as to how much each type of cable would cost say per 10 feet?

And when one sets up the physical network with all the wiring of cable and stuff, how do you manage to get by with all those walls and other already embedded wiring? I take it that this requires major planning and informed decisions eh? Prolly the layout of the building is this first thing thats needed. Just curious. Don't mind me if I sound like an idiot who doesn't know what in the world he's talking about http://sysopt.earthweb.com/forum/wink.gif hehe

Plucky