Techie Blog

hello afreen, I'd like to correct you. your introduction reads that C is the basic of all languages. this might be wrong. in my point of view Assembler is the basic language on which other languages are based on. Or am I wrong?
You should explain the TCP/IP layer model, because this is as important as the OSI layer model. the difference between these models are that the OSI layer model is an artifical model and the tcp/ip layer model is the older model which has been improved over time and came with the first steps of network development in the 1970. the tcp/ip layer model is directly related to the origins of networking. the osi layer model was a later development for easier explanation and ways to find errors on networks. in addition to your blog I'd like to say what you can finde on each osi layer.
1.) physical layer - cable, network cards, repeater, ...
2.) data link layer - hubs, switches
3.) network layer - router, ip
4.) transport layer - tcp/udp
5. - 7.) ... - https, ftp, dns, smtp, nis, snmp, tftp, ... data and application stuff

Yep true that's the base,but the programming concept or I should put it this way,that just cause of C,its C who paved the way for other programming concepts,people who's familiar with C can know what programming is all about,well they're cases wherein people just learn java directly(that's due to the concept of classes introduced there(classes concepts are even in C++)).

TCP/IP is no different,but just has 4 layers ie:
4)Application Layer(Application+Presentation+Session(of OSI)).
3)Transport
2)Internet
1)Network Access(Physical & data link layer)

Thanks for you're insight though..

Sorry, this is going to be long, as usual

Blog has been open for everybody so far and that has been working mostly just fine. Occassionally something has to be removed if it's against the guidelines, if we get stuff like this, it's better to keep it open by all means.

I find TCP/IP layers easier to remember for some reason. Memorizing just those layers goes long way in understanding networking. I don't understand why people always start with OSI model, unless it's way to make TCP/IP model seem even simpler

Practical example when knowing which device belongs to which layer is useful, is when to use straight or crossover network cables. Crossover when connecting devices operating on same layer, straight cable when going from layer to another. For example crossover between switches (layer 2) and straight cable when going from switch to router (layer 2 to layer 3). Most switches don't mind though anymore, but it's still good idea to use crossover cables when connecting two computers without having swhitch in between.

One more thing to remember about layers is that layers interact just with one layer below or above, depending on which way packet is travelling. Application layer doesn't have to worry about what's going on in Internet or Link Layer.

Programming language part is slightly misleading indeed. C and languages influenced by it are most popular compiled languages and everything else is in the minority (there's more variety in scripting languages). That doesn't mean that it's base for all languages, though it's true that it was base for the C++, which in turn was base for Java and C# to name just few. Layer princible works nicely with those languages, knowing one will help learning language in layer below or above.

Though still, C was not the first programming language by far as you have to have A and B first

I guess B was BCPL and A might have been Algol.

Fine...

Yeah people always start with OSI in order to give the reference to tcp/ip,its like knowing the concept of classes through C++ to know java.or sometimes...vice versa also works.

Well,now that you've mentioned so...we've got 2 types of cablings
Straight and Cross cabling.
Just to know where the cables are used,the basic difference is Cross cables are used for Same devices(switch-switch,pc-pc,router to pc...),where as straight cables are used for Different device(switch-router,switch-pc....).

For router-router we use a serial cable.
And yeah,application layer is just the user interface layer.

Of course everyone knows about many langauges that come up before C,but the basis for typical Object oriented programming started with C++(enhanced version of C).So on that basis i told,C to be the basis of languages.Hope am clear now..

Originally posted by afreen rahman:

Well,now that you've mentioned so...we've got 2 types of cablings
Straight and Cross cabling.
Just to know where the cables are used,the basic difference is Cross cables are used for Same devices(switch-switch,pc-pc,router to pc...),where as straight cables are used for Different device(switch-router,switch-pc....).

When referencing to layers 2 and 3, I was referencing to OSI model. Higher layers don't seem to matter that much with choosing cables.

The thing with choosing RJ-45 cables is that devices expect crossover type of connection and network switches and hubs (in other words layer 2 devices as they that's the highest layer they care about) switch the wiring around. When connecting two computers together that isn't done and both ends expect to receive signal from wrong wires.

It's easier to wire things if you can expect incoming signal to come from one wire and that you can use other to send. For that to work, wire that's used to send on one end, has to be used for incoming signal on the other end. That way both ends can easily send and receive data at same time without getting collisions.

Modern switches are usually smart enough to detect wrong wiring and correct things on the fly.

Originally posted by afreen rahman:

For router-router we use a serial cable.
And yeah,application layer is just the user interface layer.

I haven't seen that many stand alone routers(expect small ADSL routers), but I would guess that serial cable is used for managing the router, not for connecting routers together.

Most of the routers that I have seen have been part of a switch either as module or already part of the switch software. Those seem to work as layer 2 devices from the cabling point of view.

Originally posted by afreen rahman:

Of course everyone knows about many langauges that come up before C,but the basis for typical Object oriented programming started with C++(enhanced version of C).So on that basis i told,C to be the basis of languages.Hope am clear now..

Not quite. C++ wasn't the first objected oriented language and it's derivatives are not only modern object oriented languages out there right now. Key here is that C and C++ are just popular languages, not really first of doing anything as far as I know. Popularity is limited also to compiled languages, there's quite lot of popular interpreted languages out there that have nothing to do with C.

I wouldn't concertrate that much trying to explain networking with programming language terms as reader has to then understand both programming languages and networking. And as bonus, you have to be careful with explaining both parts correctly.

Well,let me write about 'collision domain'..because as am learning things from you and also institute where am presently doing a course in networking ..Hub is considered as Collision domain,all ports of hubs are in collision domain,network congestion occurs at a higher rate. From switches point of view,every port has a collision domain,but has this lower network congestion.

Most of the routers that I have seen have been part of a switch either as module or already part of the switch software. Those seem to work as layer 2 devices from the cabling point of view.

well,i didn't understand this part...i mean when doing practically on packet tracer..to connect 2 routers we use a serial cable..but not all routers are connected,i've seen just generic routers being connected using a serial cable..i've tried connecting the other routers using DCE but it doesn't work. well,i've been taught to know C as the basis for learning other object oriented concepts,thats because of easy learning to other programming OO languages,they're people who just start off with java without knowing C,so..still C has been the base..LOL,if you want i'll just take off that line saying "C to be the basis of programming language".,I see you're a test engineer yourself,and a senior to me..so you'd be knowing things much better.Am just a student,learning but didn't have any practical work experience in software field..

there's quite lot of popular interpreted languages out there that have nothing to do with C.

C is one among the popular and as well as interpreted language,. yeah,its getting jumbled up here...networking with programming,but my sir who's a java expert is dealing with networking,says when u have programming knowledge,then its easy for you to understand certain things..dunno on what basis he told. yeah i know..am getting sloppy here..so you're correcting it,so not a problem..

Originally posted by afreen rahman:

well,i've been taught to know C as the basis for learning other object oriented concepts,thats because of easy learning to other programming OO languages,they're people who just start off with java without knowing C,so..still C has been the base..LOL,if you want i'll just take off that line saying "C to be the basis of programming language".

That particular sentence just gives people reason to start correcting you on programming side of things, I don't think it helps that much in understanding the actual matter.

Originally posted by afreen rahman:

C is one among the popular and as well as interpreted language,.

I hope you didn't mean that C is interpreted language. That term is used for languages that are translated to machine code when they are run. C is compiled language, which is compiled into machine code and compiled binary is distributed instead of the source code. You don't need to have the compiler to run the binary. In case of interpreted languages you need to have the interpreter to run the program. Examples of interpreted languages are Perl, Python and Ruby.

While compiling while you run the code slows things down, interpreted languages have their place though. Programming something in for example Python is extremely fast, they actually have competition for programming game in one day (http://pyday.pynguins.com/).

Those interpreted languages are quite easy to learn, but I guess C is often chosen as teaching language as it's basically C++ without complexity of object oriented programming. As a bonus, structure is quite easy to learn. Pascal has even cleaner syntax, but it's not that popular anymore.

C++ is step for advancing Java, as Java was designed to be easy to adapt for C++ programmers.

That particular sentence just gives people reason to start correcting you on programming side of things, I don't think it helps that much in understanding the actual matter

Yeah let them correct,its not like i made a mistake in syntax or something...like i said..We've been taught C to be the (dash )language..and actually never known or tried to learn other interpreted languages like python..or perl or whatever,and yeah like you said..C is often chosen as teaching language.I also know that these interpreted languages are quite easy to learn. Edited now..Check in..

lol...yeah java is yet another programming language..and its okay..,i don't know about python..
%s->printing a string or something....

ah okay....thanks....its like an assignment operator....once u have knowledge about any language its easy to learn different languages..,but here we're not defining 'S' at the beginning but just directly i guess right?
%s=%S.

hmm ok,same like that of C and other stuff..%S-->denotes the assignment of string type...

wow... haha^^ hi Alex and Afreen. So both of you are members here.

can i ask some techie questions?

hi,yea if u want to...

how do i upgrade the virtual memory, REM, disk space of my laptop? sorry, i've been using it but i don't know much... i use it mainly for typing. hehe^^ and i downloaded so many applications that it crashes down... it always say... need more space for virtual memory. what does that mean anyway?

You can use the forums too. There you can make your own separate topic, so interested people can find your question easier. Now somebody might skip this thinking that we're still going on about networking.

Virtual memory is combination of physical memory and additional memory called swap. Swap resides in disk and is slow to access, but makes total memory seem larger. You can enlarge the swapfile, though things might get quite slow.

Best way is to add more physical memory if possible, or just make sure that there are no extra programs running. Some programs can be sneaky and start up without asking when you boot the computer up. I can search for some instructions at least for enlarging your swap if you tell me what operating system you are using. And please consider making new topic in the forums.

hi Anzah! thanks for the reply. before i post a topic in the forum, must i be a member? i would love to know how to add more memory... and yes it is more appropriate if more could read about my query. thanks again.

Oh, you're right. You have to be member to post new topics. Preferences don't even have any settings for non members. Commenting and reading is allowed for almost all areas. Getting membership is quite straightforward though.

ah ok,been busy these days..so..well upgrading virtual memory...hmm...you've already got the answer i suppose just close some of the programs and its almost set to free,it also depends on which operating system you're using..XP..has its own way of freeing things and other OS's too...if you don't find your answer here then just google around..its much easier.

Anonymous writes: hey are guys professionals..????

well,studied something professional,would like to be trained in that field....Anzah here is a trained and working professional so yeah..he's the one..

hey,am good thankyou