September 12th, 2004 04:52 AM
Hey all !
This is my first Tutorial ... well..actually my second attempt to write one .The first one didn't
turn out to be a tutorial and i had to move it to the General Discussions Forum .I
guess it will help newbies to get a basic understanding of the various networking devices...
[gloworange]Network Interface Card [/gloworange]
This is a device with many names like LAN adapter,Network Interface Unit,Network Card.It is
commonly referred to as NIC. An NIC helps a computer to communicate with the Network with
the help of drivers and the computer's OS. So if u want to create a network of pcs, you
should purchase NICs for every pc connected .They usually fit into the expansion slots.
Sometimes they come Onboard with the motherboard.It is also important to note that NICs
differ with the network architecture they support.
When the physical distance of a network topology has to be increased, a device called
repeater operating at the physical layer is used.A repeater takes the input signal and
regenerates it by amplifying it.In thisway it overcomes the distance limitation.When a signal is
regenerated,there is also a possibility of "noise" being regenerated.It also increases the
latency thereby increasing the chances for timeouts.
Hubs are multiport repeaters operating at the physical layer.It amplifies the input signal and
sends it to all the nodes connected to the hub without looking at the data.It has therfore only
a single collision domain.Hubs create a physical star network where the hub is the device is
central device.But unlike a star network the hub does not forward data only to the destination
node but sends it to all the nodes.
Bridges are used to breakup collision domains,combine two different networks or to
regenerate the input signal(like a repeater).They operate at the Data Link Layer of the OSI
layer.They can also be used to filter out specific types os traffic like ARP,SAP etc.Bridges are
software based and therefore increase the latency to a great extend( i guess about 30%).
Therefore there is a good chance for TIMEOUTS.So its better to use combinations of hubs and
switches to break up collision domains.
They devices operate at the Network layer of the OSI model.They are used to breakup
broadcast domains,control multicast traffic,connect between different topologies.Their
decisions are based on logical addressing rather then physical.
Similar to bridges they break up collision domains.Because of the fact that the decisions are
hardware based they reduce the latency.They are in effect like multiport bridges.The
forwarding decisions are based on the physical address.By using ASICS (Application specified
integrated circuits) higher speeds can be achieved.
Firewalls are software based,hardware based or a combination of both .A hardware firewall
is made up of a router or access servers.There are several types of firewall techniques:
Packet filter->It checks every packet that comes in.
Application gateway-> application specific security mechanisms
Proxy server->This hides the true network address.All the transmitted data is intercepted
Throughout this tutorial i have talked about different devices operating at certain layers.
Networking is very complex and inorder to make it simpler, each networking operation
is divided into different layers.The ISO OSI has divided these tasks into seven layers.
Application Layer : Interface between user and the network eg.Browser,Ftp client
Presentation Layer : Presents data and does operations like encryption
Session Layer : Keeps different applications data separate
Transport Layer: Error correction as well as reliable or unreliable delivery
Network Layer: Routing and logical addressing
Data Layer: Converts packets to bits and bits to frames,error detection(no correction)
Physical Layer: Moves bits over the transmission medium,specifies voltage etc.
Each device operating at a specified layer performs its own specified tasks
[pong]Happy Networking ![/pong]
September 12th, 2004 05:18 AM
Is english not your first language? Or are you just not trying on grammar? The info is "ok", and could be greatly improved, but your grammar sucks. If english isn't your first language you should still know "you" instead of "u". You also need spaces between your periods and the begining of the next sentences. Your tutorial looks like crapola from a grammar standpoint... That is certainly the biggest problem... Following that with a close second is the lack of information... All you did (it looks like at any rate) is go to webopedia or the likes and copy the definition of each of those words... VERY lacking definitions, go into a little more detail, throw a light review of the layers so people who don't know about them can figure out what you are talking about.
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September 12th, 2004 05:38 AM
True grunt... english is not my first language and also not my second.I wasn't writting a novel here and i think the grammar is good enough for a technical tutorial.Anyway i'll add more info on the layer part ...
September 12th, 2004 07:03 AM
Sorry folks if this tutorial was not too deep. Told you this is my first tutorial.Anyways i learned this lesson
When you write a tutorial , make it really deep and always read it over again to correct
the grammatical errors because grammar does make a difference !
Until Next time
September 12th, 2004 09:40 AM
imthink its fine other readers. The important thing here is that
he tried to write a tutorials so others would have a view of what a
September 12th, 2004 10:07 AM
No. I think the important thing is for him to put a good amount of effort into it. Not just throw something together and call it a tutorial.
When death sleeps it dreams of you...
September 12th, 2004 02:23 PM
For Nic's I would of went into more detail about the different types of cards and the different slots Isa/Pci and would include information about ethernet cable standards
10base2 is 1 Mbps thin coaxial cable
10base5 is 10 Mbps thick coaxial network cable
10 baseT 10 Mbps unshielded twisted pair
100 baseT 100 Mbps shielded twisted pair
100BaseF 100 Mbps fiberoptic network cable
1000BaseT 1Gbps Copper cable
1000BaseF 1Gbps fiberoptic cable
And more information about the OSI layers would be very helpful for those people who are new to networking. I would also include the definitions of the acronyms used such as ARP(address resolution protocol) SAP (Service Advertising Protocol).