Networking terms

[Ngoh Chean Siung]

Hi,

Q1) What is collisions?
Q2) What is Bandwith?
Q3) What is the different between hubs and switches? Because as I know, by using switches, it will overcome the collisions and bandwidth problem. But, how?
Q4) What is NIC (Network Interface Controller)? Is it means network card?

regards.

[Dexter Filmore]

This should answer your questions:

http://bugclub.org/beginners/networking/

[Deoncia Grayson_1]

Collision occurs when two stations transmit at the same time on the wire.

Bandwith The amount of data that can be transmitted via a given communications channel (e.g., between a hard drive and the host PC) in a given unit of time.

Differences between hubs and switches
They both do the same but hubs sends packets of data through all of its parts and therefore may cause collisions/ switches sends packets through different partsâ ¦

Check out the link below:

http://www.duxcw.com/faq/network/hubsw.htm

NIC (Network Interface Card), which plugs into a computer and adapts the network interface to the appropriate standard. ISA, PCI, and PCMCIA cards are all examples of NIC

[Steven E. Protter]

Q1) What is collisions?
Two packets prevent each other from getting through the network. Usually happens when there is heavy traffic. They have to be re-transmitted.
Q2) What is Bandwith?
Size of data pipe. The limit of how much data you can get through during a given period of time.

Q3) What is the different between hubs and switches?

Switches are configurable, they are generally faster and some have smart features built in and actually have modifyable operating systems. Hubs have none of these features.

Q4) What is NIC (Network Interface Controller)? Is it means network card?

Yes
Network Interface Card.

SEP

[Ranjith_5]

Hi Siung,


1.) Network Collision
-----------------------------

Ethernet is a shared media, so there are rules for sending packets of data to avoid conflicts and protect data integrity. Nodes determine when the network is available for sending packets. It is possible that two nodes at different locations attempt to send data at the same time. When both PCs are transferring a packet to the network at the same time, a collision will result.

Minimizing collisions is a crucial element in the design and operation of networks. Increased collisions are often the result of too many users on the network, which results in a lot of contention for networked bandwidth. This can slow the performance of the networks from the user's point of view. Segmenting the network, where a network is divided into different pieces joined together logically with a bridge or switch, is one way of reducing an overcrowded network.


2.) What is bandwidth?
------------------------------

The range of frequencies, expressed in Kilobits per second, that can pass over a given data transmission channel within a frame relay network. The bandwidth determines the rate at which information can be sent through a channel - the greater the bandwidth, the more information that can be sent in a given amount of time. Usually measured in bits-per-second. A full page of English text is about 16,000 bits. A 56Kbs modem can easily move 16,000 bits in less than one second


3.) Difference between Hubs and Switches:-
--------------------------------------------------

See the following Link.

http://www.duxcw.com/faq/network/hubsw.htm

4.) NIC=Network Interface Card = LAN Card


Regards,
Syam

[Ngoh Chean Siung]

Hi,

What you mean is before data was sent out, a packet will be sent out first as the signal to send out the data, right. By the way, how's the packet looks like and in what format? Binary form or ...?

For hubs, the data will be broadcasting to all the other ports. But, why only the requested can get the info whereas other users cannot? Is it because the MAC address?

regards.

[Bharat Katkar]

HI,

To start with HUB and Switches:

Now let us assume you have 16 port HUB and a 16 port switch.

Now you connect 16 computers to the ports of HUB. You have to install Network Card (it is like other addon cards in the system) and configure it's drivers and protocol (TCP/IP) on each system. Then you have a PATCH Cord (Network Cable) which connects to HUB and it's a RJ45 connector cable. SO it looks like a Start Network. Each network card has MAC address which is burnt on the card and is unique.
Now suppose Comp1 wants to send data to Comp13 then it clubs MAC address of Comp13 and data (called as frame/packet) to be sent together and sends it to the HUB. HUB then gets the packet received on Port 1 and broadcast this packet to all ports of the HUB. Now from Comp2 to Comp16 everybody will recevie that packet and all except Comp13 will discard the packet looking at the MAC address. COmp13 will realise that this packet is sent for him looking at that MAC address and receive the same.
On the contrary if you are using switch (which is more intellegent than HUB) maintains a small table in memory (NVram). This table has mapping of ports to MAC address i.e. switch know which MAC address is on which port. So in Switch packet is received from comp1 by and sent directly to port 13 where Comp13 is connected. So switch will not broadcast the information but will send it directly to recipient. Effectively in switch you can have multiple such communication happening at a time and thereby reducing collision.
In HUB only a single pair can take part in communication whereas in switches you can have multiple pairs communicating with each others.
So this how it make difference.

Now in case of HUB if Comp1 is sending packet to Comp13 and by the time Comp10 also send packets to Comp11 then these two packets if came at the same time to HUB get collided and none of them is transmitted. IN this case both Comp1 and Comp10 will keep on trying by resending the same packet till they don't reach at same time.

Now bandwidth is the capacity of the media i.e. (many times it is ethernet) cable (PATCH CORD) to carry the data in certain period of time. You can compare this with Road traffic. Suppose have a 3 lane road then at a time three cars can go but if you have 6 lane road then 6 cars can go at a time. SO the later one has higher Bandwidth.
As an example bandwidth is given as 100Gb/s that mean it is capable of sending 100 Gigabits (107374182400 bits) of data per second.

NIC is already explained.

Suggest you to go thr' OSI layers concept and get to know about different protocol suites used in comminucation e.g. TCP/IP.

Hope that helps.
Regards,