Monday 11 June 2012

Computer Networks: chapter 2

Posted By Maher Bro


COMPUTER NETWORKS : CHAPTER 2 -basic communication


I hope you read first chapter , well if you already know that than no problem .
we will start chapter 2 and i will be writing about how devices communicate in a LAN and how they communicate to cloud.


BRIEF INFRA OF LAN


Ok now u are in a LAN , then you must see a cable connected to your laptop or PC or watever device is there in your network.Those cables are called Ethernet Cable , and that cable is connected to NIC (network interface card ). NIC is installed in your computer , the port to which cable is connected is a part of NIC .
The cable is then connected to a SWITCH . A switch connect all the devices within your network and then in most cases switch is connected to a ROUTER .A ROUTER connects your network to outside world, which may be INTERNET or to another network.
So this was a brief infra of your LAN.

CLOUD


i have used the term CLOUD. U must have heard this word (not sky clouds LOL).Cloud is a common word by which we refer a very large
network or a very large collection of networks, which is internet.
In cloud there are a hell lot of networks which are interconnected , which are distributed all over the globe.
You can find all the servers in cloud like FTP servers, HTTP servers, SMTP servers, DHCP servers etc.

MEMORY ESSENTIALS


I know all of you know this but just for a quick revision m going through how we memories are defined in computers:
smallest unit is a BIT.
byte=8*bit
kilobyte = 1024*byte
megabyte = 1024*kilobyte
gigabyte = 1024*megabyte
terabyte = 1024*gigabyte

IMP NOTE - Whenever you say your connection speed is some Kbps or some Mbps , means your connection speed is some kilobit per second or some megabit per second
not kilobyte or megabyte .

BANDWIDTH


a rate of data transfer, bit rate or throughput, measured in bits per second (bps)
or u can say this how wide the road is

DELAY


the delay of an IP packet within an IP network
or u can say how fast cars are moving.

So thats all for this chapter . Feel free to ask. Stay connected

P.S- the symbols for router and switch shown are standard symbol . keep them in mind

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