Internet:
The explanation
above covers the connections between computers on a local network, but what
connection methods are used for the Internet? Your Internet service provider or
the companies for which you work probably use one of the fast internet
connections, which are described in table. This following table summarizes the
most common Internet connection types and their speeds.
|
Connection
Type |
Speed |
Details |
|
DSO |
64 kilo bits per
second |
1/24 of T1 line
or one T1 channel |
|
ISDN |
128 kilo bits per
second |
2 DSO working
together to provide a high-speed data connection |
|
T1 |
1.54 megabits per
second |
24 DSO lines working as one, with 23
carrying information and one other line. This type of connection has become
common for schools and business. |
|
T3 |
43.2 megabits per
second |
672 DSO lines
working together. This method is the equivalent of T1 lines. |
|
OC3 |
155 megabits per
second |
All OC lines are
optical & do not use traditional phone lines are quite fast, very
expensive, & are often found at telecommunications companies. |
|
OC12 |
622 megabits |
The equivalent of
366 T1 lines or 8064 phone lines. |
|
OC48 |
2.5 gigabits per
second |
The equivalent of
4 OC12 lines. |
It
is common to find a T1 connection lines in many places. Sometimes you can get a
cable modem speeds comparable to a T1 line. Note the cable modems were not
listed in above mentioned table simple because their actual speeds vary greatly
depending on a variety of circumstances, including how many people in If you
are using a cable modem in the immediate area.Unless you work in
telecommunications you are not likely to encounter OC lines.
Data
Transmission
We
have briefly seen the physical connection methods, but how is data actually
transmitted? To transmit data, a packet is sent. The main purpose of a cable to
transfer packets from one machine. It does not matter whether that packet is a
part of document, video, image or just some internal signal from the computer.
This fact begs the question: What, exactly, is a packet? As we discussed
earlier, everything in a computer is ultimately stored as 1s & 0s, called
bits, which are grouped into sets of eight, called a byte. A packet, also
referred to as a diagram, is a certain number of bytes divided into a header
and a body. A 20-byte packet header section at the beginning. The header tells
you where the packet is coming from, where it is going and more. The body
contains the actual data in binary form and you want to send. Above routers and
switches his work to be read as part of a packet header. This packet should be
sent to how they determine.
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Protocols
there are different types of network communications for different purpose. The
different types of network communication are called protocols. A protocol is
basically an agreement on a communication method. In fact, this definition is
how the word "protocol" is used in standard, non-computer use. Each
protocol has a specific purpose and normally operates on a certain logical
port.
Some of the most significant protocols that are currently used include TCP, IP,
UDP & ICMP. TCP (Transmission Control Protocol) enables the host computer
to establish a connection and exchange data. This guarantees the delivery of data in proper
order. IP (Internet Protocol) specifies the format of the packets and the
addressing scheme. Most networks combine IP with the higher-level TCP to form to
protocol suite known as TCP/IP (Transmission Control Protocol / Internet
Protocol), which establishes a virtual connection between a destination and
source. Something similar to the IP emails system by itself. It allows you to
address a package & drop it in the system, but there is no direct link
between you and the recipient. The TCP / IP, on the other hand, they set up a
connection between two hosts so you can send messages back and forth for a
period of time and.
UDP (User Data gram Protocol) is a connection less protocol, meaning that it is a
network protocol in which a host can send a message without establishing a
connection with the recipient. UDP runs on top of IP net recovery services.
Instead, it offers a direct way to send and receive datagrams (packets) over an
IP network. Its primary use is broadcasting messages over a network, but it
does not guarantee the delivery of packets.
ICMP (Internet Control Message Protocol) is an extension of IP. It supports
packets containing error, informational & control message. ICMP command uses
by Ping to test an Internet connection.
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Ports
You may be
wondering what a port is. Do not confuse this type port with the connection
locations on the back of the computer system suck as serial port, parallel port
or RJ 11 & RJ45 (physical port) we discussed earlier. A port, in networking
term, is a handle – a connection point. It is numeric designation for a
particular pathway of communications. All network communication, regardless of
the port used, comes to your computer via connection to your network interface
card.