UNDERSTANDING
WAN (WIDE AREA NETWORK) NETWORK
WAN
(Wide Area Network) is a computer network covering a large area as an example
of computer networks between regions, cities or even countries, or can be
defined as a computer network that requires routers and channels of public
communication . The Internet is an example of this WAN network If the Wide Area
Network already covers the intercontinental area it is called the global
information network or the Internet.
Besides
packet delivery in datagram, IP network is also known as connection packed
packet delivery where before packets are sent, a logical connection setup from
the origin of destination is set by the packet control process with a logical
connection request for a packet of nformations to take the same route. This
connection mode is called a virtual circuit, but unlike circuit switched
networks that occupy the channel (bandwidth / resources) in a monopoly, in the
virtual circuit the use of resources is still in the pattern of sharing. Read
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| Topologi WAN (Wide Area Network) |
That
way packet sequences can be guaranteed, while real-time continuity is not
guaranteed, depending on the capacity and level of traffic density in the
network. This virtual circuit mode enables a group of organizations to have a
virtual private network (called a virtual private network), or a network of PBX
(Private Branch Exchange) but an unlimited range of areas such as PABX because
of the network built in IP VPN not physically but rather logically and
networking only when needed only so that the scope of IP VPN private network
can cover national and even international area.
Another
packet switched based network that is widely developed in the US is the ATM network
(Asynchronus Transfer Mode). The difference is with the IP network, that in the
ATM network overall connection mode using virtual circuit, while on the IP
network, virtual circuit is optional only.Another difference, the packet on the
ATM network is called cell always fixed ie 53 octets (Byte) which consists of
48 octet payload, 5 octet header.
While
in the IP network, packet size is not fixed. ATM technology is widely developed
in the United States (not discussed here). One more thing, that ATM networks
are designed based on broadband services and can accommodate VBR (Variable Bit
Rate) services in addition to CBR (Constant Bit Rate ). While the initial
design of IP networks based on Narrow Band and CBR services.
WAN Network
Concepts
Wide
Area Network (WAN) covers a large geographical area, often including a country
or continent. The WAN consists of a collection of machines that aim to run
these application programs. These machines are hosted. The term End System is
sometimes also used in the literature. The host is connected to a
communications subnet, or simply called a subnet. The task of the subnet is to
carry messages from the host to the other host, just as the telephone system
takes the content of the speaker from the speaker to the listener. By
separating the pure communication aspect of the network (subnet) from the
aspects of the application (host), the complete network design becomes much
simpler.
In
most WANs, the subnet consists of two components, the transmission cable and
the switching element. Transmission cables (also called circuits, channels, or
trunks) move bits from one machine to another.Element switching is a special
computer used to connect two or more transmission cables. When data reaches the
receiver cable, the switching element must select the sending cable to forward
the messages.Unfortunately there is no standard terminology in naming computers
like this. The names vary widely called packet switching nodes, intermidiate
systems, data switching exchange and so on.
As
a generic term for computer switching, we will use the term router. But please
note in advance that there is no consensus in the use of this terminology. In
this model, as shown by the image below each host is connected to the LAN where
there is a router, although in some circumstances a host can be connected
directly to a router. A collection of communication channels and a router (but
not a host) will form a subnet.
The
term subnet is very important, the subnet means a collection of routers and
communication channels that move packets from the destination host host. It
will, however, some years later the subnet gets another meaning in connection
with the network addressing. In most WANs, the network consists of numerous
wires or telephone lines connecting a pair of routers.
If
two routers that do not contain the same cable will communicate, they must
communicate indirectly through other routers. when a packet is sent from one
router to another through an intermediary router or more, then the packet will
be received by the router in a complete state, stored until the output channel
becomes free, and then newly forwarded.
Subnets
that contain such a principle are called point-to-point, store-and-forward, or
packet-switched subnets. Almost all WANs (except those using satellites) have
store-and-forward subnets.
In
using the point-to-point subnet, an important design problem is the selection
of the router's interconnection topology type. LANs are usually symmetric
topologies, whereas WANs are typically erratic.
WAN
(Wide Area Network) Network is a collection of LAN and / or Workgroup connected
by using modem and Internet network communication tools, from / to head office
and branch office, or between branch offices. With this network system,
inter-office data exchange can be done quickly and with a relatively low cost.
This network system can use an existing Internet network, to connect between
headquarters and branch offices or with Stand Alone / Notebook PCs located in
other cities or countries.
Advantages of WAN
Network.
1.
The central office server can function as a data bank from a branch office.
2.
Inter-office communication can use E-Mail & Chat.
3.
Documents / Files typically sent by fax or postal parcel, can be sent via
E-mail and File transfer to / from head office and branch office at relatively
low cost and in a very fast period.
4.
Pooling Data and Updating Data between offices can be done every day at the
specified time.
WAN Network
Connection
To
connect a WAN network we must use a special tool that works as a service
center, such as a VSAT satellite. VSAT is a network or satellite communication
system consisting of a number of remote stations (VSAT terminals) using
parabolic antennas smaller in diameter than other satellite communications,
using one or more satellite transponders as repeaters with the support of
equipment at the station and an earth station main.
WAN
is a collection of multiple LANs that are combined into a new network. Here the
VSAT acts as a connecting medium between a LAN network. So every LAN network is
a terminal station. read also understanding LAN network . WANs cover a large
geographical area, often including a country or continent. In most WANs, the
network consists of two components: transmission cable and element
switching.The transmission cable moves the bits from one machine to
another.Element switching is a special computer used to connect two or more
transmission cables.
In
the WAN system with VSAT media then in addition to the server on each LAN network
there are still other larger servers located on the Hub station. This server
will control the communication between VSAT terminals under it. The server
residing on the terminal station only holds data from the workstations under
it.
The
working system of the WAN is just like the LAN network only if the desired
transfer of data from the user at another VSAT terminal then the server located
on the VSAT terminal will contact the Hub station and Hub will connect to the
desired VSAT terminal so that the desired data transfer can occur . So if the
desired user is contacted only at its own VSAT terminal then the connection to
the Hub station is not done.
In
addition to being used for VSAT network data transfers on WAN configuration can
also be used for video and voice transfer. So the workst station terminals do
not have to use a computer, but can use fax machines or others. The
configuration also has a bit rate is high enough for data transmission, other
than that confidential data is guaranteed as well.
Although
many of the benefits of this WAN system will be ineffective if its use is only
under the number 100. If the use of more than 100 then the system becomes
effective and reliable. In the development of WAN, if the LAN network more and
users (users) are in all parts of the world then the system is called the
Internet.
WAN Network
Infrastructure
Like
LAN (Local Area Network), There are a number of devices that pass the flow of
data information in a WAN. The integration of these devices will create a WAN
infrastructure. These devices are:
1. Router
Router
is the enhancement of the ability of the bridge. Routers are able to show
routes and filter information on different networks. Some routers are able to
automatically detect problems and redirect paths of information from problem
areas.
2. ATM Switch
The
ATM switch provides high speed data transfer between LAN and WAN
3. Modem and CSU /
DSU
Modem
converts digital and analog signals. In the sender, the modem converts the
digital signal into a form suitable for transmission technology to be passed
through analog communications facilities or public telephone line. On the
receiver side, the modem converts the signal to digital format again. also read
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4. CSU / DSU
(Channel Service Unit / Data Service Unit)
CSU
/ DSU is just like a modem, it's just CSU / DSU sending data in digital format
through digital telephone network. CSU / DSU is usually a physical box that is
two separate units: CSU or DSU.
5. Communication
Server
Communication
Server is a special server for users to be able to dial from a remote location so
that it can connect to the LAN.
6. Multiplexer
A
Multiplexer transmits a combination of multiple signals via a
circuit.Multiplexer can transfer some data simultaneously (continuously), such
as video, sound, text, and others.
7. X.25 / Frame
Relay Switches
X.25
and Frame Relay switches connect local / private data over the data network,
using digital signals. This unit is the same as the ATM switch, but the data
transfer rate is lower than the ATM.