Showing posts with label Wireless networks. Show all posts
Showing posts with label Wireless networks. Show all posts

Thursday, June 18, 2015

Wireless Networks cont'd

Previous: Wireless LANs

3)Wireless WANs
The radio n/w used for cellular telephones is an example of a low bandwidth wireless system.This system has gone through 3 generations-
1)First generation-analog & voice only
2)Second generation-digital & for voice only
3)Third generation-digital & is for both voice & data

Wireless LANs can operate at 50 Mbps.
Cellular system operate at about 1 Mbps.
Wireless internet service is often called local multipoint distribution service eg.mts
Almost all wireless n/ws hook up to the wired n/w at some point to provide access to files,databases & the internet.
Many n/ws exist in the world,often with different h/w & s/w.
The fulfillment of this desire requires that different & frequently incompatible n/ws be connected by means of machines called gateways to make the connection and provide the necessary translation, both in terms of h/w and s/w called internetwork or internet.
If the system within the gray area contains only routers it is a subnet.
If it contains both routers & hosts it is a WAN.
As an analogy,the telephone system consists of telephone switching offices connected to one another by high speed lines & to houses & business by low speed lines.
These lines and equipment,owned and managed by telephone company form the subnet of telephone system.

Next:Network Connecting Devices

Monday, June 8, 2015

Wireless Networks

Previous

Wireless n/w can be divided into 3 main categories-

1)System interconnection
2)Wireless LANs
3)Wireless WANs

System interconnection
It is all about interconnecting the components of a computer using short-range radio.
Some companies got together to design a short-range wireless n/w called Bluetooth to connect these components without wires.
Bluetooth also allows digital cameras,headsets,scanners and other devices to connect to a computer by merely being brought within range.
System interconnection n/w use the master slave paradigm. The system unit is normally the master,talking to the mouse,keyboard as slaves.
The master tells the slaves what addresses to use,when they can broadcast ,how long they can transmit, what frequencies they can use etc.


Next: Wireless LANs