The blog includes a vivid coverage of the concepts of CCNA, CCNP (Routing & Switching) , Basic Linux and Linux servers. Projects have also been simulated to give a practical exposure.

Saturday, 23 February 2013

Networking Devices Part 3

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NETWORKING DEVICES
10. GATEWAYS
11. ISDN ADAPTER
12. FIREWALLS
13. MODEMS
14. WIRELESS ACCESS POINT (WAP)
15. PROXY 




 10. GATEWAYS :- A gateway is a device used to connect networks using different protocols.
  • In order to communicate with a host on another network, an IP host must be configured with a route to the destination network. If a configuration route is not found, the host uses the gateway (default IP router) to transmit the traffic to the destination host.
  • If no default gateway is specified, communication is limited to the local network.
  • e.g  E-mail gateways-for example, a gateway that receives Simple Mail Transfer Protocol (SMTP) e-mail, translates it into a standard X.400 format, and forwards it to its destination.

11. ISDN ADAPTER :- ISDN stands for Integrated Services Digital Network.
  • ISDN Adapter can be used to send the voice, data, or video over standard telephone cabling.
  • ISDN adapters must be connected directly to a digital telephone network
  • ISDN adapters are not actually modems, since they neither modulate nor demodulate the digital ISDN signal.
  • ISDN hardware requires a NT (network termination) device, which converts network data signals into the signalling protocols used by ISDN.


fig. ISDN device with ADAPTER

12. FIREWALLS :- Firewall is a piece of hardware and/or software which is used for security purpose.
  • In order to restrict unauthorized access, from outside environment to inside network.
  • Firewall has the basic task to control the traffic between different zones of trust.
fig. Types of Firewall
fig. Firewall

13. MODEMS :- Modem stands for Modulator/Demodulator.

  • MODEM convert digital signal generated by computer into analog signals that can travel over conventional telephone line.
  • Connect to ISP.
  • Dialling up to a LAN.
  • Internal add-in expansion cards or external cards or external devices connect to serial or USB port.PCMCIA cards for Laptops.
  • Speed of the universal Asynchronous Reciever/Transmitter (UART) chip.
  • Types of MODEMS :-  * DSL      * ADSL     * RADSL     * HDSL     * SDSL     * VDSL
 
fig. MODEM

14. WIRELESS ACCESS POINT (WAP) :- Devices that provide connectivity between wireless LAN devices and in most cases a wired network.
  • Antennae
  • convert signal from radio wave or other to that used on the LANs 
Note :- Small wlan can function without access point in so-called 'ad hoc' or peer to peer mode, Access points support 'infrastructure' mode, which bridges with a wired Ethernet land and also scales the network to support more clients.
fig. Wireless Access Point

15. PROXY :- Proxy server is kind of buffer in between our computer and internet resources we are accessing.
  • It is used to access the prohibited or filtered sites by your ISP or institution.
  • It is used to keep the machine anonymous, mainly for security.
  • It is used to prevent the downloading the same content again and again. 
  • It is used to scan the outbound content (for data loss prevention).
  • To check the latest working proxy of the day then check it on site www.samair.ru .
 Made By P & V

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