Skip to content
Start arrow Articles arrow Basic network devices
Basic network devices
Redaktor: Administrator   
18.04.2010.

Repeater Cisco graphic symbol
Repeater Cisco graphic symbol
REPEATER – device who receive the electrical signal on first port, interpret the bits (1s and 0s), and generate on second port clean from interferences, new and strong signal. A repeater is not just amplifier, because simple amplifying the signal, could amplify any noise and interferences as well. Repeater is considered as device in Layer 1 (does not interpret logical signals, just regenerates electrical signals). Repeaters are used for extending networks over nominal cable length or if is impossible to obtain direct optical visibility for wireless networks based on IEEE 802.11b/g protocols (wireless repeater). To extension of HDSL/SDSL lines uses xDSL repeater - A device similar in price to a pair of modems xDSL because usually it is a couple of modems connected with second one by the network interfaces (e.g. Alcatel 1512PL).

Small Hub and 100BaseT Hub symbols
Small Hub and 100BaseT Hub symbols
HUB – basically it is repeater with multiple physical ports – simply regenerates (not just amplifying, because of possibility amplify interference – see repeater) the electrical signal that comes in one of ports and sends the same signal out every other port – this is one of biggest disadvantages of HUB, because traffic from just one port can blocks all others. All parts of network can receive (packet sniffing is possible – it is the second major disadvantage) packets. Collisions can occur, so CSMA/CD access rules continue to be used. HUBs are used to create star topology with UTP cable. HUBs were much cheaper than more intelligent switches but in last time situation was changed because of production “single-chip” switches.

 

NIC – Network Interface Controller computer hardware to allow computers to communicate over a computer network. It is both an OSI layer 1 (physical layer) and layer 2 (data link layer) device, as it provides physical access to a networking addressing system trough the use of MAC addresses. It allows to connect to each other either by using cables or wirelessly.  

 

To be continued :)

Zmieniony ( 27.04.2010. )
 
Back - Wstecz

Google translate

EnglishFrenchGermanPolishPortugueseRussianSpanishYiddish



Kursy NBP z 03-09-2010
walutaskupsprz. 
USD3.06803.1300st
EUR3.93064.0100st
GBP4.71674.8119st
Kalkulator OC