Network devices
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Transcript of Network devices
Network Devices
Types of Network Devices
Modulator Demodulator (MODEM)
• A device that modulates an
analog carrier signal to encode
digital information, and also
demodulates such a carrier
signal to decode the transmitted information
• The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data
Modulation Techniques
• We basically have three modulation techniques-
• Amplitude Modulation• Frequency Modulation• Phase Modulation
Working of a MODEM
MODEM
DATA COMMUNICATI
ONEQUIPMENT
MODEM
DATA COMMUNICATI
ONEQUIPMENT
DATATERMINAL
EQUIPMENT
DATATERMINAL
EQUIPMENT
TRANSMIT
REQUEST TO SENDRECIEVE
DATA TERMINAL READY
CARRIER DETECT
DATA SET READY
CLEAR TO SEND
Registered Jack 45 (RJ-45)
• An 8-wire connecter, used to connect various Computer systems to LANs
• RJ45 is used almost exclusively to refer to Ethernet (type of LAN system that uses bus or star topology for data sharing) -type computer connectors.
• The RJ-45 connector is commonly used for network cabling and for telephony applications.
Ethernet• Most widely used LAN technology
• Developed by Xerox Corp
• Typically uses coaxial cables and special grades of twisted pair cables
• Ethernet was named by Robert Metcalfe, one of its developers, for the passive substance called "luminiferous (light-transmitting) ether" that was once thought to pervade the universe, carrying light throughout. Ethernet was so- named to describe the way that cabling, also a passive medium, could similarly carry data everywhere throughout the network.
Hub• A device used to connect several computers
together• Is a fairly unsophisticated device as it doesn’t
manage the traffic through it• There are two types of hubs
1) Active Hub2) Passive Hub
Functioning of a Hub• Receives a data packet
• Forwards it to all the remaining ports
Switch• A device used to segment networks into sub-
networks, which prevents traffic overloading in network
• It is a sophisticated device, is responsible for filtering and forwarding data
• In environments where there is a need for a great deal of analysis of network performance and security, there is a provision of a firewall, network intrusion detection and performance analysis modules that can plug into switch ports.
What does it do?• It establishes a temporary connection b/w the source and the destination and then
terminates the connection when conversation is done
Repeater• A device used to expand the boundaries of a
wired or wireless LAN.• Amplify the data signals before sending them on
to the uplinked segment, thereby countering signal decay that occurs over extended lengths of wire.
• Receives a signal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.
• Over distance, cables connecting a network lose the signal transmitted. If it degrades too much, it fails to reach its destination.
• These are of 2 types:AmplifierSignal repeater
• Connects multiple network segments.
• Similar to repeaters or network hubs, however, can manage data from one network rather than simply rebroadcast to adjacent network segments.
• Analyze incoming data packets to determine if the bridge is able to send the given packet to another segment of the network.
Bridge
Advantages and Disadvantages ADVANTAGES OF
BRIDGESDISADVANTAGES OF
BRIDGESSimple bridges are
inexpensiveDoes not scale to extremely large
networksLANs interconnected
are separateBuffering and
processing introduces delays
Helps minimize bandwidth usage
Bridges are more expensive than
repeaters or hubs
Router• Device that interconnects two or more computer
networks, and selectively interchanges packets of data between them
• It works like a bridge but can handle diff. protocols• Each data packet contains address information that a
router can use to determine if the source and destination are on the same network, or if the data packet must be transferred from one network to another
• In case of an unknown destination, a router sends the traffic to another router
Gateway• Has the ability to connect dissimilar networks
• Acts as an entrance to a network • Generally, a gateway node is often also acting
as a proxy server and a firewall server, blocking an unauthorized access to or from a private network.