NETWORKING SUMMATIVE REVIEWER

Baseband transmission –

one in which the entire channel capacity of the cable medium is used by one data signal. In BLANK transmission, the original data signal occupies the entire available bandwidth of the channel.

Broadband transmission –

employs several transmission channels on a single communication medium. This allows more than one node to transmit at the same time. Broadband uses modulation techniques to send data over multiple frequency channels.

Bandwidth –

the capacity of a channel to transmit data in terms of given speed. It refers to the capacity or data transfer rate of a telecommunications or network channel. It represents the maximum amount of data that can be transmitted over a communication channel in a given amount of time, usually measured in bps, Kbps, Mbps, or Gbps.

Twisted-Pair Cable –

consists of color-coded pairs of insulated copper wires twisted around each other to reduce noise and crosstalk.

Shielded Twisted Pair (STP)

– consists of insulated solid wire pairs surrounded by shielding.

Braided shielding –

used for indoor wiring; protects from external EMI.

Corrugated shielding –

used for outdoor/underground wiring; stronger EMI/RFI protection.

Unshielded Twisted Pair (UTP) 

– wire pairs within an insulated outside covering without shielding. Less expensive, less resistant to noise.

Connector (STP/UTP) –

use RJ-45 connectors; telephones use RJ-11.

TIA/EIA Standard

– telecommunications standards defining T568A and T568B wiring schemes.

T568A –

pin order: white green, green, white orange, blue, white blue, orange, white brown, brown.

T568B –

pin order: white orange, orange, white green, blue, white blue, green, white brown, brown.

Straight Through –

connects different devices (PC to switch).

Cross-over –

connects same devices (switch to switch, PC to PC).

Roll-over –

console cables; pin 1 on one side is opposite pin 8 on the other.

Coaxial Cable (Coax) –

consists of solid copper core with insulation and shielding. Longer distance, higher speed, better shielding.

Thick Coaxial Cable (Thicknet, RG-8, 10Base5) –

0.4-inch diameter, 500m max.

Thin Coaxial Cable (Thinnet, 10Base2) –

0.2-inch diameter, 200m max.

BNC Connector (Bayonet Nut Connector)–

connects coaxial cables; T connectors branch cables; terminators prevent signal reflection.

Fiber Optic Cable – 

glass/plastic fiber cores transmit data as light pulses via lasers or LEDs. Supports 100 Mbps to 100+ Gbps.

Single-Mode Fiber –

8–10 micron core, long-distance (up to 70 km), uses laser light.

Multi-Mode Fiber –

50 micron core, shorter distance (up to 2 km), uses LED.

Step Index –

light reflects zigzag inside core.

Graded Index –

light follows curved path, signals arrive together.

Fiber Connectors –

SC (cable TV), ST (networking, bayonet lock), MT-RJ (same size as RJ45).

Unguided Media (Wireless) –

uses electromagnetic waves without physical conductor.

Radio Wave

– omnidirectional, penetrates buildings, used in radios, cell phones, Wi-Fi, GPS.

Microwave –

unidirectional, line-of-sight, requires tall towers, cannot penetrate walls. Uses parabolic or horn antennas.

Infrared –

short-range, directional, cannot penetrate walls. Used in remotes, detectors, cordless devices.

Transmission Mode –

the way data is transmitted between devices.

Simplex –

one-way communication (keyboard to monitor).

Half-duplex –

two-way but not simultaneous (walkie-talkie).

Full-duplex –

two-way simultaneous (telephone).

Unicast –

one sender to one receiver.

Multicast –

one/more senders to specific group of receivers.

Broadcast –

one sender to all receivers.

Multiplexing

is the process of combining multiple signals into one signal, over a shared medium. The process of combining the data streams is known as multiplexing. If analog signals are multiplexed, it is Analog Multiplexing and if digital signals are multiplexed, that process is Digital Multiplexing.

Multiplexer (MUX)

Multiplexing is achieved by using a device called BLANK that combines n input lines to generate a single output line. Multiplexing follows many-to-one, i.e., n input lines and one output line.

De-multiplexer (DEMUX)

Demultiplexing is achieved by using a device called BLANK available at the receiving end. DEMUX separates a signal into its component signals (one input and n outputs). Therefore, we can say that demultiplexing follows the one-to-many approach.

Multiplexer

is a device that has multiple inputs and a single line output. The select lines determine which input is connected to the output, and also to increase the amount of data that can be sent over a network within certain time.

De-multiplexer

is also a device with one input and multiple output lines. It is used to send a signal to one of the many devices.

George Owen Squier

developed the telephone carrier multiplexing in 1910.

telephone carrier multiplexing

George Owen Squier developed the Blank  in 1910.

Composite signal

is a combination of two or more simple sine waves with different frequency, phase and amplitude.

The analog multiplexing techniques

involve signals which are analog in nature. The analog signals are multiplexed according to their frequency (FDM) or wavelength (WDM).

Frequency Division Multiplexing FDM

In analog multiplexing, the most used technique is BLANK. This technique uses various frequencies to combine streams of data, for sending them on a communication medium, as a single signal. A number of signals are transmitted at the same time, and each source transfers its signals in the allotted frequency range.

Frequency Division Multiplexing

is a technique in which the available bandwidth of a single transmission medium is subdivided into several channels.

Modulation

is the process of converting data into electrical signals optimized for transmission. BLANK techniques are roughly divided into four types: Analog modulation, Digital modulation, Pulse modulation , and Spread spectrum method

Wavelength Division Multiplexing

is an analog technique, in which many data streams of different wavelengths are transmitted in the light spectrum. If the wavelength increases, the frequency of the signal decreases.

digital

The term BLANK represents the discrete bits of information. Hence the available data is in the form of frames or packets, which are discrete.

Time Division Multiplexing (TDM)

in BLANK the time frame is divided into slots. This technique is used to transmit a signal over a single communication channel, with allotting one slot for each message.

Time Division Multiplexing (TDM)

in BLANK the total time available in the channel is distributed among different users. Therefore, each user is allocated with different time interval known as a Time slot at which data is to be transmitted by the sender.

Synchronous TDM

is a technique in which time slot is preassigned to every device.  In BLANK, each device is given some time slot irrespective of the fact that the device contains the data or not.  If the device does not have any data, then the slot will remain empty.  In BLANK, signals are sent in the form of frames. Time slots are organized in the form of frames.  If a device does not have data for a particular time slot, then the empty slot will be transmitted.

statistical division multiplexing.

Other name of asynchronous TDM is?

Asynchronous TDM

It is a technique in which time slots are not fixed as in the case of Synchronous TDM.  Time slots are allocated to only those devices which have the data to send.  Therefore, we can say that BLANK transmits only the data from active workstations.  If the allotted device, for a time-slot, transmits nothing and sits idle, then that slot is allotted to another device, unlike synchronous.

asynchronous time division multiplexing

In BLANK, the multiplexer scans all the devices (transmitters) and accepts input only from the devices that have actual data to send and fills all the frames, and then sends it to the receiver.

Switching

is a mechanism by which data/information sent from source towards destination which are not directly connected. Networks have interconnecting devices, which receives data from directly connected sources, stores data, analyze it and then forwards to the next interconnecting device closest to the destination.

Switching

When a user accesses the internet or another computer network outside their immediate location, messages are sent through the network of transmission media. This technique of transferring the information from one computer network to another network is known as BLANK

Ingress

When data comes on a port it is called

Egress.

when data leaves a port or goes out it is called

circuit switching

When two nodes communicate with each other over a dedicated communication path, it is called BLANK. There is a need of pre- specified route from which data travels and no other data is permitted. In circuit switching to transfer the data, circuit must be established so that the data transfer can take place.

Circuit switching

is a switching technique that establishes a dedicated path between sender and receiver.

Message Switching

is a switching technique in which a message is transferred as a complete unit and routed through intermediate nodes at which it is stored and forwarded.

store and forward network.

Each and every node stores the entire message and then forward it to the next node. This type of network is known as

Packet Switching

The BLANK is a switching technique in which the message is sent in one go, but it is divided into smaller pieces, and they are sent individually.  It breaks data into packets, small units of data, which are individually routed from source to destination.