Computer Architecture And Organization Set 3

Answer: weak or non-existent authentication

Explaination:
weak or non-existent authentication is a vulnerability of the session layer. route spoofing, identity & resource id vulnerability & ip address spoofing are examples of network layer vulnerability.

Answer: physical theft of data

Explaination:
physical theft of data is an example of physical layer vulnerability. other such issues are unauthorized network access, damage or destruction of data & hardware and keystroke & other input logging.

Answer: mac address spoofing

Explaination:
mac address spoofing is an example of data-link layer vulnerability.

Answer: route spoofing

Explaination:
route spoofing is an example of network layer vulnerability. other examples of network layer vulnerabilities are ip address spoofing and identity & resource id vulnerability.

Answer: keystroke & other input logging

Explaination:
keystroke & other input logging is an example of physical layer vulnerability. other such physical layer vulnerabilities are unauthorized network access, damage or destruction of data & hardware and keystroke & other input logging.

Answer: vlan circumvention

Explaination:
vlan circumvention is an example of data-link layer vulnerability. mac address spoofing, as well as switches, may be forced for flooding traffic to all vlan ports are some other examples of data-link layer vulnerability.

Answer: optical fiber

Explaination:
fiber optics is considered to have the highest transmission speed among the all mentioned above. the fiber optics transmission runs at 1000mb/s. it is called as 1000base-lx whereas ieee standard for it is 802.3z. it is popularly used for modern day network connections due to its high transmission rate.

Answer: digital modulation

Explaination:
in analog modulation, digital low frequency baseband signal (digital bit stream) is transmitted over a higher frequency. whereas in digital modulation the only difference is that the base band signal is of discrete amplitude level. the bits are represented by only two frequency levels, one for high and one for low.

Answer: physical signalling sublayer

Explaination:
the portion of physical layer that interfaces with the medium access control sublayer is physical signaling sublayer. the main function of this layer is character encoding, reception, decoding and performs optional isolation functions. it

Answer: all of the mentioned

Explaination:
anything dealing with a network cable or the standards in use – including pins, connectors and the electric current used is dealt in the physical layer (layer 1). physical layer deals with bit to bit delivery of the data aided by the various transmission mediums.

Answer: both start & stop signalling and flow control

Explaination:
in asynchronous serial communication, the communication is not synchronized by clock signal. instead of a start and stop signaling and flow control method is followed. unlike asynchronous serial communication, in synchronous serial communication a clock signal is used for communication, so the start and stop method is not really required.

Answer: all of the mentioned

Explaination:
the physical layer is

Answer: data link layer

Explaination:
physical layer accepts data or information from the data link layer and converts it into hardware specific operations so as to transfer the message through physical cables. some examples of the cables used are optical fiber cables, twisted pair cables and co-axial cables.

Answer: multiplexing

Explaination:
in communication and computer networks, the main goal is to share a scarce resource. this is done by multiplexing, where multiple analog or digital signals are combined into one signal over a shared medium. the multiple kinds of signals are designated by the transport layer which is the layer present on a higher level than the physical layer.

Answer: all of the mentioned

Explaination:
wireless transmission is carried out by radio waves, microwaves and ir waves. these waves range from 3 khz to above 300 ghz and are more suitable for wireless transmission. radio waves can penetrate through walls and are used in radio communications, microwaves and infrared (ir) waves cannot penetrate through walls and are used for satellite communications and device communications respectively.

Answer: orthogonal

Explaination:
in digital communication system, signals from different frequency bands are orthogonal thus interference won’t occur.

Answer: all of the mentioned

Explaination:
some of the properties of impulse function are symmetry, time scaling and shifting.

Answer: all of the mentioned

Explaination:
some of the properties of fourier transform are duality property, time scaling property, time shifting property, modulation property and many more.

Answer: cosine wave

Explaination:
a base-band signal can be up- converted to band-pass filter by applying cosine wave.

Answer: cosine wave

Explaination:
for down-conversion of a band-pass signal also cosine signal is used and multiplied with it.

Answer: low pass filter

Explaination:
downconversion of bandpass signal includes multiplication with sine wave followed by low pass filtering.

Answer: frequency content & bandwidth

Explaination:
fourier transform of a signal give the frequency content and also determines the bandwidth of the signal.

Answer: all of the mentioned

Explaination:
some of the random things in the communication system are noise in the channel, attenuation, fading, channel filtering, device frequency, phase and timing offset.

Answer: fourier transforms

Explaination:
fourier series is limited to only periodic signals where as fourier transforms and laplace transforms can be used for both periodic and non periodic signals.

Answer: zero

Explaination:
a band-pass signal has a fourier transform equal to zero for all value in both frequency and time domain.