CS8601 mobile computing Two marks Questions and Answer

CS8601-Mobile Computing-
Questions & Answers
Dr. M.Kaliappan,M.E.,Ph.D
Associate Professor/CSE
Ramco Institute of Technology, Rajapalayam, Tamilnadu, India
Acknowledgement
1. Credit: Jochen Schiller, “Mobile Communication”, PHI, Prasant Kumar Pattnaik,
Rajib Mall, “Fundamentals of Mobile Computing”, PHI
2. Credit: Prasant Kumar Pattnaik, Rajib Mall, ―Fundamentals of Mobile Computing‖,
PHI Learning Pvt.Ltd, New Delhi – 2012
3. Credit: Internet resources

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DEPT OF CSE, RAMCO INSTITUTE OF TECHNOLOGY, RAJAPALAYAM-626117
CS8601-Mobile Computing – Questions & Answers 2019-2020
UNIT-I- INTRODUCTION
1) What is Mobile Computing? [CO1 – L1]
Mobile computing is widely described as the ability to compute remotelywhile on the
move. This is a new and fast emerging discipline that has made itpossible for people to access
information from anywhere and at any time.
It sometimes called ubiquitous computing and also at times called nomadic
computing
Mobile computing as encompassing two separate and distinct concepts:
 Mobility and Computing.
2) Define computing? [CO1 – L1]
Computing denotes the capability to automatically carry out certain processing
related to service invocations on a remote computer.
3) Define Mobility? [CO1 – L1]
Mobility, on the other hand, provides the capability to change location
whilecommunicating to invoke computing services at some remote computers.
4) What is main advantage and Disadvantage of mobile computing? (May/june
2015)[CO1 – L1]
Advantage:-
The tremendous flexibility it provides to the users.
The user need not be tethered to the chair in front of his desktop, but can movelocally or
even to faraway places and at the same time achieve what used tobe performed while sitting
in front of a desktop.
 Location Flexibility
 Saves Time
 Enhanced Productivity
 Ease of Research
 Entertainment
 Streamlining of Business Processes
Disadvantages:–
 Expensive
 Power Consumption
 Small Screen Display
 Slow Internet Speed
 Risky to carry
 Security Concerns
 Communication depends upon network connectivity
5) Distinguish Mobile Computing vs. Wireless Networking [CO1 – L2] (Nov/Dec 2017)
(Apr/May 2017)
Mobile Computing Wireless Networking
It is a technology that access data
through wireless network
It is a network that uses wireless data
connections for connecting network
nodes

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It refers to a device performing computation
that is not always connected to a central
network
It refers to the data communication without
the use of a landline. Eg. Cellular Telephone,
Two way radio, Satellite, Wireless
Connection
It denotes accessing information and
remote computational services while on the
move
It provides the basic communication
infrastructure necessary for mobile
computing
It refers to computing devices that are
not restricted to a desktop. Eg: Smart
Phone, PDA, Laptop etc
It is a method of transferring information
between a computing devices such as PDA &
data sources without a physical connection
6) List out various forms of Wireless networks? [CO1 – L1]
Wireless networks appear in various forms such as
 WLANs (Wireless LANs),
 Mobile Cellular Networks,
 Personal Area Networks (Pans),
 Ad Hoc Networks, etc.
7) What are the two basic types of wireless network? [CO1 – L1]
i) Extension of Wired Networks: Uses fixed infrastructures such as base stations to
provide single hop wireless communication (or) two-hop wireless communication.
a. Example: WLAN, Bluetooth
ii) Adhoc Networks: It does not use any fixed infrastructure and it is based on multi-
hop wireless communication.
Example: MANET, VANET.
8) List out types of computer network? [CO1 – L1]
Several types of computer networks are in use today.
 Personal Area Network (PAN)
 Local Area Network (LAN)
 Wireless Local Area Network (WLAN)
 Controller Area Network (CAN)
 Metropolitan Area Network (MAN)
 Wide Area Network (WAN)
 Storage-Area Network (SAN)
 Internetworks
9) Define CAN? [CO1 – L1]
A Controller Area Network (CAN) is essentially a very small network that is typicallyused to
connect the different components of an embedded controller.
The end-to-end length of a CAN is usually less than 50 metres. Since the propagationtime of
a CAN is very small, it behaves more like alocal bus in a computer.
10) Define LANs? [CO1 – L1]
A Local Area Network (LAN) is typically deployed in a building or a campus and is
usuallyprivately owned.

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For example, a LAN can be used to connect a number of computers within anorganization to
share data and other resources such as files, printers, FAX services, etc.
LANs typically operate at data rates exceeding 10 Mbps and many present-day LANs(gigabit
Ethernets) operate at 1 Gbps.
11) Define Internetwork? [CO1 – L1]
Several LANs can be interconnected using switches to realize internetworks orinternet in
short. In an internet, a node in a LAN communicates with a node in anotherLAN using packet
switching.
12) Listout Component of wireless System? [CO1 – L1]
A wireless communication system is built from various types of basic components.
The following are some of these basic types of components.
 Transmitter
 Receiver
 Antenna
 Filters
 Amplifiers
 Mixers
13) Write short notes about WLANs? Wireless Local Area [CO1 – L3]
Networks (WLANs) provide connectivity between computers over shortdistances using the
wireless medium.
Typical indoor applications of WLANs may be in educational institutes, officebuildings and
factories where the required coverage distances are usually restricted toless than a few
hundred feet.
14) Brief about Access point? [CO1 – L2]
 It is a radio receiver/transmitter (also called transceiver) that connects tothe wired
network. These are typically mounted on the roofs at different locations of abuilding.
 You can spot them if you carefully observe the roof of a building having wireless
LAN.
 The transceiver exchanges signals with the wireless LAN card in desktop or
notebookPCs.
 A single access point can support a small group of users. It is connected to a
wirednetwork through cables and provides the connectivity between wireless devices
and thewired network.
15) Write short notes about Wireless LAN cards? [CO1 – L3]
Wireless LAN cards: End-users access the WLAN through WLAN adapters
(wirelessnetwork interface cards) in their hand-helds. The LAN card used to be mounted on
themotherboard of a computer. Now, it is inbuilt into the motherboards.
16) Define Bridge? [CO1 – L1]
Bridge: It is used for connecting two LANs that may be in two different buildingsor
on two separate floors within the same building.

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17) Write Advantages of Wireless LANs over Wired LANs? [CO1 – L1]
1. Mobility- users get information at any place
2. Simplicity and speedy deployment
3. Flexibility: Wireless technology allows the network to be accessible wherewiring is
difficult to lay
4. Cost effectiveness
18) Write Bluetooth technology? [CO1 – L1]
Bluetooth is a wireless technology standard for exchanging data over short
distances(using short- wavelength UHF radio waves in the ISM band from 2.4 to 2.485
GHz)from fixed and mobile devices, and building personal area networks (PANs)
19) Define PANs? [CO1 – L1]
A personal area network (PAN) is a computer network used for data
transmissionamong devices such as computers,telephones and personal digital assistants.
PANscan be used for communication among the personal devices themselves
(intrapersonalcommunication)
20) What is piconet? [CO1 – L2]
A piconetis a computer network which links a wireless user group of devices
usingBluetooth technology protocols. A piconet consists of two or more devices occupying
thesame physical channel (synchronized to a common clock and hopping sequence). Itallows
one master device to interconnect with up to seven active slave devices.
21) What will the master and slave? [CO1 – L2]
Master/slave is a model of communication where one device or process hasunidirectional
control over one or more other devices. In some systems a master isselected from a group of
eligible devices, with the other devices acting in the role ofslaves.
22) Describe Mobile ad hoc network? [CO1 – L2]
An ad hoc network is also known as a Mobile Ad hoc Network (MANET). It is
acollection of mobile nodes that form a network on the fly without requiring the supportof
any fixed infrastructure.Wireless sensor networks are a special type of wireless adhoc
networks.
23) List out the Characteristics of Mobile computing? [CO1 – L2]
 Ubiquity
 Location awareness
 Adaptation
 Broadcast
24) Listout the three tiers of a mobile computing application? [CO1 – L2]
User interface/Presentation tier
 User facing device handling and rendering
Process management/Application tier
 Business logic and rules are executed
Data management/Data tier
 Database access and management

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25) Write about MAC protocol? [CO1 – L2]
MAC protocol is to enforce discipline in the access of a shared channel whenmultiplenodes
contend to access that channel. At the same time, two other objectives of anyMAC protocol
are maximization of the utilization of the channel and minimization ofaverage latency of
transmission.
However, a MAC protocol must be fair and ensure that no node has to wait for anunduly long
time, before it is allowed to transmit.
26) Write some of issues of MAC protocol? [CO1 – L2]
 Hidden Terminal Problems
 Exposed Terminal Problems
 Design issues of MAC protocol
o node mobility; an error- prone, broadcast and shared channel;
o time-synchronization;
o bandwidth efficiency;
o QoS support
27) List out classification of MAC protocol? [CO1 – L2]
(i) Fixed assignment schemes-
(ii) Random assignment schemes
(iii) Reservation-based schemes
28) Define fixed assignment schemes? [CO1 – L1]
In fixed assignment schemes, the resources required for a call are assigned
fortheentire duration of the call.
29) Define random assignment schemes? [CO1 – L1]
Random assignment schemes are comparable to the connection-less packets
witchingschemes. In this, no resource reservations are made, the nodes simply startto transmit
as soon as they have a packet to send.
30) Define reservation assignment schemes? [CO1 – L1]
A node makes explicit reservation of the channel for an entire call beforetransmitting. This is
analogous to a connection-based packet-switching scheme.
31) Explain hidden and exposed terminal problems in infrastructure-
lessnetwork.(May/June 2015) [CO1 – L2]
The hidden terminal analogy is described as follows:
 Terminal A sends data to B, terminal C cannot hear A
 Terminal C wants to send data to B, terminal C senses a "free"' medium(CS fails) and
starts transmitting
 Collision at B occurs, A cannot detect this collision (CD fails) and continues with
itstransmission to B
 Terminal A is "hidden" from C and vice versa.
The exposed terminal analogy is described as follows:
 B sends to A, C wants to send to another terminal D not A or B
 C senses the carrier and detects that the carrier is busy.

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 C postpones its transmission until it detects the medium as being idle again
 But A is outside radio range of C, waiting is not necessary
 C is “exposed" to B
32) What are the limitations of Mobile Computing? (Nov/Dec 2016) [CO1 – L2]
 Insufficient bandwidth
 Security standards
 Power consumption
 Transmission interferences
 Potential health hazards
 Human interface with device
33) What is the different Random Assignment Scheme in MAC? (Nov/Dec 2016) [CO1–
L2]
 ALOHA
 Slotted ALOHA
 CSMA
 CSMA/CD
 CSMA/CA
34) What are the applications of mobile computing? [CO1 – L1]
 Emergency services
 Stock Broker
 Vehicles
 For Estate Agents
 In courts
 In companies
 Stock Information Collection/Control
 Credit Card Verification
 Taxi/Truck Dispatch
 Electronic Mail/Paging
34. Specify the functionalities of Application Tier. [CO1 – L1]
 Responsible for making logical decisions and performing calculations.
 Moves and Process data between the presentation and data layers.
36. What is the use of Data Tier? [CO1 – L1]
 Responsible for providing the basic facilities of data storage, access and
manipulation.
 Contains a database where the information is stored and retrieved.
37. What is meant by Hidden Node and Exposed Node? [CO1 – L1]
 Hidden Node: A hidden node is a node that does not hear the transmission that a node
within its range is receiving and thus does not attempting to gain access.
 Exposed Node: An exposed node is a node that hears multiple disjoint sections of a
network and never gets an opportunity to compete for transmission since it is always
deferring to someone.

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38. Which TDMA scheme is suitable for satellite system? (May/June 2014) [CO1 – L1]
 Time Division Multiple Access or TDMA is a method used to enable multiple
earth stations or VSAT terminals to transmit intermittently on the same frequency,
but with the timing of their transmissions so arranged that the bursts do not
overlay when they arrive at the satellite but arrive in sequence and thus are all
successfully received.
39. Why can’t wireless LAN implement CSMA/CD? (May/June 2012) [CO1 – L1]
In CSMA/CD technique, the sender starts to transmit if it senses the channel to
be free but not on the receiver side. The sender detects no collision and assumes that
the data has been transmitted without errors, but a collision might actually have
destroyed the data at the receiver. It is very difficult for a transmitting node to detect a
collision, since any received signal from other nodes would be too weak compared to
its own signal and can be masked by noise easily. Thus, CSMA/CD can‟t be
implemented in wireless LAN.
40. Why wireless LAN services are of lower quality than wired LAN? (May/June 2014)
[CO1 – L1]
In wired LAN, same signal strength can be assumed all over the wire if the
length of the wire stays within certain often standardized limits, whereas in wireless
LAN, the signal strength decreases proportionally to the square of the distance to the
sender. Obstacles weaken the signal strength further. Therefore, wireless LAN
services are of lower quality than wired LAN.
41. Compare CSMA / CD and CSMA / CA. [CO1 – L2]
CSMA / CD CSMA / CA
It takes effect after a collision It takes effect before a collision
It will not take steps to prevent transmission
collision until it is taken place
It will take actions not to take place any
collision
It only minimizes the recovery time It reduces the possibility of a collision
Typically used in wired networks Typically used in wireless networks &
WLANs
Standardized in IEEE 802. 3 Standardized in IEEE 802.11
24. Formulate a reason why Collision Detection is based protocol not suitable for
wireless networks? [CO1 – L1]
Because, in a wireless network, it is very difficult for a transmitting node to detect a collision,
since any received signal from other nodes would be too weak compared to its original signal
and can easily be masked by noise. As a result the transmitting node would continue to
transmit the frame which leads to corrupted frame.
In wired network, when a node detects a collision, it immediately stops transmitting, thereby
minimizing channel wastage.
25. Assess why the MAC protocol is designed for infrastructure based wireless N/W
may not work satisfactory in infrastructure-less environment. Justify your answer?
[CO1 – L2]
Because,
 It is for a transmitting node to detect collisions

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 Hidden and Exposed terminal problems makes MAC protocols inefficient.
26. Multiplexing (2 Marks)
• Multiplexing describes how several users can share a medium with minimum or no
interference.
• The task of multiplexing is to assign space, time, frequency, and code to each
communication channel with a minimum of interference and a maximum of medium
utilization.
27. What are the types of Multiplexing ?
• Space division multiplexing
• Frequency division multiplexing
• Time division multiplexing
• Code division multiplexing
28. What is Space division multiplexing ?
The term communication channel refers to an association of sender(s) and receiver(s)
who want to exchange data. It represents channels ki and introduces a three dimensional
coordinate system such as code c, time t and frequency.
28. What is Guard space ?
The space between the interference ranges is sometimes called guard space.
• EX: Telephone Exchange system
– Each subscriber is given a separate pair of copper wires to the local exchange
29. What are the Disadvantages of SDM ?
SDM implies a separate sender for each communication channel that clearly
represents a waste of space
30 What is Frequency division multiplexing (FDM)?
• It subdivides the frequency dimension into several non-overlapping frequency bands.
• Each channel ki is now allotted its own frequency band.
• Senders using a certain frequency band continuously.
Advantages
• This scheme does not need coordination between sender and receiver: the receiver only
has to tune in to the specific sender
31. What are the Disadvantages of FDM ?
• While radio stations broadcast 24 hours a day, mobile communication typically takes
place for only a few minutes at a time.
• Assigning a separate frequency for each communication scenario would be a waste of
(scarce) frequency resources.
• Additionally, the fixed assignment of a frequency to a sender inflexible and limits the
number of senders.
32. What is Time division multiplexing
In time division multiplexing (TDM), a channel ki is given the whole bandwidth for a
certain amount of time, i.e., all senders use the same frequency but at different points in
time.
Disadvantages
• It needs complex coordinating system to avoid interference. In which all senders
need precise clocks or, distribute a synchronization signal to all senders.
• A receiver listens at exactly the right point in time.

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Advantages
• This scheme is flexible as one can assign more sending time to senders with a
heavy load and less to those with a light load
33. What is Code division multiplexing?
Code division multiplexing (CDM) is a new scheme in commercial communication
systems. All channels ki use the same frequency at the same time for transmission.
Separation is achieved by assigning each channel its own „code‟,
• Advantages
It gives good protection against interference and tapping. Different codes have to be
assigned.
Assigning individual codes to each sender does not usually cause problems.
• Disadvantages
• A receiver has to know the code and must separate the channel with user data from the
background noise composed of other signals and environmental noise.
• Additionally, a receiver must be synchronized with the transmitter to apply the
decoding correctly.
34 Spread spectrums
Spread spectrum techniques involve spread across a wide bandwidth needed to
transmit data
35. What are the advantages of Spread Spectrum ?
– Cross-talk elimination
– Better output with data integrity
– Better security
– Reduction in noise
– Not easy to demodulate/decode
36. What are the disadvantages of Spread Spectrum
• Increased complexity of receivers that have to despread a signal.
• The large frequency band that is needed due to the spreading of the signal.
• Spread signals appear more like noise; they still raise the background noise
level.
37. What are the types of spread spectrum ?
• Frequency Hopping Spread Spectrum(FHSS)
• Direct Sequencing Spread Spectrum(DSSS)
38. What is Frequency Hopping Spread Spectrum (FHSS) ?
In frequency hopping spread spectrum (FHSS) systems, the total available
bandwidth is split into many channels of smaller bandwidth plus guard spaces between the
channels.
39. What is Dwell time?
The time spend on a channel with a certain frequency in the frequency hopping spread
spectrum is called the dwell time

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40 What are the types of FHSS?
• Slow hopping
• Fast hopping
41. Applications of FHSP or spread spectrum (2 marks)
– Military use
– Bluetooth
– Walkie-Talkies
– Other radios
• Ex YouTube Video: https://www.youtube.com/watch?v=CkhA7s5GIGc
42 What is Direct sequence spread spectrum ?
• In Direct sequence spread spectrum (DSSS), a user bit stream XOR with a
sequence pattern or spreading factor. It is called chipping sequence. While each user
bit has a duration tb, the chipping sequence consists of smaller pulses, called chips,
with a duration tc. If the chipping sequence is generated properly that is called
pseudo-noise sequence.
43 What is Digital modulation and radio modulation ?
• The spreading of the user data with the chipping sequence.
Radio modulation (2 Marks)
• The spread signal is then modulated with a radio carrier
44 Wappens in case of multi-path propagation?
• Several paths with different delays exist between a transmitter and a receiver.
Additionally, the different paths may have different path losses.
• In this case, rake receivers are used to provide a possible solution. It take advantage of
the multi-path propagation by combining the different paths.
• A rake receiver uses n correlators for the n strongest paths. Each correlator is
synchronized to the transmitter plus the delay on that specific path.
• As soon as the receiver detects a new path which is stronger than the currently
weakest path, it assigns this new path to the correlator with the weakest path.
– The output of the correlators are then combined and fed into the decision unit.
45. Comparison between FHSS and DSSS
FHSS DSSS
Multiple frequencies are used Single frequency is used
Frequency reuse is allowed Frequency reuse is not allowed
Sender need not wait Sender has to wait if the spectrum is busy
Power strength of the signal is high Power strength of the signal is low
It is never affected by interference It can be affected by interference
It is cheaper It is expensive

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46. What is MAC protocol ?
• It enforces the discipline in the access of shared medium when multiple user content
to access that channel.
• The objectives of MAC protocol are maximization of the utilization of the channel
and minimization of the average latency of the transmission.
• MAC (Medium access control) protocol is sub layer of data link layer, it directly
invoke the physical layer.
57 What are the Properties of MAC protocol ?
• It helps maximize the utilization of channel
• Channel allocation need to be fair
• Support different types of traffic having different and average bitrate
• It should be robust when equipment failure and change network condition
• It enforce the discipline in the access of shared medium from multiple user
• 802.11 is the standard for MAC protocol
• –EX: 802.11 network card, router
58. What are the functionalities of MAC protocol?
• Roaming
• Point Coordination function
• power conservation
• Authentication
59. What are the Taxonomy of MAC protocols ?
• Fixed assignment schemes
• Random assignment schemes
• Reservation based assignment schemes
60 What are the types of Fixed assignment schemes?
– Frequency division multiple access(FDMA)
– Time division multiple access(TDMA)
– Code division multiple access(CDMA)
61 What are the advantages and disadvantages of Frequency division multiple
access(FDMA)?
Advantages
• Reduces the bit rate information
• It reduces the cost and lowers the inter symbol interference
• An FDMA system can be easily implemented.
• Since the transmission is continuous, less number of bits are required for
synchronization and framing
Disadvantages
• The maximum flow rate per channel is fixed and small
• Guard bands lead to a waste of capacity.
• Unused transmission time occurs when the user pauses between the transmission, it
does not achieve the high channel utilization
62 What are the advantages and disadvantages of TDMA ?
Advantages
– Permits flexible data rates.
– No guard band required for the wideband system.
Disadvantages

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– Call time is needed in each slot to accommodate time to inaccuracies (due to
clock instability).
– Electronics operating at high bit rates increase energy consumption.
– Complex signal processing is required to synchronize within short slots.
63 What is Code Division Multiple Access (CDMA)?
• CDMA is a sort of multiplexing that facilitates multiple users to occupy a single
transmission channel. It optimizes the use of available bandwidth.
• Multiple users are allotted different code(sequence of 0 and 1) to access same channel
• Special coding scheme is used that allows signal from multiple users to be
multiplexed over the channel. Multiple users use the same frequency at the same time
64. What are the advantages and disadvantages of TDMA ?
Advantages
• CDMA provide a power control
• Flexible transfer may be used.
• Reduces interference.
Disadvantages
• The code length must be carefully selected. A large code length can induce delay or
may cause interference.
• Time synchronization is required.
65 What is Space Division Multiple Access (SDMA) ?
It is used for allocating a separated space to users in wireless networks. SDMA is
always in combination with one or more other schemes.
66. What are the Problem of Slotted ALOHA ?
– The random retransmission of the packet will have an effect on the delay
associated with successful packet delivery.
– If the limit is too short, the probability of re-collision is high.
– If the limit is too long the probability of re-collision less but there is
unnecessary delay in the retransmission.
UNIT II
MOBILE TELECOMMUNICATION SYSTEM

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1. Define GSM.[CO3 – L1]
Global System for Mobile Communication (GSM) is a wide area wireless
communications system that uses digital radio transmission to provide voice, data and
multimedia communication services. A GSM system coordinates the communication
between a mobile telephones (Mobile Stations), base stations (Cell Sites) and switching
systems.
2. List the services provided by GSM[CO3 – L1]
 Bearer Services
 Teleservices
 Supplementary services
3. State Bearer Services[CO3 – L2]
The GSM data services are named as bearer services. Bearer services give the
subscribers the capability to send and receive data to/from remote computers or mobile
phones. Besides supporting SMS, email, voice mailbox, and Internet access, this service
provides user with the capability to execute remote applications.
4. Differentiate Transparent Bearer Services and Non-transparent bearer
services[CO3 – L3]
Transparent Bearer Services Non-transparent bearer services
Uses the function of physical layer of
transmission of data leading to constant
delay and throughput if no transmission
errors occur.
Uses protocols of the second and third
layers to implement error correction and
flow control.
FEC (Forward error correction) is used to
increase the quality of data transmission
They use transparent bearer services in
addition to a Radio Link Protocol (RLP).
This protocol comprises mechanisms of
high level data link control.
5. Enlist the teleservices offered by GSM[CO3 – L2]
 GSM provides both
 Voice-oriented teleservices
 Non-voice teleservices
6. Write the supplementary services offered by GSM. [CO3 – L1]
GSM provides supplementary services such as user identification, call redirection and
forwarding of on-going calls. In addition, standard ISDN features such as „close user
groups‟ and „multiparty‟ communication are available.
7. Name the subsystems in GSM system. [CO3 – L1]
GSM consists of three main subsystems
 Radio Subsystem (RSS)
 Networking and Switching Subsystem (NSS)
 Operation Subsystem (OSS)
8. List the components of Radio Subsystem (RSS). [CO3 – L2]
Radio Subsystem (RSS) includes the mobile stations (MS), base station subsystems,
base transceiver station and base station controller.

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9. List the databases of NSS in GSM[CO3 – L2]
 Home location register
 Visitor location register
 Authentication centre
10. Enlist the functions of OSS in GSM [CO3 – L2]
 Manage all charging and billing procedures
 Manage all mobile equipment in the system
11. What are the security services of GSM? (Or) [CO3 – L1]
List the three important features of GSM security. (May/June 2016)
 Access control and authentication
 Confidentiality
 Anonymity
12. Define beacon [CO3 – L1]
A beacon contains a timestamp and other management information used for power
management and roaming. e.g., identification of the base station subsystem (BSS).
13. What is the information in SIM? [CO3 – L1]
 card type,
 serial no,
 list of subscribed services
 Personal Identity Number(PIN)
 Pin Unlocking Key(PUK)
 An Authentication Key(KI)
14. What are the basic units of a Cellular system? [CO3 – L1]
 Mobile stations
 Base stations
 Mobile Switching Center (MSC) or Mobile Telephone Switching Office (MTSO).
15. What are the limitations of conventional mobile telephone system? [CO3 – L1]
 Limited service capability
 Poor service performance
 Inefficient frequency spectrum utilization
16. Mention the function of the base station. [CO3 – L1]
The base station serves as a bridge between all mobile users in the cell and connects
the simultaneous mobile calls via telephone lines or microwave links to the mobile
switching center(MSC)
17. What are the functions of MSC? [CO3 – L1]
The MSC coordinates the activities of all the base stations and connects the entire
cellular system to the PSTN.
18. What is mobility management? [CO3 – L1]

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Mobility management refers to the operations required for tracking the mobile and
restructuring existing connections as it moves. Mobility management consists of Location
management and Handoff management
19. Define location management and handoff management. [CO3 – L1]
 Location management refers to the activities a wireless network should perform in
order to keep track of where the mobile is.
 Handoff management handles the messages required to make the changes in the fixed
network to handle the change in location during an on-going communication.
20. What is meant by GPRS? [CO3 – L1]
General packet radio services, a technology for radio transmission of small packets of
data, esp. between cellular phones and the Internet
21. What do you mean by roaming? [CO3 – L1]
Extending the connectivity service in a location that is different from the home
location where the service was registered. Roaming ensures that the wireless device is
kept connected to the network, without losing the connection.
22. State the role of NSS[CO3 – L2]
NSS stands for Network and switching subsystem. This subsystem forms the heart of
the GSM system. It connects the wireless networks to the standard public networks and
carries out usage-based charging, accounting, and also handles roaming. NSS consists of
switching centre and several databases.
23. Distinguish between HLR and VLR. [CO3 – L3]
HLR VLR
HLR stands for Home Location Register VLR stands for Visitor Location Register
HLR is a mobile operator database that
includes details specific to each subscriber
such as phone number, subscriber‟s IMSI,
pre/postpaid, user‟s current location, billing
details, phone status – parameters. .
VLR is a temporary database that is
updated whenever a new MS enters its area
by roaming. The information is obtained
from the corresponding HLR. i.e., VLR
supports roaming functions for users outside
the coverage area of their own HLR
HLR stores important information that is
specific to each subscriber in a database.
It is essentially a temporary database that is
updated whenever a new MS enters its area
by roaming.
24. List the services offered by GPRS[CO3 – L1]
Point-to-Point (PTP) service – The PTP service is between two users and can either
be connectionless or connection-oriented.
Point-to-Multipoint (PTM) service – The PTM is a data transfer service from one
user to multiple users. There are two types of PTM services namely Multicast PTM
(broadcast in certain area) and Group call PTM (addressed to a group of users).
25. Expand GSN, GGSN, and PDN. [CO3 – L1]
 GSN – GPRS support node (GSN)
 GGSN – Gateway GPRS support node (GGSN)

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 PDN – Packet Data Network (PDN)
26. Identify the similarities between GSM network and UMTS network[CO3 – L1]
UMTS systems are compatible with GSM networks. UMTS networks can easily work
with any existing GSM/GPRS network. The UMTS systems use different frequency
bands, so the BTSs do not interfere with each other.
27. Identify the dissimilarities between GSM network and UMTS network[CO3 – L1]
 Higher speech quality: In addition to speech traffic, UMTS supports the advanced
data and information services and can be called a true multimedia network.
 Higher data rate
 Virtual home environment (VHE): A user roaming from his network to other UMTS
networks will not feel any discontinuity or service difference, thus giving a “feeling”
of being in the home network. In contrast in 2G network, a user is registered to a
visitor location and is also charged a roaming overhead.
28. Name the components of UMTS network architecture. (or) [CO3 – L1]
What are the main elements of UMTS? (May/June 2016)
 User Equipment (UE)
 Radio Network Subsystem (RNS)
 Core Network
29. Differentiate soft hand off from hard hand off. (Nov/Dec 2011) [CO3 – L3]
Hard Hand off Soft hand off
With hard handoff, the link to the prior
base station is terminated before or as the
user is transferred to the new cell‟s base
station. That is to say that the mobile is
linked to no more than one base station at a
given time.
With soft handoff, each mobile user is
connected to two or more base stations at a
time.
Initiation of the handoff may begin when
the signal strength at the mobile received
from base station 2 is greater than that of
base station 1.
The base station with the highest relative
strength seen from the mobile is given the
control of the mobile user‟s call. Also,
because a user in soft handoff is connected
to several adjacent base stations,
probability of a lost call is reduced.
30. State the pros and cons of GSM. (Nov/Dec 2011) [CO3 – L2]
Pros:
 GSM is very popular, with over 450,000,000 subscribers as of today
 This network supports international roaming, hence is the popular choice among
users
 GSM offers a stable network with a host of robust functionalities
 Global market meant roaming was easy & standard
 SIM card made it easier for consumers to upgrade & facilitated second hand
market; driving costs down & market volumes up.
Cons:
The per-unit charge on roaming calls is higher in GSM than in CDMA.
• Calls made through GSM mobiles can be tampered.

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• If the SIM gets lost, one can lose all the data, if the same is not saved in the phone.
CDMA is a form of spread spectrum, which clearly means that data is sent in small
pieces over a number of the discrete frequencies available for use at any time in the
specified range. Unlike GSM, it does not use the SIM card, rather gives a specific
serial number to the handsets.
31. What are the types of handover in GSM? (Nov/Dec 2012) [CO3 – L1]
 Intra cell Handover
 Inter cell Intra BSC Handover
 Inter BSC Intra MSC handover
 Inter MSC Handover
32. List the standards similar to GSM. (May/June 2012) [CO3 – L1]
 Enhanced Data Rates for GSM Evolution (EDGE)
 General Packet Radio Service (GPRS)
 Universal Mobile Telecommunications system (UMTS)
33. What is mobile number portability? (May/June 2013) [CO3 – L1]
MNP or mobile number portability, allows you to switch your mobile phone operator
from one mobile phone network provider to another mobile phone provider and keep your
existing mobile phone number
34. What is handoff? List out its characteristics (May/June 2013) [CO3 – L1]
In a cellular telephone network, handoff is the transition for any given user of signal
transmission from one base station to a geographically adjacent base station as the user
moves around. Each time a mobile or portable cellular subscriber passes from one cell
into another, the network automatically switches coverage responsibility from one base
station to another. Each base-station transition, as well as the switching processor
sequence itself, is called handoff. In a properly functioning network, handoff occurs
smoothly, without gaps in communications and without confusion about which base
station should be dealing with the subscriber.
35. What is Equipment Identity Register? (Nov/Dec 2013) [CO3 – L1]
The EIR is a database for all IMEIs, i.e., it stores all device identifications registered for
this network. As MSs are mobile, they can be easily stolen. With a valid SIM, anyone
could use the stolen MS. The EIR has a blacklist of stolen (or locked) devices. In theory
an MS is useless as soon as the owner has reported a theft. Unfortunately, the blacklists of
different providers are not usually synchronized and the illegal use of a device in another
operator‟s network is possible (the reader may speculate as to why this is the case). The
EIR also contains a list of valid IMEIs (white list), and a list of malfunctioning devices
(gray list).
36. What are the reasons for handover? (Nov/Dec 2013) [CO3 – L1]
 Signal strength/power
 speed of the device/mobile
 weaker signal from serving Base station and strong signals from neighbour base
stations
 Bit Error Rate

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 Interference from adjacent channels
37. How can wired infrastructure of GSM decide hand over operation? (May/June
2014) [CO3 – L2]
There are mainly two reasons for this kind of handover. The mobile station moves out of
the range station or the antenna of BTS respectively. Secondly the wire infrastructure the
MSC or the BSC may decide that the traffic in one cell is too high and move some to
other cells with lower load. These are the main reasons that initiate different kinds of
handover.
38. Give the block diagram of subscriber authentication in GSM architecture.
(May/June 2014) [CO3 – L2]
39. What is the functionality of GGSN? (May/June 2014) [CO3 – L1]
GGSN is Gateway GPRS Support Node. It is the inter-working unit between the GPRS
network and external packet data networks. The GGSN is connected to external networks
via the Gi interface and transfers packets to the SGSN via an IP based GPRS backbone
network.
40. What is the frequency range of uplink and downlink in GSM network? [CO3 – L1]
The frequency range of uplink in GSM network is 890-960 MHz
The frequency range of downlink in GSM network is 935-960 MHz
41. What is meant by beacon? [CO3 – L1]
A beacon contains a timestamp and other management information used for power
management and roaming. e.g., identification of the base station subsystem (BSS)
42. What are the advantages of GPRS? (Nov/Dec 2012) [CO3 – L1]
The advantages of GPRS are,
 Improves utilization of the radio resources
 Multiple users can share one physical channel
 Volume-based billing
 Higher transfer rates Max 171.2Kbits/sec
 Shorter access times
 Simplifies the access to packet data networks.

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43. What is the use of GSM in mobile telecommunication? Nov/Dec 2011&12 May/June
12[CO3 – L1]
This system was soon named the Global System for Mobile communications (GSM),
The primary goal of GSM was to provide a mobile phone system that allows users to roam
and provides voice services compatible to ISDN and other PSTN systems
44. What is meant by SMS and EMS? [CO3 – L1]
 A useful service for very simple message transfer is the short message
service(SMS), which offers transmission of messages of up to 160 characters
 The successor of SMS, the Enhanced Message Service (EMS), offers a larger
message size (e.g., 760 characters, concatenating several SMs), formatted text,
and the transmission of animated pictures.
45. List the 3 important features of GSM Security. May/June 2016[CO3 – L1]
1. Authentication – used to protect the network against unauthorized use.
2. Confidentiality – Data on the radio path is encrypted between the Mobile Equipment
(ME) and the BTS which protects user traffic and sensitive signalling data against
eavesdropping.
3. Anonymity – Anonymity is achieved by allocating Temporary Mobile Subscriber
Identity (TMSI) instead of permanent identities to protect against tracking a user‟s
location and obtaining information about a user‟s call log.
46. What is meant by GPRS? (May/June 12)[CO3 – L1]
GPRS (General Packet Radio Services) is a packet-oriented mobile data service on the
GSM of 3G and 2G cellular communication systems. It is a non-voice, high-speed and useful
packet-switching technology for GSM networks.
47. What ways is GPRS better than GSM? [CO3 – L1]
GSM uses a billing system based on the time of connection whereas GPRS uses a
billing system based on the amount of transmitted data.
48. What is the function of GGSN? (May/June 2014) [CO3 – L1]
• The gateway GPRS support node (GGSN) is the interworking unit between the GPRS
network and external packet data networks (PDN). This node contains routing
information or GPRS users, performs address conversion, and tunnels data to a user
via encapsulation.
• The GGSN is connected to external networks (e.g., IP or X.25) via the Gi interface
and transfers packets to the SGSN via an IP-based GPRS backbone network (Gn
interface).
49. What are the main elements of UMTS? (May/June 2016) [CO3 – L1]

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• User Equipment / Mobile Station (MS): is the name by which a cell phone is referred
to Radio Network Subsystem (RNS): Equivalent of Base Station Subsystem (BSS) in
GSM.
• It provides and manages the wireless interface for the overall network.
• Core Network (CN): Equivalent of the Network Switching Subsystem (NSS) in GSM.
50. What is the use of emergency number? [CO3 – L1]
Service offered by GSM is the emergency number. This service is mandatory for all
providers and free of charge. This connection also has the highest priority, possibly
pre-empting other connections, and will automatically be set up with the closest
emergency center
51. Difference between 1g,2g,3g,4g,5g? [CO3 – L2] [CO3 – L3]
52. Write about the supplementary services in GSM? Nov/Dec 2016[CO3 – L2]
Supplementary services
GSM provides certain supplementary services such as user identification, call
redirection, and forwarding of ongoing calls. In addition, standard ISDN features such as
„close user groups and „multiparty‟ communication are available.

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UNIT III
MOBILE NETWORK LAYER
1. Define Mobile IP. [CO2 – L2]
Mobile IP is a standard protocol created by extending Internet Protocol (IP) to enable
users to keep the same IP address while travelling from one network to a different
network.
Mobile IP = Mobility + Internet Protocol (IP)
2. Define Tunneling. [CO2 – L2]
Tunneling is the process of delivering the packet sent by the Home Agent(HA) to foreign
agent(COA) and from COA to the mobile node via tunnel. Tunneling has two primary
functions:
Encapsulation of the data packet to reach the tunnel endpoint,
Decapsulation when the packet is delivered at that endpoint.
3. What is encapsulation in Mobile IP? [CO2 – L2]
Encapsulation refers to arranging a packet header and data and putting it into the data
part of a new packet. Thus the encapsulated packet will contain the new destination
address as “Address of COA” and the new source address as “Address of HA”.
4. What should the value of TTL Filed in the IP packet of agent advertisement? Why?
May/June 2014[CO2 – L2]
The TTL field of the IP packet is set to 1 for all advertisements to avoid forwarding
them. The IP destination address according to standard router advertisements can be
either set to 224.0.0.1, which is the multicast address for all systems on a link or to the
broadcast address
255.255.255.255.
5. What are the possible locations for care of address? Nov/Dec 2013[CO2 – L1]
The COA defines the current location of the MN from an IP point of view. All IP packets
sent to the MN are delivered to the COA, not directly to the IP address of the MN. Packet
delivery toward the MN is done using a tunnel, as explained later. To be more precise,
the COA marks the tunnel endpoint, i.e., the address where packets exit the tunnel There
are two different possibilities for the location of the COA:
 Foreign agent COA
 Co-located COA
6. What are the possible locations of Tunnel end point of Mobile IP? May/June
2014[CO2 – L1]
A tunnel establishes a virtual pipe for data packets between a tunnel entry and a tunnel
endpoint. Packets entering a tunnel are forwarded inside the tunnel and leave the tunnel
unchanged.
Tunneling, i.e., sending a packet through a tunnel is achieved by using encapsulation.
The possible locations of Tunnel end point are
 Home Agent (HA)
 Foreign Agent (FA)
7. Differentiate traditional IP from mobile IP[CO2 – L3]

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Traditional IP Mobile IP
Traditional IP doesn‟t support user
mobility.
Mobile IP allows mobile computers to
stay connected to the internet
regardless of their location and
without changing the IP address.
In Traditional IP addressing scheme,
when a host moves to a different
location, it may move to another
network changing its IP address.
Mobile IP was created by extending IP to
enable users to keep the same IP
address while travelling to a different
network.
8. State the limitations of IPv4[CO2 – L2]
 IPv4 would not be able to support enormous number of users that are expected to use
internet in couple of years.
 IPv4 doesn‟t distinguish among the different applications, and treats all applications
equally. However, the quality of service (QoS) requirement of different application may
be different.
9. Define Home Address and Home Network [CO2 – L1]
 Home address of a mobile device is the IP address assigned to the device within its
home network. The IP address on the current network is known as home address.
 The home network of a mobile device is the network within which the device receives
its identifying IP address (home address). Within the home address, there is no need
of mobile IP.
10. Define Foreign Agent and Foreign Network[CO2 – L1]
 The foreign agent is a router in a foreign network that functions as the point of
attachment for a mobile node when it roams to the foreign network.
 The foreign network is the current subnet to which the mobile node is visiting. In
other words, a foreign network is the network in which a mobile node is operating when
away from its home network.
11. State Mobile Node[CO2 – L2]
A mobile node is hand-held equipment with roaming capabilities. It can be a cell phone, PDS,
laptop, etc.
12. Write short notes on the following: [CO2 – L2]
(a) Correspondent Node
The home agent is a router on the home network serving as the anchor point for
communication with the mobile node. It tunnels packets from a device on the
internet, called a correspondent node (CN) to the roaming mobile node.
(b) Care-of-Address
It is the address that is used to identify the present location of a foreign agent. The
packets sent to the MN are delivered to COA. COA can be of two types,
i) Foreign agent COA
ii) Co-located COA
13. What are the disadvantages of mobile IP? [CO2 – L1]
 There is a routing inefficiency problem caused by the “triangle routing” formed by the
home agent, correspondent host, and the foreign agent.
 Security risks are the most important problem faced by Mobile IP. Besides the
traditional security risks with IP, one has to worry about faked care‐of addresses.

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14. Write short notes on the following: [CO2 – L2]
(a) Agent Discovery
During call establishment it is necessary for a mobile node to determine its foreign agent.
This task is referred to as agent discovery.
(b) Tunnelling and Encapsulation
Tunnelling establishes a virtual pipe for the packets available between a tunnel entry and
an endpoint. Tunnelling is a process of sending a packet via a tunnel and it is
achieved by a mechanism called encapsulation. Encapsulation refers to arranging a
packet header and data in the data part of the new packet.
15. State Decapsulation[CO2 – L2]
Disassembling the data part of an encapsulated packet is called Decapsulation.
16. What do you mean by agent solicitation? [CO2 – L1]
The agent solicitation messages are sent by a mobile node (MN) to search for a foreign agent
(FA).
17. State Encapsulation in the context of Mobile IP. (Or) [CO2 – L2]
What is encapsulation in mobile IP? (May/June 2016)
When a home agent receives a packet addressed to a mobile host, it forwards the packet to the
care-of-address using IP-within-IP (encapsulation).
18. What do you mean by the term binding of a mobile node? [CO2 – L1]
The association of the home address with a care-of-address is called binding.
19. Match the packet loss in wired network to the wireless network. [CO2 – L2]
Packet loss in wired networks Packet loss in wireless networks
packet losses primarily occur on account
of congestions encountered in the
transmission path
Packet losses can occur due to mobility
and channel errors. Packet may also
get lost during handoff.
Bit errors are rare Vulnerable to noise and noise can cause
intermittent bit errors. Intermittent
disconnections due to fading and
obstructions that may be encountered
by the mobile host.
19. What is DHCP? (May/June 2016) [CO2 – L1]
DHCP stands for Dynamic Host Configuration Protocol. DHCP is an extension to the
BOOTP and compatible with it. The importance of DHCP in a mobile computing
environment is that it provides temporary IP addresses whenever a host moves from one
network to another network.
20. What are the possible locations of tunnel end point in Mobile IP? (May/June 2014)
(or)
What are the possible locations for care of address? (Nov/Dec 2013) [CO2 – L1]
A tunnel establishes a virtual pipe for data packets between a tunnel entry and a tunnel
endpoint.

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A foreign agent provides a foreign agent care-of address through its agent advertisement
messages. In this case, the care-of address is an IP address of the foreign agent. The
foreign agent is the end point of the tunnel and, on receiving tunnelled datagrams, de-
encapsulates them and delivers the inner datagram to the mobile node. In this mode,
many mobile nodes can share the same care-of address. This sharing reduces demands on
the IPV4 address space and can also save bandwidth, because the forwarded packets,
from the foreign agent to the mobile node, are not encapsulated. Saving bandwidth is
important on wireless links.
A mobile node acquires a co-located care-of address as a local IP address through some
external means, which the mobile node then associates with one of its own network
interfaces. The address might be dynamically acquired as a temporary address by the
mobile node as a long-term address for its use only while visiting some foreign network.
When using a co-located care-of address, the mobile node serves as the end point of the
tunnel and performs de-encapsulation of the datagrams tunnelled to it.
21. What should be the value of TTL field in the IP packet of agent advertisement?
Why? (May/June 2014) [CO2 – L1]
The TTL field of the IP packet is set to 1 for all advertisements to avoid forwarding
them.
22. What is triangular routing? (Nov/Dec 2013) [CO2 – L1]
With the basic mobile IP protocol all packets to the Mobile Node (MN) have to go
through the Home Agent (HA). This can cause unnecessary overheads for the network
between Corresponding Node (CN) and Home Agent (HA), but also between HA and
Care-of-Address (COA), depending on the current location of the MN (that is even when
MN is closer to CN). The inefficient behaviour of a non-optimized mobile IP is called
triangular routing.
23. Differentiate types of Care-of address. (Nov/Dec 2012) [CO2 – L3]
The Care-of address can be of two types,
Foreign agent COA: The care-of address is an IP address of the foreign agent.
Co-located COA: A mobile node acquires a co-locate care-of address as a local IP
address through some external means, which the mobile node then associates with one of
its own network interfaces. The address might be dynamically acquired as a temporary
address by the mobile node, such as through DHCP.
24. What is selective retransmission? (Nov/Dec 2012) [CO2 – L1]
TCP acknowledges are cumulative i.e., they acknowledge in-order receipt of packets up
to a certain packet. If a single packet is lost, the sender has to retransmit everything
starting from the lost packet. This obviously wastes bandwidth. Using RFC 2018, TCP
can indirectly request a selective retransmission of packets. The sender can now
determine precisely which packet is needed and can retransmit it. This is called as
Selective transmission.
25 Define ad-hoc network. (EC2050 Nov/Dec 2014) [CO4 – L1]
An ad hoc network is a continuously self-configuring, infrastructure-less network of
mobile devices connected without wires.

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26 Why can’t the traditional routing strategies be deployed in a MANET straightaway?
[CO4 – L2]
In a MANET, the topology of the network and consequently the routes between
different devices change dynamically as nodes move away or fail. This is in contrast to
any wired network. With the continual topology changes and limited battery power of the
nodes, traditional routing strategies of wired network can‟t be deployed in MANET
straightaway.
27 List the characteristics of MANETs (EC2050 May 2012, IT6601 May/June 2016)
[CO4 – L1]
 Lack of fixed infrastructure
 Dynamic topologies
 Bandwidth constrained, variable capacity links
 Energy constrained operation
 Distributed peer-to-peer mode of operation
 Multi-hop routing
28 How is an ad-hoc network set up without the infrastructure support? [CO4 – L2]
A mobile device that wants to communicate can forward its packets to its neighbours
and so on until the destination is reached. This essentially forms a simple ad-hoc network
without any form of fixed networking infrastructures.
29 What do you mean by dynamic topology in a MANET? [CO4 – L1]
Since the devices in a MANET are allowed to move arbitrarily, the network topology
can change unpredictably. The rate of topology changes depends on the speed of
movement of the mobile devices. This is known as dynamic topology in a MANET.
30 List four applications of mobile ad-hoc network. (EC2050 Nov/Dec 2014) [CO4 – L1]
 Communication among portable computers
 Environmental monitoring
 Military
 Emergency applications
31 What are the important design constraints of MANET? [CO4 – L1]
 Network size and node density
 Connectivity
 Network topology
 User traffic
 Operational environment
 Energy constraint

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32 What is the difference between reactive and proactive routing in MANETs? (EC2050
May 2012, Nov/Dec 2014) [CO4 – L3]
Proactive protocols Reactive protocols
Proactive routing protocol is also known
as a table-driven routing protocol.
A reactive routing protocol is also
known as an on-demand routing
protocol.
Each node in a routing table maintains
information about the routes to every
other node in the network.
Nodes don‟t maintain up-to-date routes
to different destinations, and new routes
are discovered only when required.
The tables are periodically updated in
the face of random network topology
changes.
When a node doesn‟t have knowledge
about any route to a specific destination,
it uses
E.g. Destination Sequenced Distance
Vector (DSDV) protocol.
E.g. Dynamic Source Routing (DSR)
protocol.
Ad-hoc on demand distance vector
routing (AODV)
33 What is a hybrid routing protocol? Why is it needed? (EC2050 May 2012) [CO4 –
L1]
Hybrid routing protocols have the characteristics of both proactive and reactive
protocols. These protocols combine the good features of both the protocols. The hybrid
routing protocols are designed to achieve increased scalability by allowing nodes with
close proximity to work together to form some sort of a backbone to reduce the route
discovery overheads.
34 How are the security threats in MANETs different from a wired network? [CO4 –
L2]
In a wired network or in an infrastructure-based wireless network, an intruder is
usually a host that is outside the network and therefore could be controlled through a
firewall and subjected to access control and authentication. In a MANET, an intruder is
part of the network, and therefore much more difficult to detect and isolate. The
distinction between nodes that are internal or external to a network becomes meaningless,
making it difficult to deploy firewalls or monitor the incoming traffic.
35 State Dynamic Source Routing. [CO4 – L2]
Dynamic source routing protocol (DSR) is an on-demand protocol designed to restrict
the bandwidth consumed by control packets in ad hoc wireless networks by eliminating
the periodic table-update messages required in the table-driven approach. The major
difference between this and the other on-demand routing protocols is that it is beacon-less
and hence does not require periodic hello packet (beacon) transmissions, which are used
by a node to inform its neighbours of its presence. The basic approach of this protocol
(and all other on-demand routing protocols) during the route construction phase is to
establish a route by flooding route request packets in the network. The destination node,

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on receiving a route request packet, responds by sending a route reply packet back to the
source, which carries the route traversed by the route request packet received.
36 List some routing attacks on the application layer of a MANET. [CO4 – L1]
 Denial of Service attack
 Black hole attack
 Replay attack
37 Compare MANET vs. VANET. (IT6601 May/June 2016) [CO4 – L3]
MANET VANET
It is a collection of nodes(vehicles) that
communicate with each other over
bandwidth constrained wireless links
with certain road side infrastructure or
base station
It is a collection nodes that
communicate with each other over
bandwidth constrained wireless links
without any infrastructure support
Regular node movement pattern Random node movement pattern
High mobility Low mobility
Bandwidth- 1000 kbps Bandwidth- 100 kbps
38 Mention the important differences between a mobile ad-hoc network and a cell
phone network. [CO4 – L2]
Cell phone network Mobile ad-hoc network
Infrastructure based network Infrastructure less network
Fixed, pre-located cell sites and
base stations
No base station and rapid
deployment
Static network topology Highly dynamic network topologies
Relatively caring environment and
stable connectivity
Highly dynamic network topologies
High setup costs Cost-effective
Large setup time Less setup time
39 Write short notes on the characteristics of a secure ad-hoc network. [CO4 – L1]
A secure ad-hoc network should have the following characteristics:
Availability: It should be able to survive denial-of-service (DoS) attacks.
Confidentiality: It should protect confidentiality of information by preventing its access
by unauthorized users.
Integrity: It should guarantee that no transferred message has been tampered with.
Authentication: It should help a node to obtain guarantee about the true identity of a peer
node.
Non-repudiation: It should ensure that a node having sent a message, cannot deny it.

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40 Differentiate Passive attacks and active attacks[CO4 – L3]
Passive Attacks Active Attacks
Passive attacks target to monitor and
steal the data exchanged in the network,
without disrupting the network.
Active attacks are destructive and
disturbs the normal functionality of the
network.
It becomes very difficult to identify
these attacks as they don‟t have any
perceivable symptoms
The damages caused by these attacks
results in loss of data, resources etc.
These attacks can be reduced by suitable
encryption techniques
Maintenance of trust rating of various
nodes is one of the promising
techniques.
E.g. Snooping, eavesdropping, traffic
analysis, monitoring
Wormhole, black hole, grey hole,
resource consumption, routing attacks.
41 Enlist the attacks at different layers of a MANET protocol stack[CO4 – L1]
Layer Attacks
Application Layer Malicious code, repudiation, data corruption
Transport Layer Session hijacking, SYN flooding
Network Layer Wormhole, black hole, fabrication attack
Data Link Layer Resource consumption
Physical Layer Traffic analysis, monitoring, disruption, jamming,
interceptions, eavesdropping
Multilayer Denial-of-Service(DoS), impersonation, replay
42 State some of the common traffic types[CO4 – L1]
 Bursty Traffic
 Large packets sent periodically
 Combination of the above two types of traffic
43 Define Network size and Node density[CO4 – L1]
Network size refers to the geographical coverage area of the network and network
density refers to the number of nodes present per unit geographical area.
44 Give examples for mobile ad hoc networks (May/June 2013) [CO4 – L1]
• Vehicular Ad Hoc network (VANET),
• Smart phone ad hoc networks (SPAN) .
45 Differentiate wired networks and ad hoc wireless networks based on
routing.(Nov/Dec 2013) [CO4 – L3]
Wired Network based routing Ad hoc wireless networks based on routing
No significant change in the topology or
power constraint
Continual change in topology and limited
battery power of nodes.
Routing is a relatively easy task because the
routes to nodes can be uniquely and
efficiently identified based on the subnet
structure encoded in IP.
In a MANET, the nodes making up a route
may themselves move or shut down due to
low battery energy. It is therefore necessary
to find a new route each time a node needs to
transmit a message, making an expensive and
difficult task.

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46. Compare Link State Distance Vector Routing and[CO4 – L3]
Link State Routing Distance Vector Routing
It can be used in larger networks It can be used in smaller networks
It has unlimited number of hops It has limited number of hops
Convergence time is low Convergence time is high
Advertises only new changes Periodically advertise updates
Only advertise the updates and flood
the advertisement
Advertises the entire routing tables to
all its neighbors
47 Give the classification of MANET routing protocols[CO4 – L1]
48 What is meant by VANET? [CO4 – L1]
A Vehicular Ad hoc Network (VANET) is a special type of MANET in which moving
automobiles form the nodes of the network. i.e., vehicles are connected to each other through
an ad hoc formation that forms a wireless network.
49. Mention the goals of VANET. [CO4 – L1]
• Improve traffic safety and comfort of driving
• Minimize accidents, traffic intensity, locating vehicles
• Up-to-date traffic information
• Intersection collision warning
• Weather information
50. What are the characteristics of VANETs? [CO4 – L1]
1) High mobility of nodes
2) Rapidly changing network topology
3) Unbounded network size
4) Higher computational capacity
5) Time-sensitive data exchange
6) Potential support from infrastructure
7) Abundant Resources
8) Partitioned Network
9) Unlimited Transmission Power

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51. List out the applications of VANETs. [CO4 – L1]
 Safety oriented
 Real-time traffic
 Cooperative message transfer
 Post-crash notification
 Road hazard control notification
 Traffic vigilance
 Commercial oriented
 remote vehicle personalization
52. What is multicasting? (Nov/Dec 2016) [CO4-L1] [CO4 – L1]
Multicast is group communication where information is addressed to a group of destination
computers simultaneously. Otherwise a message is sent to a selected subset of the network
nodes

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UNIT IV MOBILE TRANSPORT AND APPLICATION LAYER
1 Differentiate snoopy TCP and mobile TCP. Nov/Dec 2014[CO2 – L2]
 The Snoop protocol is a TCP-aware link layer protocol designed to improve the
performance of TCP over networks of wired and single-hop wireless links. The
main problem with TCP performance in networks that have both wired and
wireless links is that packet losses that occur because of bit-errors are mistaken
by the TCP sender as being due to network congestion, causing it to drop its
transmission window and often time out, resulting in degraded throughput.
 In wireless systems, WTCP is placed on a base station or intermediate gateway
between a source host and a mobile (wireless) host. The base station is a wireless
transmitter and receiver for the mobile host, and acts as a gateway to the internet
for the host.
2 Define time out freezing. May/June 12 and May/June 2013 Nov/Dec 2014[CO2 – L1]
The MAC layer can inform the TCP layer of an upcoming loss of connection or that the
current interruption is not caused by congestion. TCP can now stop sending and „freezes‟
the current state of its congestion window and further timers
3 Define Selective retransmission. Nov / Dec 2012[CO2 – L1]
If a single packet is lost, the sender has to retransmit everything starting from the lost
packet (go-back-n retransmission). This obviously wastes bandwidth, not just in the case
of a mobile network, but for any network (particularly those with a high path capacity,
i.e., bandwidth delay- product
The advantage of this approach is obvious: a sender retransmits only the lost packets
4 Define fast retransmit and fast recovery. [CO2 – L1]
 The mechanisms of fast recovery/fast retransmit a host can use after receiving
duplicate acknowledgements, thus concluding a packet loss without
congestion.
 As soon as the mobile host registers at a new foreign agent using mobile IP, it
starts sending duplicated
5 State DNS. [CO2 – L2]
DNS stands for Domain Name System. It is a software service available on the Internet that is
responsible for translating domain names into IP addresses.
6 State IGMP[CO2 – L2]
IGMP stands for Internet Group Management Protocol. The IGMP protocol is used by hosts
to exchange information with their local routers to set up multicast groups.
7 What is slow start in TCP operation? [CO2 – L1]
The slow start mechanism is used when a TCP session is started. Instead of starting
transmission at a fixed transmission window size, the transmission is started at the lowest
window size, and then doubled after each successful transmission. Thus the doubling of
the window size occurs at every round trip time (RTT).

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8 What problems would occur if the traditional TCP is used in mobile wireless
environments? [CO2 – L1]
The main differences between wired network and wireless networks are much lower
bandwidth, bandwidth fluctuations with time and also as a mobile host moves, higher
delay, intermittent disconnections, high bit error rate, and poor link reliability.
9 Why are the I-TCP acknowledgements and semantics not end-to-end? What are the
implications of this? [CO2 – L2]
I-TCP protocol segments the connection between the fixed host and the mobile host into
two different connections: the wired part and the wireless part. The base station
maintains two separate TCP connections: one over the fixed network (to Fixed Host FH)
and the other over the wireless link (to mobile host MH). Due to this, I-TCP doesn‟t
maintain the semantics of TCP as the FH gets the acknowledgement before the packet is
delivered at MH and I-TCP doesn‟t maintain the end-to-end semantics of TCP and
assumes that the application layer would ensure reliability.
10 How are handoffs handled in snooping TCP? [CO2 – L2]
Snooping TCP hides the duplicate acknowledgement for the lost TCP segment and re-
sends the packet locally if it has buffered. When MH moves from its current Base station
(BS) to a new BS, higher overheads are incurred though the packet buffered at the
current BS need not be transferred to the new BS.
11 Why do congestions occur in a network? [CO2 – L2]
When many packets are transmitted to a single receiver and the rate with which these
packets are transmitted is higher than the processing rate of the destination host or an
intermediate router, the buffers of the router get filled quickly. This results in dropping
packets at the affected router or the destination known as congestion.
12 Define Freeze TCP. (or) What is time-out freezing? (May/June 2013) [CO2 – L1]
The basic idea in this scheme is to “freeze” the TCP senders‟ streams, little before a
disconnection to occur. This is done by artificially sending a “Zero Windows Advertisement”
informing the sender that the receiver cannot receive data at the moment. When the sender
resumes its connectivity, the receiver can unfreeze the sender by sending the value of its
actual receive window.
13 Why does I-TCP isolate problems on the wireless link? (May/June 2013) [CO2 – L1]
Due to strict partitioning between wired and wireless connections, transmission errors on
the wireless link, i.e., lost packets cannot propagate into the fixed networks. Without
partitioning, retransmission of lost packets would take place between mobile host and
corresponding host across the whole network.
14 Write the merits of transaction oriented TCP. (May/June 2012) [CO2 – L2]

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The merits of transaction oriented TCP are,
i. Transaction oriented TCP (T/TCP) can combine packets for connection
establishment and connection release with user data packets. This can reduce the
number of packets down to two instead of seven.
ii. Reduction in the overhead for connection setup and connection release which
standard TCP had.
15 How do you classify TCPs? (May/June 2012) [CO2 – L2]
The various kind of enhancements to TCP are realized for mobility and they are as,
 Indirect TCP
 Snooping TCP
 M-TCP
 Fast retransmit/fast recovery
 Transmission/time-out freezing
 Selective transmission
 Transaction-oriented TCP
16 What are the difference between TCP and UDP? [CO2 – L2]
TCP UDP
Connection oriented protocol Connection less protocol
TCP provides extensive error checking
mechanisms like flow control and
acknowledgment of data.
UDP has only the basic error checking
mechanism using checksums
TCP is reliable as it guarantees delivery of
data to the destination router.
The delivery of data to the destination cannot
be guaranteed in UDP
Retransmission of lost packets is possible in
TCP
Retransmission of lost packets is not possible
in UDP
TCP header size is 20 bytes UDP Header size is 8 bytes
TCP is used by HTTP, HTTPs, FTP, SMTP
and Telnet
UDP is used by DNS, DHCP, TFTP, SNMP,
RIP, and VoIP.
17 Differentiate between TCP/IP and TCP/IP? [CO2 – L2]
TCP/IP TCP/IP
OSI provides layer functioning and
also defines functions of all the layers
TCP/IP model is more based on protocolsand
protocols are not flexible with other layers
In OSI model the transport layer
guarantees the delivery of packets
In TCP/IP model the transport layer does
not guarantees delivery of packets
Follows horizontal approach Follows vertical approach
OSI model has a separate presentation
layer
TCP/IP does not have a separate
OSI is a general model It cannot be used in any other

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18 State whether standard TCP alone support mobile users or wireless links and why?
[CO2 – L1]
No, standard TCP alone cannot support wireless links because wireless links have
much higher error rates compared to wired links. The link layer may try to correct errors
which results in higher delays and mobility (Handover between access points) may result in
packet loss. In both cases standard TCP goes into slow start state.
18 What is Wireless application protocol?
• The objectives of the WAP Forum and OMA are to bring diverse internet content
(e.g., web pages, push services) and other data services (e.g., stock quotes) to digital
cellular phones and other wireless, mobile terminals (e.g., PDAs, laptops )
19 What are the Advantages of WAP ?
• interoperable
• scalable
• efficient
• reliable
• secure
20 Draw the architecture of WAP.
21 What is Wireless datagram protocol ?
• The wireless datagram protocol (WDP) operates on top of many different bearer
services capable of carrying data. At the T-SAP WDP offers a consistent datagram
transport service independent of the underlying bearer.
• If the bearer already offers IP services, UDP is used as WDP. WDP offers more or less
the same services as UDP
22. List the WCMP error messages.
o destination unreachable (route, port, address unreachable),
o parameter problem (errors in the packet header),

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o message too big,
o reassembly failure,
o echo request/reply
23. What is WDP management entity ?
• An additional WDP management entity supports WDP and provides information
about changes in the environment, which may influence the correct operation of WDP.
• Important information is the
o current configuration of the device,
o currently available bearer services,
o Processing and memory resources etc.
24 What is Wireless transport layer security?
• A security service, the wireless transport layer security (WTLS) can be integrated
into the WAP architecture on top of WDP. WTLS can provide different levels of
security (for privacy, data integrity, and authentication) and has been optimized for
low bandwidth, high-delay bearer networks.
25. What is Wireless Transaction protocol?
– A transaction is defined as a request with its response, e.g. for a web page. WTP has
been designed to run on very thin clients, such as mobile phones.
– WTP offers several advantages to higher layers
– an improved reliability over datagram services
– improved efficiency over connection-oriented services
– Support for transaction-oriented services such as web browsing.
26. What is the function of WTP class 0 ?
Class 0 offers an unreliable transaction service without a result message. The transaction is
stateless and cannot be aborted.
27. What is the function of WTP class 1 ?
• Class 1 offers a reliable transaction service but without a result message. Again, the
initiator sends an invoke PDU after a TR-Invoke.req from a higher layer. This time,
class equals „1‟, and no user acknowledgement has been selected.
28 What are the functions of Function of WTP class 2 ?
• Class 2 transaction services provide the classic reliable request/response transaction
known from many client/server scenarios.
• Depending on user requirements, many different scenarios are possible for
initiator/responder interaction.
29 What is Wireless session protocol?
WSP provides a shared state between a client and a server to optimize content
transfer. WSP offers content exchange between cooperating clients and servers.
30 What are the features of Wireless session protocol?
 Session management:
 Capability negotiation:
 Content encoding:

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 WSP/B
31 What is the Function of WSP/B ?
WAP has specified the wireless session protocol/browsing (WSP/B) which comprises
protocols and services most suited for browsing-type applications.
32 What are the features of WSP/B adapted to web browsing?
 HTTP/1.1 functionality
 Exchange of session headers
 Push and pull data transfer
 Asynchronous requests
33. What is the function of WSP/B over WTP ?
WSP/B uses the three service classes of WTP. Class 0 is used for unconfirmed push,
session resume, and session management. Confirmed push uses class 1, method invocation,
session resume, and session management class 2.
34. what is Wireless application environment ?
Wireless application environment (WAE) is creating a general-purpose application
environment on existing technologies of the World Wide Web. This environment allows
service providers, software manufacturers, or hardware vendors to integrate their
applications.
35 List the WAE technologies
• HTML & JavaScript
• Wireless markup language (WML) & scripting language WMLscript.
36 What is Wireless markup language ?
The wireless markup language (WML) is based on the standard HTML known
from the www and on HDML. WML is specified as an XML document type. WML
follows a deck and card metaphor. A WML document is made up of multiple cards.
Cards can be grouped together into a deck.
37. What are the features of WML ?
– Text and images
– User interaction
– Navigation
– Context management
38 What are the capabilities of WMLScript ?
 Validity check of user input
 Access to device facilities

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 Local user interaction:
 It is standard programming languages such as functions, expressions, or while, if, for,
return etc. statements.
39. What is Wireless telephony application?
WTA is a collection of telephony specific extensions for call and feature control
mechanisms, data networks and voice networks that make phone calls and access all the
features of the mobile phone network .
40. Write public service libraries to make call in WML ?
• cc for WTACallControl,
• wp for WTAPublic.
• sc for setup call
• mc for make call
• Finally, one or more results could be returned. These results set variables in the user
agent context.
• Within a WML card, the URI for calling a certain number could be as follows:
41 Write a URI for calling a certain number and make a call in WML ?
wtai://wp/mc;07216086415
To make a call : WTAPublic.makeCall("07216086415");

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UNIT V
MOBILE PLATFORMS AND APPLICATIONS
1. What is meant by Mobile Operating System? [CO5 – L1]
A mobile operating system, also called a mobile OS, is software that is specifically
designed to run on mobile devices such as mobile phones, smartphones, PDAs, tablet
computers and other handheld devices. Much like the Linux or Windows operating system
controls your desktop or laptop computer, a mobile operating system is the software platform
on top of which other programs can run on mobile devices
2. List the applications for which the smart phones are used for. [CO5 – L1]
 Make video conference calls
 Send multimedia messages
 Take pictures
 Play media files
 Browse World Wide Web (WWW)
 Run remote applications etc.
3. Define Android SDK[CO5 – L1]
Android SDK is a software development kit that enables developers to create applications
for the Android platform. The Android SDK includes sample projects with source code,
development tools, an emulator, and required libraries to build Android applications.
4 What are Android and its advantages? [CO5-L1]
Android is a mobile operating system developed by Google, based on a the Linux
kernel and other open source software and designed primarily for touch screen mobile
devices such as smart phones, tablets and T.V
Advantages
 Open-source
 Platform-independent
 supports various technologies (camera, Bluetooth, wifi, speech, EDGE)
5 What Is the Google Android SDK? [CO5-L1]
The Android SDK provides the API libraries and developer tools necessary to build,
test, and debug apps for Android. It is composed of modular packages that can download
separately using the Android SDK Manager.
6 What is the Android Architecture? [CO5-L1]
Android Architecture is made up of 4 key components:
– Linux Kernel
– Libraries
– Android Framework
– Android Applications
7 Describe the Android Framework. [CO5-L1]

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The android framework is the set of API's that allow developers to develop apps for
android phones. It consists of tools for designing UIs like buttons, text fields, image panes,
and system tools like intents (for starting other apps/activities or opening files), phone
controls, media players etc.
8 What is the use of an activity Creator? [CO5-L1]
An activity Creator is the first step towards the creation of a new Android project. It is
made up of a shell script that will be used to create new file system structure necessary for
writing codes within the Android IDE.
9 Describe Activities. [CO5-L1]
Activity: An activity represents a single screen with a user interface. An activity provides the
window in which the app draws its UI like window or frame of Java
10 What are Intents? [CO5-L1]
Intent is a messaging object used to request an action from another app component.
Intents facilitate communication between components.
11 Differentiate Activities from Services. [CO5-L2]
Activity
An activity represents a single screen with a user interface. An activity provides the
window in which the app draws its UI
Service
Android service is a component that performs long run operations on the background
such as playing music, handle network transactions, interacting content providers etc. It
doesn't have any UI (user interface). The service runs in the background indefinitely even if
application is destroyed.
12 Define POS. (Nov/Dec 2016) [CO5-L1]
Point-of-Sale (PoS) usually means a checkout counter in a shop or supermarket. More
specifically, the point-of- sale often refers to the hardware and software used for handling
customer purchases at the checkout desks. An example of a PoS terminal is an electronic cash
register. Nowadays, the point-of-sale systems are used in almost every supermarket and are
used in many retail stores too.
13 What is the importance of Android in the mobile market? [CO5-L2]
Developers can write and register apps that will specifically run under the Android
environment. This means that every mobile device that is Android enabled will be able to
support and run these apps. With the growing popularity of Android mobile devices,
developers can take advantage of this trend by creating and uploading their apps on the
Android Market for distribution to anyone who wants to download it.

40 | P a g e
14 What do you think are some disadvantages of Android? [CO5-L2]
 Overheating is a common issue with Android phones, especially when playing games
loaded with heavy graphics.
 While android has many process running in the background this increase the usage of
RAM and decreasing Battery Performance
 Box of Malware Google play store
o Hackers are ahead of putting malware in Google play store. If you download
10 Applications a day, 6 will be malware.
 Android has large number of background process which runs in the background,
which eats so much mobile data
 This is another drawback of android OS, when you run large apps/Games most of the
time android shows error force close which is definitely annoying. However this is not
always the case with high end devices
15 What is ADB? [CO5-L1]
ADB is short for Android Debug Bridge. It allows developers the power to execute
remote shell commands. Its basic function is to allow and control communication towards
and from the emulator port.
16 What are the four essential states of an activity? [CO5-L1]
Active – if the activity is at the foreground
Paused – if the activity is at the background and still visible
Stopped – if the activity is not visible and therefore is hidden or obscured by
another activity
Destroyed – when the activity process is killed or completed terminated
17 Differentiate E-Commerce and M-Commerce.(Nov/Dec 2016) [CO5-L2]
E-commerce or electronic commerce, is the process of buying and selling goods,
products and services over electronic systems such as internet, telephone and e-mail.
M-Commerce or mobile commerce is process of buying and selling products and
services through wireless handheld devices such as cell phones or PDAs
18 What role does Dalvik play in Android development? [CO5-L1]
Dalvik serves as a virtual machine, and it is where every Android application runs.
Through Dalvik, a device is able to execute multiple virtual machines efficiently through
better memory management.
19 What is Radio Frequency Identification? [CO5-L1]
A Radio Frequency Identification (RFID) tag attached to a product, animal, or person for the
purpose of identification and tracking, makes use of radio waves. Some tags can be read from
several metres away and beyond the line of sight of the reader.
20 Do all mobile phones support the latest Android operating system? [CO5-L2]
Some Android-powered phone allows you to upgrade to the higher Android operating system
version. However, not all upgrades would allow you to get the latest version. It depends
largely on the capability and specs of the phone, whether it can support the newer features
available under the latest Android version.

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21 What is portable wifi hotspot? [CO5-L1]
Portable Wi-Fi Hotspot allows you to share your mobile internet connection to other wireless
device. For example, using your Android-powered phone as a Wi-Fi Hotspot, you can use
your laptop to connect to the Internet using that access point.
22 What is an action? [CO5-L1]
In Android development, an action is what the intent sender wants to do or expected to get as
a response. Most application functionality is based on the intended action.
23 What is the difference between a regular bitmap and a nine-patch image? [CO5-L1]
In general, a Nine-patch image allows resizing that can be used as background or other image
size requirements for the target device. The Nine-patch refers to the way you can resize the
image: 4 corners that are unscaled, 4 edges that are scaled in 1 axis, and the middle one that
can be scaled into both axes.
24 What language is supported by Android for application development? [CO5-L1]
The main language supported is Java programming language. Java is the most popular
language for app development, which makes it ideal even for new Android developers to
quickly learn to create and deploy applications in the Android environment.
Inventors of android: Andy Rubin, Rich Miner, Nick Sears
25 Features of Android OS? [CO5-L2]
Live wallpaper, Camera, Messaging, Bluetooth, WIFI, Web Browsing, Music, Alarm etc.
 Google now (voice assistant)
 NFC (Near Field Communication)
 Unlock your phone by your face
 Use your phone with joystick to enjoy gaming experience
 Connect your phone with LED TV via MHL or micro HDMI cable
 Screen Capture
 Multitasking Future (Task Switcher)
 Data Usages (Check and also set limit from device)
26 Tools Required for Developing Android Apps? [CO5-L1]
Tools:
 Java Development Kit (JDK)
 Android Development Tools (ADT) - Android Studio by Google
 Software Development Kit (SDK)
Languages:
 Java
 XML
27 Android application main components are? [CO5-L2]
Components Description
Activities They dictate the UI and handle the user interaction to the smart phone
screen
Services They handle background processing associated with an application
Broadcast
Receivers
They handle communication between Android OS and applications

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Content
Providers
They handle data and database management issues
28 What is AVD? [CO5-L1]
AVD Stand for Android Virtual Device (emulator), The Android SDK includes a mobile
device emulator - a virtual mobile device that runs on your computer.
29 Give four examples of Mobile OS? (May/June 2015) [CO5-L2]
 Android OS (Google Inc.)
 Bada (Samsung Electronics)
 BlackBerry OS (Research In Motion)
 iPhone OS / iOS (Apple)
 MeeGo OS (Nokia and Intel)
 Palm OS (Garnet OS)
 Symbian OS (Nokia)
 webOS (Palm/HP)
30 What is M-Commerce? (May/June 2015) [CO5-L1]
Mobile commerce, involves carrying out any activity related to buying and selling of
commodities, services, or information using the mobile hand-held devices. The popularity of
m-commerce can be traced to the convenience it offers both to the buyers and sellers.
An important issue in M-commerce is how payments can be made securely and
rapidly as soon as a buyer decides to make a purchase.
The use of computers and networking in trade related transactions has been limited to
automatic teller machines (ATMs), banking networks, debit and credit card systems,
electronic money and electronic bill payment systems (E-payment).
31. Differentiate explicit intent and implicit intent[CO5 – L3]
 Explicit intents specify which application will satisfy the intent, by supplying either
the target app's package name or a fully-qualified component class name. You'll
typically use an explicit intent to start a component in your own app, because you
know the class name of the activity or service you want to start.
 For example, you might start a new activity within your app in response to a user
action, or start a service to download a file in the background.
 Implicit intents do not name a specific component, but instead declare a general
action to perform, which allows a component from another app to handle it.
 For example, if you want to show the user a location on a map, you can use an
implicit intent to request that another capable app show a specified location on a map.
32. What are the advantages and disadvantages of Apple IOS? [CO5 – L1]
Advantages
 Excellent UI
 Larger number of applications
 availability
 Apple validates applications

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 Consistent UI across devices
 Frequent free OS updates
Disadvantages
 Closed architecture
 Limited number of devices to choose from – all from apple
 No multi-tasking for applications
 Applications must be approved by Apple before being made available via the
Marketplace
 Can‟t be unlocked
33. What are the advantages and disadvantages of Windows Phone OS? [CO5 – L1]
Advantages
 Built in support for Windows Office documents
 Multi-tasking
 Phones available form most service providers
 Excellent development tools, with free versions available to students
 Updates available directly from Microsoft
Advantages
 Closed architecture
 Small number of applications available
 Browser is a mix of IE7 and IE8 (a bit dated)
 Applications must be approved by Microsoft before being
34. What is meant by M-Payment (Mobile Payment)? [CO5 – L1]
A Mobile Payment (m-payment) may be defined as initiation, authorization and
confirmation of a financial transaction using a mobile devices like mobile phones, PDAs and
other devices that connects to a mobile network for making payments
35. What are the different Mobile Payment System models? [CO5 – L1]
There are three different models available for mobile payment solutions on the basis of
payment:
 Bank account based
 Credit card based
 Micro Payment
36. List out the various technologies used for M-Payment systems.
a) SMS (Short Message Service)
b) USSD (Unstructured Supplementary Services Delivery)
c) WAP/GPRS
d) Phone based applications (J2ME/BREW)
e) SIM-based Application
f) Near Field Communication (NFC)
g) Dual Chip

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h) Mobile Wallet
37. Who are the stakeholders of M-Payment systems? [CO5 – L1]
The mobile payment ecosystem involves the following types of stakeholders:
 Consumers
 Financial service providers (FSPs)
 Payment service providers (PSPs)
 In-service providers (merchants), including content providers
 Network service providers (NSPs)
 Device manufacturers
 Regulators
 Standardization and industry bodies
 Trusted service managers (TSMs)
 Application developers
38. What is Micropayment schemes. [CO5 – L1]
Micropayment is intended for payment for small purchases such as from vending
machines. The mobile device can communicate directly using a Bluetooth or wireless
LAN connection to negotiate the payment and then micropayment is carried out. This
approach has been used for vending from Coca-Cola machines.
39. List out the features of Mobile Operating Systems. [CO5 – L1]
 Multitasking
 Scheduling
 Memory Allocation
 File System Interface
 Keypad Interface
 I/O Interface
 Protection and Security

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