Download notes of lesson - Francis Xavier Engineering College

Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
FRANCIS XAVIER ENGINEERING COLLEGE
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
CS 2402- MOBILE AND PERVASIVE COMPUTING
QUESTION BANK WITH ANSWERS
http://www.francisxavier.ac.in
Page 1
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
CS 72 MOBILE AND PERVASIVE COMPUTING
Part A
UNIT - I
1. What are the types of networks?

Wired network
LAN, WAN, MAN etc.,

Wireless network
WLAN, WWAN, WMAN etc.,
2. What are the difference kinds of mobility?

User mobility

Device portability
3. What is User mobility?
User mobility refers to a user who has access to the same or similar Telecommunication service at different places. i.e) User can be mobile and the services will
follow him.
4. What is Device portability?
The communication device moves with or without the user movements and accesses
the same services.
5. List out the communication device characteristics/
 Fixed and wired
 Mobile and wired
 Fixed and wireless
 Mobile and wireless
6. List out any five applications of Mobile communication.
 Vehicles
 Emergency
 Business
 Location dependent services
 Replacement of wired networks
7.
List out some wireless devices.
 Sensor
 Embedded controllers
 Pager
 Mobile phones
 PDA(Personal Digital Assistant)
 Pocket Computer
 Notebook/ Laptop
http://www.francisxavier.ac.in
Page 2
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
8. Define SAMA.
Spread Aloha Multiple Access is a combination of CDMA and TDMA. The CDMA
better suits for connection oriented services only and not for connection less burst data
traffic because it requires programming both sender and receiver to access different users
with different codes.
9. Define CDMA.
Code Division Multiple Access systems use codes with certain characteristics to
separate different users. To enable access to the shared medium without interference. The
users use the same frequency and time to transmit data. The main problem is to find good
codes and to separate this signal from noise. The good code can be found the following 2
characteristic
1. Orthogonal.
2. Auto Correlation.
10. What are the several versions in CSMA?
There are several versions in CSMA, they are as follows
a) non-persistent CSMA
b) p-persistent CSMA
c) 1-persistent CSMA
11. What is meant by non-persistent CSMA?
In, non-persistent CSMA, stations sense the carrier and start sending immediately if
the medium is idle, if the medium is busy, the station pauses a random amount of time
before sensing the medium again and repeating this pattern.
12. What is meant by p-persistent CSMA?
In p-persistent CSMA system nodes also sense the medium, but only transmit with a
probability of p. With the station deferring to the next slot with the probability 1-p, i.e.
access is slotted in addition.
13. What is SDMA?
Space Division Multiple Access (SDMA) is used for allocating separated spaces to
users in wireless networks. The basis for the SDMA algorithm is formed by cells and
sectorized antennas which constitute the infrastructure implementing space division
multiplexing (SDM)
14. What is FDD?
In FDMA, the base station and the mobile station establish a duplex channel. The
two directions, mobile station to base station and vice versa are separated using different
frequencies. This Scheme is called Frequency Division Duplex (FDD)
15. What are the 2 sub layers in DLC?
 Logical Link Control(LLC)
 Media Access Control(MAC)
16) What is EY-NMPA?
http://www.francisxavier.ac.in
Page 3
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
Elimination yield –Non Pre-emptive Multiple Access (EY-NMPA) is a scheme which
uses several phases to sense the medium. Access the medium and for contention resolution..
Priority schemes can also be included. This is actually used in HIPERLAN1 specification.
17. What do you mean by Polling?
Polling is a strictly centralized scheme with one master and several slave stations.
The master can collect the list of stations during the contention phase and can poll these
slaves according to many schemes like round robin, random access, reservation scheme etc.
18. What are the four types of handover available in GSM?
1.Intra cell Handover
2.Inter cell Intra BSC Handover
3.Inter BSC Intra MSC handover
4.Inter MSC Handover
19.What is TETRA?
TETRA (Terrestrial Trunked Radio) systems use different radio carrier frequencies,
but they assign a specific carrier frequencies for a short period of time according to
demand. TETRA’s are highly reliable and extremely cheap.
20. What are the categories of Mobile services?
1. Bearer services
2. Tele services
3. Supplementary services
21.What are the services provided by supplementary services?
1. User identification
2. Call redirection
3. Call forwarding
4. Closed user groups
5. Multiparty Communication
22. What are types of Handover?
1. Intra-cell handover
2. Inter-cell
3. intra- BSC handover Inter-BSC
4. intra-MSC handover Inter MSC handover
23. What is meant by GPRS?
The General Packet Radio Service provides packet mode transfer for applications
that exhibit traffic patterns such as frequent transmission of small volumes.
24. What are subsystems in GSM system?
1. Radio subsystem(RSS)
2. Network & Switching subsystem(NSS)
3. Operation subsystem(OSS)
http://www.francisxavier.ac.in
Page 4
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
25. What are the information in SIM?
1. Card type, serial no, list of subscribed services
2. Personal Identity Number(PIN)
3. Pin Unlocking Key(PUK)
4. An Authentication Key(KI)
26. Define Normal Burst?
The frame used for normal data transmission within a time slot is called Normal
Burst.
27. What are the logical channels in GSM?
1. Traffic channel(TCH)
2. Control channel(CCH)
28. What is the function of Medium Access Control Layer?
The functions of Medium Access Control Layer is responsible for establishes,
maintains, and releases channels for higher layers by activating and deactivating physical
channels.
29. What is meant by GEO?
GEO means Geostationary or Geosynchronous earth orbit. GEO satellites have a
distance of almost 36000 km to the earth. Examples are almost all TV and radio broadcast
satellites, many weather satellites and satellites operating as backbone for the telephone
network.
30. What are the advantages of GEO?
Three GEO satellites are enough for a complete coverage of almost any spot on earth,
senders and receivers can use fixed antennas positions, and no adjusting is needed.
Therefore GEO’s are ideal for T.V and radio broadcasting
31. What is Handover?
The satellite is the base station in satellite communication systems and that itself is
moving. So, additional instance of handover are necessary due to the movement of the
satellite
1. Intra Satellite handover
2. Inter Satellite handover
3. Gateway handover.
4. Inter System handover.
32. What are the registers maintained by the gateway of satellite?
1. Home Location Register (HLR).
2. Visitor Location Register (VLR).
3. Satellite User Mapping Register (SUMR).
http://www.francisxavier.ac.in
Page 5
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
33. Advantages of MEO
Using Orbits around 10,000Km, the system only requires a dozen satellites
which is more than the GEO system, but much less than a LEO system. Further more these
satellites move slower relative to the earth’s rotation allowing a simpler system design.
Depending on the inclination a MEO can cover larger populations, thus requiring less
handovers.
34. Applications of Satellite?
Satellites can be used in the Following Areas
1. Weather Forecasting
2. Radio and TV broadcast Satellites
3. Military Satellites
4. Satellites for Navigation
35. What are the applications in satellites?
1.
2.
3.
4.
5.
Weather forecasting satellites
Radio & TV broadcast satellites
Military satellites
Satellites for navigation
Mobile communication
36. What are the advantages of LEO?
1.
2.
3.
4.
Data rate is 2400 bit/s
Packet delay is relatively low
Smaller footprints of LEO allows frequency reuse
Provide high elevations
37. Define the inclination angle and perigee.
The inclination angle is defined as the angle between the equatorial plane and the
plane described by the satellite orbit. An inclination angle of 0 degrees means that the
satellite is exactly above the equator. If the satellite does not have a circular orbit, the
closest point to the earth is called the perigee.
38. Define the elevation angle and footprint.
The elevation angle is defined as the angle between the centre of satellite beam and
the plane tangential to the earth’s surface. The foot-print can be defined as the area on
earth where the signals of the satellite can be received.
39. Define Header core.
Seven bytes field contains the sizes of the header and the body, the content type
of the object. Depending on this header information, the receiver may decide if it has
enough resources (memory, cpu, power, display etc) available to decode and further
process
the object.
http://www.francisxavier.ac.in
Page 6
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
40. What is MSC?
Main Service Channel (MSC) carries all user data. eg. audio, multimedia data.
41. What is FIC?
The Fast Information Channel (FIC) contains Fast Information Block(FIB) with
256bits each(16 bit checksum). An FIC carries all control information which is required for
interpreting the configuration and content of the MSC.
42. What are the different types of disk?
1. A flat disk
2. Skewed disks
3. Multi disks
43. What are the goals of DVB?
The goal of DVB is to introduce digital TV broadcasting using satellite transmission
(DVB-5) cable technology (DVB-c) and terrestrial transmission (DVB-7).
44. Name some of the formats supported by MOT?
♦Multimedia and Hypermedia information coding experts group(MHEG)
♦Join photograph’s experts group(JPEG)
♦American standard code for information interchange(ASCII)
♦Moving pictures expert group(MPEG)
♦Hypertext markup language(HTML)
♦Hypertext transfer protocol(HTTP)
♦Bitmap(BMP)
♦Graphics interchange format(GIF)
45. Give structure MOT object.
7bytes
Variable size Header core
Header Extension Body
Header core: contain the size of the header and body and the content type of the object.
Header Extension: contains additional object handling data such as repetition distance to
support caching, segmentation information and priority of the data.
Body: contains arbitrary data to be transmitted.
46. What are different interleaving and repetition schemes applied by DAB to objects and
segments?
1. Object Repetition.
2. Interleaved Objects.
3. Segment repetition.
4. Header repetition.
47. What are the advantages of DAB?
http://www.francisxavier.ac.in
Page 7
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
1. DAB can offer sound in CD like quality.
2. DAB can use single frequency network where all senders transmitting the same
radio program can operate at the same frequency.
3. DAB use VHF and UHF frequency bands.
4. DAB uses DQPSK modulation scheme.
5. DAB user COFDM and FEC.
6. DAB can transmit up to six stereo audio programmes with a data rate of 192kbit/s
each.
48. What is object repetition?
DAB can repeat objects several times. If an object A consists of four segments (A1,
A2,A3,andA4)
a single repetition pattern would be A1A2A3A4A1A2A3A4A1A2A3A4……..
42)
49. What is EIT?
Event Information Table (EIT) contains status information about the current
transmission and some additional information for set-top boxes.
50. What are the service information sent by DVB?
Digital Video Broadcast Containers are basically MPEG-2 frames. DVB sends
service information. These information are,
1. Network information table (NIT).
2. Service Description Table (SDT).
3. Event Information Table (EIT).
4. Time and Date Table (TDT)
51. What are the advantages of DVB?
1. Data rates planned for users are 6-38mbit/s for the downlink and 33-100kbit/s
for the uplink.
2. Transmitted along with TV programmes and doesn’t require additional lines or
hardware per customer.
3. Can be used in remote areas and developing countries where there is no high
band width wired network.
52. What is meant by beacon?
A beacon contains a timestamp and other management information used for power
management and roaming.
e.g., identification of the base station subsystem (BSS)
53.) What is Active scanning?
Active scanning comprises sending a probe on each channel and waiting for response.
Beacon and Probe response contain the information necessary to join the new BSS.
54. What is Passive Scanning?
Passive Scanning simply means listening into the medium to find other networks, i.e.
receiving the beacon of another network issued by the synchronization function within an
access point
http://www.francisxavier.ac.in
Page 8
Department of Computer Science and Engineering
BIG QUESTIONS
UNIT – I
1. Explain different TDMA schemes in detail.
1. Fixed TDMA,
2. Classical TDMA,
3. Slotted TDMA,
4. Carrier sense multiple access,
5. Demand assigned multiple access,
6. PRMA Packet reservation multiple access,
7. Reservation multiple access,
8. Reservation TDMA,
9. Multiple access with collision avoidance,
10. Polling, Inhibit sense multiple access.
2. Write notes on DECT and TETRA
1. System architecture,
2. Protocol Architecture
3. Write notes on UMTS and IMT – 2000
1. UMTS basic architecture,
2. UTRA FDD mode,
3. UTRA TDD mode.
4. Account on CDMA Scheme.
1. Good code,
2. Orthogonal,
3. Autocorrelation,
4. Spread aloha multiple accesses.
5. Explain broadcast systems in detail.
1. Overview
2. Cyclical repetition of data
3. Digital audio broadcasting
4. Multimedia object transfer protocol
5. Digital video broadcasting.
6. Explain satellite systems in detail.
1. History
2. Applications
3. Basics
GEO
LEO
MEO
4. Routing
5. Localization
6. Handover
http://www.francisxavier.ac.in
Page 9
CS 2402 Mobile and Pervasive Computing
Department of Computer Science and Engineering
7. Explain GSM systems in detail.
1. Mobile services
2. System Architecture
3. Radio interface
4. Protocols
5. Localization and calling
8. Discuss Handover in detail
1. Definition
2. Types
3. Handover decision
4. Intra MSC-Handover
5. Security
6. New data services
HSCSD
GPRS.
http://www.francisxavier.ac.in
Page
10
CS 2402 Mobile and Pervasive Computing
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
UNIT – II
1. What is the primary goal of IEE 802.11?
The primary goal of the standard was the specification of a simple, robust, WLAN
which offers time bounded and asynchronous services also it should be able to operate with
multiple physical layers.
2. What is meant by SIFS?
SIFS means Short Inter Frame Spacing. The shortest waiting time defined for short
control message such as acknowledgements or polling response
3. Difference between Infrared transmission and Radio transmission.
Infrared transmission
It uses diffuse light
It reflected at walls, furniture’s etc.,
Line of sight (LOS) is needed for
data transmission
Radio transmission
It uses radio waves for data
transmission
It penetrates walls, furniture’s etc.,
Line of sight (LOS) is no needed for
data transmission
4. What are Advantages of wireless LAN?
a. Flexibility,
b. Planning
c. Design
d. Robustness
e. Cost
5. What are Disadvantages of wireless LAN?
a. Proprietary Solution
b. Restriction
c. Safety and Security
d. Quality Service
6. What are Design Goals of Wireless LAN?
a.
b.
c.
d.
e.
f.
g.
h.
i.
Global Operation
Low Power
License-free Operation
Robust transmission technology
Simplified spontaneous co-operation
Easy to use
Safety and Security
Protection of investment
Transparency for application
http://www.francisxavier.ac.in
Page
11
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
7. What are the three Low Power States provided by Bluetooth?
 PARK state
 HOLD state
 SNIFF state
8. What is SCO?
SCO-stands for Synchronous Connection Oriented Link
Standard telephone (voice) connection requires symmetrical, circuit-switched, point-topoint connections. For this type of link, the master reserves two consecutive slots at fixed
intervals.
9. What are the three phases in EY-NPMA?
i. Prioritization: Determine the highest priority of a data packet ready to be sent on
competing nodes.
ii. Contention: Eliminate all but one of the contenders, if more than one sender has
the highest current priority.
iii. Transmission: Finally, transmit the packet of the remaining node.
10. What are Advantages and Disadvantages of Infrared?
Advantages:
i. Simple and extremely cheap senders and receivers which integrated in almost all
mobile devices
ii. No licenses are needed for infrared technology and shielding is very simple.
iii. Electrical devices do not interfere with infrared transmission.
Disadvantages:
i. Low bandwidth
ii. Quite easily shielded
iii. Cannot Penetrate
11. What are the system integration functions of MAC management?
• Synchronization
• Power management
• Roaming
• Management information base (MIB)
12. What do you meant by roaming?
Moving between access points is called roaming. Even wireless networks may require more
than one access point to cover all rooms. In order to provide uninterrupted service, we
require roaming when the user moves from one access point to another.
13. What is mobile routing?
Even if the location of a terminal is known to the system, it still has to route the traffic
through the network to the access point currently responsible for the wireless
terminal.Each time a user moves to a new access point, the system must reroute traffic.
This is known as mobile routing.
http://www.francisxavier.ac.in
Page
12
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
14. What are the functions which support service and connection control?
a.
b.
c.
d.
e.
Access point control function
Call control and connection control function
Network security agent
Service control function
Mobility management function
15. What are the examples for service scenarios identified in WATM?
a. Office environments
b. Universities, schools, training, centres
c. Industry
d. Hospitals
e. Home
f. Networked vehicles
16. What is BRAN?
The broadband radio access networks (BRAN) which have been standardized by European
Telecommunications Standard Institute (ETSI) are a possible choice for an RAL for
WATM. Although BRAN has been standardized independently from WATM, there is cooperation between the two to concentrate the common efforts on one goal. The main
motivation behind BRAN is the deregulation and privatization of the telecommunication
sector in Europe.
17. What are the different network types of BRAN?
a. Hyperlan1
b. Hyperlan2
c. Hyper access
d. Hyperlink
18. What is the main problem for WATM during handover?
The main problem for WATM during the handover is rerouting of all connections and
maintaining connection quality.
19. What are the different segments in ATM end-to-end connection?
An ATM end-to-end connection is separated into different segments.
1. A fixed segment is a part of the connection that is not affected by the handover
2.Handover segment is affected by the handover and is located completely within
a handover domain.
20.What is anchor point?
The Anchor point is the boundary between a handover segment and a fixed
segment.
21. What is the role of access point?
http://www.francisxavier.ac.in
Page
13
Department of Computer Science and Engineering


CS 2402 Mobile and Pervasive Computing
It acts as a bridge to other wireless and wired network
The access point poll the single wireless nodes to ensure the data rates.
22. What are different types of handover?
a.
b.
c.
d.
e.
f.
g.
Hard handover
Terminal initiated
Network initiated
Network initiated, terminal assisted
Network controlled
Backward handover
Forward handover
23. Define Piconet.
A Piconet is a collation of Bluetooth Devices which are synchronized to the same
hopping sequence. One device in the Piconet can act as master (M),all other devices
connected to master must ace as Slave (S) ,other two devices are Parked Device and Standby mode Device.
24. Define Scatternet.
The idea of forming groups of Piconet is called Scatternet.
25. List the different scenarios for wireless Piconets.
1. Connection of Peripheral devices.
2. Supporting of Ad-hoc networks.
Part - B
http://www.francisxavier.ac.in
Page
14
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
UNIT – II
1. Write short notes on
(i) Infra red vs Radio transmission
(8)
 Introduction
 Advantages
 Disadvantages
(ii) Infrastructure vs Ad-hoc Networks (8)
 Introduction
 Advantages
 Disadvantages
2. Explain IEEE802.11 standard for WLANS in detail.
 System architecture
 Protocol architecture
 Physical layer
 Frequency hopping spread spectrum,
 Direct spectrum spread spectrum,
 Infrared
 Medium access control layer
3. Discuss about HIPERLAN1 in detail.
a. Introduction
b. Phases of HIPERLAN1
c. Quality of Services
4. Write notes on WATM services and Functions.
a. Wireless mobile terminal side functions
b. Mobility supporting network side functions.
5. Write notes on WATM handover.
 Handover reference model,
 Handover requirements,
 Types of handover,
 Hand over scenarios,
 Backward handover, and
 Forward handover.
6. Write notes on location management, addressing and access point control protocol.
 Requirements for location management
 Procedures and entities
7. Discuss about HIPERLAN2 in detail.
 Introduction
 Reference model and configuration
 Different mode of operation
http://www.francisxavier.ac.in
Page
15
Department of Computer Science and Engineering
1. Centralized mode
2. Direct mode
7. Explain Bluetooth in detail.




Introduction (4)
User scenario (4)
Architecture (4)
Protocol Stack (4)
8. Discuss Wi-Fi in detail.




Definition and Introduction (4)
Applications
Architecture
Protocol Stack
(4)
(4)
(4)
9. Discuss Wi-Max in detail.




Definition and Introduction (4)
Applications
Architecture
Protocol Stack
(4)
(4)
(4)
PART – A
http://www.francisxavier.ac.in
Page
16
CS 2402 Mobile and Pervasive Computing
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
UNIT - III
1. What is mobile terminal and wireless terminal?
Mobile terminal is a standard ATM terminal with the additional capability of
reconnecting after access point change. the terminal can be moved between different access
point within a certain domain.
Wireless terminal is accessed via a wireless link, but the terminal itself is fixed, i.e.,
the terminal keeps its access point to the network.
2. What is the role of Foreign Agent?

FA can provide several services to the mobile Node during its visit to the
foreign network.
FA can have the care of address, acting as tunnel end points and forwarding
packets to the mobile node.
FA can be the default router for the MN, can also Provide security services.


3. What is the role of Home Agent?



It provides several services to Mobile Node.
It maintains location registry
It informs the MN’s current location by current COA.
4. List the type of Agent Discovery?


Agent Advertisement
Agent Solicitation
5. What is generic routing encapsulation?
Generic routing encapsulation (GRE) is an encapsulation scheme which supports
other network protocols in addition to IP. It allows the encapsulation of packets of one
protocol suite into the payload portion of a packet of another protocol suite.
6. Define COA.
The COA (care of address) 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 the tunnel.
7. What is meant by Transparency?
Mobility should remain invisible for many higher layer Protocols and applications.
The only affects of mobility should be a higher delay and lower bandwidth which are
natural in the case of mobile networks.
8. What is Generic Routing encapsulation?
Generic Routing encapsulation (GRE) allows the encapsulation of packets of one
protocol suite into the payload portion of a packet of another protocol suit.
9. What is binding Request?
http://www.francisxavier.ac.in
Page
17
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
Any node that wants to know the current location of an MN can send a binding request to
the HA. The HA can check if the MN has allowed dissemination of its current location.
10. What are the possibilities for the location of care-of-address (COA)?
The two possibilities for the location of care-of-address are:
 Foreign agent COA
 Co-related COA
11. What are the requirements for the development of mobile IP standard?
The requirements are:
a. Compatibility
b. Transparency
c. Scalability and efficiency
d. Security
12. What is COA?
Care Of Address (COA) define the current location of the MN (Mobile Node) from
an IP point of view. DHCP is a good candidate for supporting the acquisition of Care Of
Addresses.
13. What is use of DHCP?
 It is mainly used to simplify to installation and maintenance of networked
computers.
 If a new computer is connetcted to the network, DHCP can provide all the
necessary information such as Addresses of DNS server ,Default Router,Subnet
Mask,Domain Name ,IP Adresses.
14. What is Dynamic source Routing?
Dynamic Source Routing eliminates all periodic routing updates. If a node needs to
discover a route, it broadcast a route request with a unique identifier and the destination
address as parameters. Any node that receivers a route request gives a list of addresses
representing a possible path on its way toward the destination.
15. Why is need of routing?
Routing is to find the path between source and destination and to forward the
packets appropriately.
16. Define Mobile node?
Mobile node:
A mobile node is an end-system or router that can change its point of attachment to
the internet using mobile IP. The MN keeps its IP address and can continuously with any
other system in the Internet as long as link layer connectivity is given.
17. What is Encapsulation and Decapsulation?
Encapsulation is the mechanism of taking a packet consisting of packet header and
data and putting it into the data part of a new packet.
The reverse operation, taking a packet out of the data part of another packet,is
called decapsulation.
http://www.francisxavier.ac.in
Page
18
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
18. What is the advantage of On-Demand Protocols?
 The clear advantage of On-Demand Protocol is ,Scalability as long as there is light
traffic and low mobility
 Mobile Devices can utilizes longer low–power periods as long as they only have to
wake up for data transmission for route discovery
19. What do you mean by Tunneling?
A tunnel establish a virtual pipe for data packets between a tunnel entry and
tunnel end point .Tunneling is sending a packet through tunnel and received the same
without changing the e tunnel.
20. List the Advantage of IPV6?



No special mechanism is needed for securing mobile IP registration
Every node in IPV6 has auto configuration – i.e Mechanism for acquiring a
COA.
It sends binding updates to another node.
21. What is the significance of DSDV?
DSDV Routing is an enhancement of distance vector routing for ad-hoc networks.it
now add two things
 Sequence Number
 Damping
22. List the difference between wired networks and wireless networks related to routing?
 Asymmetric Link
 Redundant Link
 Interference
 Dynamic topology
23. Define Dynamic source routing.
In an adhoc networks where nodes exchanges packets from time to time. Dynamic
Source routing divides the task of routing into two separate problems
i) Routing Recovery: A node only tries to discover a route to destination if it has to
send something to this destination and there is currently no known route
ii).Route Maintenance: If a node is continuously sending packets via route, it has to
make sure that the route is held urgent. As soon as a node detects problem with the current
route it has to find an alternative node.
24. Define Damping
Transient changes in topology that are short duration should not distablize the
routing mechanism. Advertisements containing changes in topology currently stored are
therefore not disseminated further. A node waits with dissemination if these changes are
most likely not yet stable. Waiting time depends on the time between the first and the best
announcement.
BIG QUESTIONS
http://www.francisxavier.ac.in
Page
19
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
UNIT – III
1. Write Short notes on


Goals, Assumption and Requirements
Entities and Terminology
2. Explain mobile IP in detail.





IP packet delivery
Agent discovery
Agent advertisement,
Agent solicitation
Registration
Tunneling and encapsulation
IPv6.
3. Expalin the Encapsulation and its type?




Introduction
IP-in-IP Encapsulation
Minimal Encapsulation
Generic Routing Encapsulation
4. Give a detailed account of mobile ad-hoc networks.




Instant infrastructure,
Disaster relief
Remote areas
Effectiveness
5. Explain about Routing
 Asymmetric links,
 Redundant links,
 Interference,
 Dynamic topology
 Destination sequence distance vector - sequence numbers, damping
 Dynamic source routing – route discovery, route maintenance
 Alternative metrics – least interference routing.
6. Explain about Ad-hoc Routing Protocols?



Flat ad-hoc routing.
Hierarchical ad-hoc routing.
Geographic ad-hoc routing.
http://www.francisxavier.ac.in
Page
20
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
UNIT - IV
1. What are the two functions of the transport layer in the internet?
The two functions of the transport layer in the internet are
1. Check summing over user data and
2. Multiplexing/ demultiplexing of data from applications.
2. What is called the exponential growth of the congestion window?
The sender always calculates congestion window for a window start size of the
congestion window is one segment. Sender sends one packet and waits for
acknowledgement. If acknowledgement arises it raises the level of congestion window by
one. If sender sends two packets if acknowledgement arises it raises the level of congestion
window by two. This scheme raises the level of congestion window every time the
acknowledges come back, which takes roundtrip time (RTT).This is called the exponential
growth of the congestion window.
3 Advantages of I-TCP:
•I-TCP does not require any changes in the TCP protocol as used by the hosts in the
fixed network or other hosts in a wireless network that do not use this optimization.
•Without partitioning retransmission of lost packets would take place between
mobile host and correspondent host across the whole network. •Optimization of new
mechanisms is quite simple to be done in I-TCP as they only cover a single hop.
•The short delay between the mobile host and foreign agent can be determined and
is independent of other traffic streams. Therefore an optimized TCP can use precise timeouts to guarantee retransmission as fast as possible.
•Partitioning into two connections also allows the use of a different transport layer
protocol between the foreign agent and the mobile host or the use of compressed headers
etc. The foreign agent can act as a gateway to translate between different protocols.
4. Disadvantages of I-TCP?
1. The loss of the end to end semantics of TCP causes problems if the foreign agent
portioning the TCP connection crashes.
2. An increased handover latency is more problematic in practical use
3. The foreign agent must be a trusted entity because the TCP connections end at
this point.
5. Define Slow Start?
TCP’s reaction to a missing acknowledgement is quite drastic, but necessary to get
rid of congestion. The behaviour TCP shows after the detection of congestion is called Slow
start.
6. How does data transmission takes place?
Data transmission takes place using network adapters, fibre optics, copper wires,
special hardware for routers etc.
7. What is mean by Slow Start?
http://www.francisxavier.ac.in
Page
21
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
TCP’s reaction to a missing acknowledgement is quite drastic, but necessary to get
rid of congestion fast enough. The behaviour TCP shows after the detection of cogestion is
called slowstart.
8. What is mean by SCPS-TP?
The set of protocols developed for space communication is known as space
communications protocol standards (SCPS), the extended TCP is called SCPS-transport
protocols, (SCPS-TP).
9. What are Advantage and Disadvantage of Mobile TCP?
Advantage:
i. M-TCP maintains the TCP end-to-end semantic. The SH does not send any ACK
itself but forwards the ACKs from the MH.
ii. If the MH is disconnected, M_TCP avoids useless retransmissions, slow starts or
breaking connections by simply shrinking the sender’s window to 0;
iii. Since M-TCP does not buffer data in the SH as I-TCP does, it is not necessary to
forward buffers to a new SH.
Lost packets will be automatically retransmitted to the new SH.
Disvantage:
i. As the SH does not act as proxy as in I-TCP, packet loss on the wireless link due to
bit errors is propagated to the sender.
M-TCP assumes low bit error rates, which is not always a valid assumption.
ii. A modified TCP on the wireless link not only requires modification to the MH
protocol software but also new network elements like the bandwidth manager.
10. What is Fast retransmit?
In TCP, a receiver sends acknowledgements only if it receive any packets from the
sender. Thus receiving acknowledgements from a receiver shows additionally that the
receiver continuously receives something from the sender. Therefore, the gap in the packet
stream is not due to severe congestion, but a simple packet loss due to a transmission error.
The sender can now retransmit the missing packets before the timer expires. This behavior
is called fast retransmit.
11. What is fast retransmit?
The gap in the packet stream is not due to severe congestion, but a simple packet
loss due to a transmission error. The sender can now retransmit the missing packet before
the timer expires. This behavior is called fast retransmit.
12. What is fast recovery?
The receipt of acknowledgement shows that there is no congestion justifying a slow
start. The sender can continue with the current congestion window. The sender performs a
fast recovery from the packet loss. This mechanism can improve the efficiency of TCP
dramatically.
13. List the type of TCP.
http://www.francisxavier.ac.in
Page
22
Department of Computer Science and Engineering



CS 2402 Mobile and Pervasive Computing
Indirect TCP (I-TCP)
Snooping TCP
Mobile TCP
14. What is goal of Mobile – TCP?


This approach as the same goals as I-TCP and Snooping TCP to prevevt the
sender window from shrinking , if bit errors or disconnetion cause current
Problems.
M-TCP wants to improve the overall throughput,Lower the Delay,Maintain end
to end Semantics of TCP and to provide more efficient handover.

15. List some of the approaches that may help wireless access for HTTP and HTML?





Image Scaling
Content Transformation
Content Extraction
Special Language and Protocols
Push Technologies.
16. What is HTTP?
The Hypertext transfer protocol is a stateless, lightweight, application level protocol for
data transfer between servers and clients. An HTTP transaction consists of an HTTP
request issued by a client and an HTTP response from the server. Stateless means that all
HTTP transactions independent of each other.
17. What is image scaling?
If a page contains a true color, high-resolution picture, this picture can be scaled
down to fewer colors, lower resolution, or finally to only the title of the picture. The user
can decide to download the picture separately. Further one can offer clipping, zooming, or
detail studies to users if they are interested in a part of the picture.
18. What is WAP?
Wireless application protocol (WAP) is a common effort of many companies and
organizations to set up a framework for wireless and mobile web access using many
different transport systems. Eg. GSM, GPRS, UMTS.
19. What is WML Browser?
WML Browser is a library that provides several functions typical for a browser,
such as prev to go back one card or refresh to update the context of the user interface.
20. Define WAP
WAP is Wireless Application Protocol.It is the basic Objetive of the WAP forum are
to bring diverse Internet content and others data service to digital cellular phones and
other wireless,mobile terminals.Moreever a protocol suite should enable global wirless
communication across different wireless network technologies.All WAP forum solution
http://www.francisxavier.ac.in
Page
23
Department of Computer Science and Engineering
must be:interoperable,scaleable,efficient,reliable.
21. List out the Layers of WAP?
1.
2.
3.
4.
5.
6.
Application Layer
Session Layer
Transaction Layer
Security Layer
Transport Layer
Bearer Services.
22. List out the features of WML?




Text and images
User interaction
Navigation
Context Management
23. List three services of WTA?



Common network services
Network specific services
Public services
24. List the advantages of WML Scripts over WML?




Validity check of user input
Access to device facilities
Local user interaction
Extensions t the device software
BIG QUESTIONS
UNTIT – IV
1. Write notes on traditional TCP.
 Congestion control,
 Slow start,
 Fast retransmit/ fast recovery,
 Implications on mobility.
2. Write notes on wireless TCP.
 Indirect TCP,
 Snooping TCP,
 Mobile TCP,
 Fast retransmit/fast recovery,
http://www.francisxavier.ac.in
Page
24
CS 2402 Mobile and Pervasive Computing
Department of Computer Science and Engineering
CS 2402 Mobile and Pervasive Computing
 Transmission/time t out freezing,
 Selective retransmission,
 Transaction oriented TCP.
3. Write notes on WDP and WTLS.
 WDP with diagrams.
 WTLS with diagrams.

4. Write notes on wireless transaction protocol..
 Figure and explanation about
 WTP class 0,
 Class 1 and
 Class 2.
5. Write notes on wireless sessions protocol.
 WSP/B over WTP and
 WSP/ B as connectionless session service
6. Explain Traditional TCP Architecture-Types- Frame formats-Explanation


Traditional TCP Architecture
Types
I-TCP
M-TCP
Snooping TCP
Frame Formats



7. Describe about World Wide Web?



Introduction
HTML
HTTP
8. Describe about WAP?



Introduction
Architecture
WAP Components
UNIT – V
http://www.francisxavier.ac.in
Page
25
Department of Computer Science and Engineering
CS 72 Mobile and Pervasive Computing
1. What is Pervasive Computing?
Pervasive computing is a new dimension of personal computing that integrates
mobile communication, embedded computer system, consumer electronics, and power of
the Internet.
It is based on the combination of key technologies, web age research, and
development methodologies.
2. What are the basic aspects of a Pervasive Computing environment?
There are three aspects
1. Personal Perception
2. Technology Aspects
3. Business Aspects
3. What are the major choices available for battery design in Pervasive Computing
Devices?
1. Nickel Cadmium (NiCad) cell –Rechargeable batteries, heavy and hard tendency
to lose capacity.
2. Nickel –Metal Hydride (NiMH) – better capacity with less weight
3. Lithium ion (Li ion) batteries –lighter and better energy density.
4. Give any five application of pervasive computing?
1. Retail Business
2. Airline check-in and booking
3. Sales force automation
4. Healthcare
5. Tracking
5. What are the different display device technologies available?
1. Dual Scan Display (DSTN)
2. Light emitting organic diode (OLED) or light emitting polymer technology
(LEP)
3. Chip on glass (CoG)
4. Liquid Crystal on glass (LCoG)
6. What are the 2 basic elements needed with respect to connectivity in Pervasive
Computing?
Pervasive computing devices are connected to applications and services through
internet. Protocols used for device to device and device to server connectivity.
7. Compare and contrast the 1G 2G and 3G technologies.
Comparisons between 1G and 2G:
The greatest disadvantage as concerned to 1G is that with this we could contact with
in the premises of that particular nation, where as in case of 2G the roaming facility a semiglobal facility is available
http://www.francisxavier.ac.in
Page
26
Department of Computer Science and Engineering
CS 72 Mobile and Pervasive Computing
Comparisons between 2G and 3G:
 In comparison to 2G customers will have to pay a relatively high license fee for 3G.
 The network construction and maintenance for 3G is much expensive than 2G.
 From the point of view of customers, expenditure will be excessively high if they
make access to various facets of 3G.
8. What is meant by 2.5G technology?
In between 2G and 3G there is another generation called 2.5G. Firstly, this mid
generation was introduced mainly for involving latest bandwidth technology with addition
to the existing 2G generation. To be frank but this had not brought out any new evolution
and so had not clicked to as much to that extend.
9. List the different types of memories available for Pervasive Computing Devices.
1. Small Removable disk drive
2. Hard disk for permanent data
3. Non-volatile Flash Memory
4. Random access memory
5. Static random access memory
6. Uni-transister random access memory
7. magneto-resistive random access memory
10. Describe EPOC Operating System.
EPOC was originally created by Psion but is now maintain by Symbian Company.
This was founded by Psion, Motorola, Panasonic, Ericsson and nokia.this OS desined
specifically for mobile phones
There are two versions:
1. EPOC16 for 16 bit processor
2. EPOC32 for 32 bit processor
Current version is EPOC release 5 – which is available for NEC v30H(16 bit version) and
ARM/Strong ARM(32 bit version) processors.
11. What is PALM OS?
Palm OS is the computer operating system that provides a software platform for the
Palm series of handheld personal digital assistants (PDAs) made by Palm Inc.According to
Palm, Palm OS was designed from the beginning to fit into a palm-size device of a specific
size and with a specific display size.
Versions are: Palm OS 1.0,2.0,3.0(3.1-3.5),4.0(4.1-4.2),5.0(5.1 – 5.5)
12. Explain briefly about BE OS.
BeOS is an operating system for personal computers which began development by
Be Inc. in 1991. BeOS was optimized for digital media work and was written to take
advantage of modern hardware facilities.
13. What are the features of BeoS?
1. User management.
2. Task management
http://www.francisxavier.ac.in
Page
27
Department of Computer Science and Engineering
CS 72 Mobile and Pervasive Computing
3. Memory management , 4. Addition features
14. Compare and contrast Windows and Linux OSes.
Both Windows and Linux come in many flavors(XP,NT versions etc). All the flavors
of Windows come from Microsoft, the various distributions of Linux come from different
companies (i.e. Linspire, Red Hat, SuSE, Ubuntu, Xandros, Knoppix, Slackware, Lycoris,
etc. ).
All the Linux distributions released around the same time frame will use the same
kernel. They differ in the add-on software provided, GUI, install process, price,
documentation and technical support. Both Linux and Windows come in desktop and
server editions.
Linux is customizable in a way that Windows is not.
15. Describe briefly about the tegic T9 dictionary mode.
T9, which stands for Text on 9 keys, is a patented predictive text technology for
mobile phones, originally developed by Tegic Communications, now part of Nuance
Communications.T9 is used on phones from LG, NEC, Nokia, Samsung Electronics,
Siemens, Sony Ericsson, Sanyo, Sagem and others. It was also used by Texas Instruments
PDA Avigo during the late '90s.
16. What is ‘Octave’?
Octave is a free computer program for performing numerical computations (created
as part of the GNU project) which is mostly compatible with MATLAB.
 Octave is written in C++ using STL libraries.
 Octave has an interpreter that interprets the Octave language.
 Octave itself is extensible using dynamically loadable modules.
 Octave interpreter works in tandem with gnu plot and Grace software to create
plots, graphs, and charts, and to save or print them.
17. What is meant by Bio-Metrics?
Biometrics is the science and technology of measuring and analyzing biological data.
In information technology, biometrics refers to technologies that measure and analyze
human body characteristics, such as DNA, fingerprints, eye retinas and irises, voice
patterns, facial patterns and hand measurements, for authentication purposes.
Biometric characteristics can be divided in two main classes:
1. Physiological
2. Behavioral
18. What is a ‘Haptic Interface’?
A user interface that allows a computer or robotics-driven device to interpret the
sensation of touch. Haptic interfaces are used in surgical rehearsal systems to imitate the
body’s reaction to touch, and incorporated into minimally invasive instruments to give
surgeons a better 'feel' for the tissue without invasive access.
19. What are three steps involved in the process of Synchronization?
http://www.francisxavier.ac.in
Page
28
Department of Computer Science and Engineering
CS 72 Mobile and Pervasive Computing
1. Pre-Synchronization
2. Synchronization
3. Post Synchronization
20. Why is device management important in Pervasive Computing?
1. Tracking the device location
2. Device user relationship
3. Version control of device and software that are out in the field
4. Software updates
5. Installation of new software.
6. Providing secure access to device information.
UNIT – V
1. Discuss in detail about any two Pervasive Applications of your choice in detail.
1. Retail Business
2. Airline check-in and booking
3. Sales force automation
4. Healthcare
5. Tracking
2. Explain about the various hardware components involved in Pervasive Computing
Devices.
1. Batteries (4)
2. Displays (4)
3. Memory (4)
4. Processors (4)
3. Write brief notes on the following.
a. Speech Recognition (4)
b. Handwriting recognition (4)
c. Haptic Interfaces (4)
d. QWERTY and FITALY keyboards (4)
4. Explain in detail about Bio-Metrics. List out its merits and demerits.
1. Description of Bio-Metrics (8)
2. Advantages (4)
3. Disadvantages (4)
5. How is synchronization carried out in a Pervasive Environment? Write brief notes on
the syncML tool.
1. Synchronization Principles (3)
http://www.francisxavier.ac.in
Page
29
Department of Computer Science and Engineering
CS 72 Mobile and Pervasive Computing
2. Synchronization scenarios with figure (5)
3. SyncML tool with Frame work (8)
6. What are the various issues related to device management and how are they dealt with?
1. Device Management Challenges (3)
2. Software distribution (3)
3. Approaches to solve issues (10)
7. Explain how a Pervasive Web Application can be secured using an ‘Authentication
Proxy’.
1. Basic and Digest Authentication (4)
2. Form based authentication (4)
3. SSL/TLS client authentication with client certificates (4)
4. Authentication using smart cards (4)
8. Discuss in detail about the access form PCs.
1. Smart card based Authentication with diagram (4)
2. Implementation with diagram (4)
3. Login (4)
4. Ordering goods & Menu (4)
10. How is access carried out in case of a PDA?
1. Extending the example application with PDA
2. Implementation for synchronized devices.
3. Implementation for integrity connected devices.
11. Explain in detail about access via WAP.
1. WAP Functionality and Architecture.
2. Implementation
3. Applications.
http://www.francisxavier.ac.in
Page
30
Department of Computer Science and Engineering
http://www.francisxavier.ac.in
Page
31
CS 72 Mobile and Pervasive Computing