Tuesday 2 April 2013
CS9251 MOBILE COMPUTING 2MARKS 16MARKS QUESTION PAPERS
MOBILE COMPUTING
2 Mark Questions
UNIT I
1) What are the
categories of Mobile services?
• Bearer services
• Tele services
• Supplementary
services
2)What are the
services provided by supplementary services?
• User identification
• Call redirection
• Call forwarding
• Closed user groups
• Multiparty
Communication
3) 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
4.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.
5)What are subsystems
in GSM system?
• Radio subsystem(RSS)
• Network &
Switching subsystem(NSS)
• Operation
subsystem(OSS)
6)What are the
information in SIM?
• card type, serial
no, list of subscribed services
• Personal Identity
Number(PIN)
• Pin Unlocking
Key(PUK)
• An Authentication
Key(KI)
7)Define Normal Burst?
The frame used for
normal data transmission within a time slot is called Normal
Burst.
8)What are the logical
channels in GSM?
• Traffic channel(TCH)
• Control channel(CCH)
9) 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)
10. What are the
reasons for delays in GSM for packet data traffic.
1. Different data
rates provided by traffic channels are low.
2. Authentication and
encryption also makes the packet data transmission low.
3. Various
interferences and noises from the channel also causes delay.
11. List out
disadvantages of cellular system.
1. Self – jamming
2. Near – far problem
3. Soft Handoff
12. How much of the
original GSM network does GPRS need. Which elements of the network perform the
data transfer.
GPRS is an enhancement
of SM. It uses same physical channel as GSM and only new
logical GPRS radio
channels are defined.
Elements needed for
data transfer:
1. GPRS support nodes
(GSN)
2. Gate way GPRS
Support Node (GGSN)
3. Servicing GPRS
Support Node (SGSN)
4. GPRS Register (GR)
13. Explain the
various entities available in radio subsystem
1. BSS: It performs
all function necessary to maintain radio connections to a MS.
2. BTS: It comprises
all radio equipments
3. BSC: It basically
manage BTSs.
4. MS: It comprises
all user equipment and software needed for communication within a
GSM network.
14. . Explain the
various entities available in NSS.
NSS consist of
following switches and databases.
1. MSC: They setup
connection to other MSCs and to BSCs via A interface.
2. HLR: It is the most
important data base which stores all user relevant information.
3. VLR: It is a
dynamic data base which stores all important information needed for MS
users currently in the
LA that is associated to MSC.
15. Explain the
various systems available in Operation Subsystem.
Operating subsystem :
It contains necessary functions for network operation and
maintenance.
1. OMC: It manages
traffic monitoring , accounting and billing
2. AuC: It is used to
protect user identity and data transmission.
3. EIR: It stores all
device identifications registered for this network.
16. Explain the
various control channels available in GSM.
1. BCCH: A BTS uses
this channel to signal information to all MSs with in a cell.
2. CCCH: All
information regarding connection setup between MS and BS are
exchanged via CCCH.
3. DCCH: It is used to
exchange large amounts of data in less time.
17.) 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.
18) What are the
functions which support service and connection control?
>Access point
control function
>Call control and
connection control function
>Network security
agent
>Service control
function
>Mobility management
function
19. If 8 speech
channels are supported on a single radio channel, and it no guard band is
assumed, what is the
number of simultaneous users can be accommodated in GSM?
A time slot is GSM can
only be used by one user to transmit or receive during one of the
transmission (radio)
channel. That is, we can accommodate 1 user in one time slot.
Therefore, for 8
speech channels we can accommodate 8 simultaneous users in GSM.
20. Define Base
Station Subsystem GPRS protocol (BSSGP).
The Base Station
Subsystem GPRS protocol (BSSGP) is used to convey routing and QoSrelated
information between
the BSS and SGSN. BSSGP not perform error correction and works
ontop of a Frame Relay
(FR) network.
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 are Advantages
of wireless LAN?
Flexibility,
Planning,
Design,
Robustness,
Quality Service,
Cost,
Proprietary Solution,
Restriction,
Safety and Security
3) What are Design
Goals of Wireless LAN?
Global Operation
Low Power
License-free Operation
Robust transmission
technology
Simplified spontaneous
co-operation
Easy to use
protection of
investment
Safety and Security
Transparency for
application
4)What are the three
Low Power States provided by Bluetooth?
PARK state
HOLD state
SNIFF state
5) What are the
examples for service scenarios identified in WATM ?
>Office
environments
>Universities,
schools, training, centres
>Industry
>Hospitals
>Home
>Networked vehicles
6) What are the
different network types of BRAN?
>Hyperlan1
>Hyperlan2
>Hyper access
>Hyperlink
7) 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.
8. Why is the physical
layer IEEE 802.11 subdivided.
Physical layer is
subdivided into ,
PLCP (physical layer
convergence protocol) . It provides a carrier sense signal called
CCA (Clear channel
assessment) and provides a common PHY Service Access Point SAP
independent of
transmission technology.
PMD : Physical Medium
Dependent Sublayer: It handles modulation and encoding /
decoding of signals.
9. How is mobility
restricted using WLANs.
WLAN: Mobile
restricted with respected to the access point. When moving the mobile
entity needs to change
network access point. Every moblile entity (Person, terminal) must have its own
identity. An identifier is assigned uniquely to one mobile entity.
10. What is HIPERLAN?
HIper Performance
Radio LAN : HIPERLAN It is a new standard for radio LAN
developed by ETIS.
Offers interoperability standard which specifies a common air interface.
EITS developed a
standard that would be equivalent in performance to wired LAN such as
Ethernet.
10) What is EY-NMPA?
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
11. Is IEEE 802.11 and
Wi-Fi same. State the purpose of WiFi.
No, IEEE 802.11 and
Wi-Fi are different.
IEEE 802.11 is a
Wireless LAN (WLAN). Where as, Wi-Fi uses WPA ( Wi-Fi Protected
Access) to accelerate
the introduction of strong security into WLANs. WPA use the security
mechanisms of IEEE
802.11i. In other words it is a security mechanism in WLAN, which dealt about
authentication, key management, and data transfer privacy.
12. Why Bluetooth
specification comprises so many protocols and components?
Bluetooth
specification comprises so many protocols and components because,
The protocol stack of
Bluetooth can be divided into a
1. Core Specification,
which describes the protocols from the physical layer to the data link
control together with
management functions.
2. Profile specification,
which describes the protocols and functions needed to adopt the
wireless Bluetooth
technology to legacy and new applications.
13. What are the
different phases in HIPERLAN?
The different phases
in HIPERLAN are
1. Prioritization
phase
2. Contention phase,
and
3. Transmission phase.
14. What is
scatternet?
One Bluetooth device
can operate simultaneously on two piconets, acting as a bridge
between the two. A
Conglomeration of two or more piconets is called a scatternet.
15. What are the elements
of Bluetooth core protocols?
The elements of
Bluetooth core protocols are
1. Radio.
2. Base band,
3. Link manager
protocols,
4. Logical link
control & adaptation protocol (L2CAP)
5. Survive discovery
protocol.
16. List the two types
of data bursts specified by HIPERLAN.
The two types of data
bursts specified by HIPERLAN are,
1. LBR – HBR data
burst
2. LBR data burst.
17. Define Roaming.
If a user walks around
with a wireless station, the station has to move from one access
point to another to
provide uninterrupted service. Moving between access point is called
Roaming. The term
handover and handoff is used in the context of mobile or cellular system
would be more
appropriate as it is simply a change of the active cell.
18. What are the
phases in Elimination yield –Non Pre-emptive Multiple Access (EY-NMPA).
Elimination yield –Non
Pre-emptive Multiple Access (EY-NMPA) divides the medium
access of different
competing nodes into three phases:
1. Prioritization :
Determine the highest priority of a data packet ready to be sent by
competing nodes.
2. Contention :
Eliminate all but one of the contenders , if more than one sender has the
highest current
priority.
3. Transmission:
Finally, transmit the packet of the remaining node.
19. What are the
general extention of ATM.
1. Location Management
2. Mobile Routing
3. Handover Signalling
4. Qos and traffic
Control
5. Network Management
20. Example for WATM.
1. Office Environment
2. Universities,
schools, training centers\
3. Industry
4. Hospitals
5. Home
6. Networked vehicles
etc.
MOBILE COMPUTING
2 Mark Questions
UNIT III
1. 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.
2) What are the
functions which support service and connection control?
>Access point
control function
>Call control and
connection control function
>Network security
agent
>Service control
function
>Mobility
management function
3) 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
4) 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.
5) 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
VMN. Packet delivery toward the MN is done using the tunnel.
6) 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.
7)What is Binding
Request?
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.
8) What are the
possibilities for the location of care-of-address (COA)?
The two possibilities
for the location of care-of-address are:
i.Foreign agent COA
ii.Co-related COA
9) 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.
10) 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.
11) Why is need of
routing?
Routing is to find the
path between source and destination and to forward the packets
appropriately.
12) 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.
13) 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.
14) 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 problem
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.
15. Define table
driven routing protocol and on-demand routing protocol.
Table driven routing
is the DSDV routing protocol. Here distance vector is used as
Routing Information
Protocol. It works well in the addition of two fields.
1. Sequence number :
Each routing advertisement comes with a sequence number. The
sequence number will
avoid loops.
2. Damping : Transient
changes in topology that are of short duration should destabilise the
routing mechanisms.
The advertisement that
contain the temporary changes are not disseminated. A node
works with
dissemination if the changes are temporary.
16. Define on-demand
routing protocol.
The routing is done by
two separate problem.
1. Route Discovery: A
nods tries to discover a route to a destination only if it has a
packet to send and
currently there is no route between the source and destination.
2. Route Maintenance:
If a node is continuously sending packets via a route, it has to
make sure that the
route is held upright. As soon as a node detects the problems
with current route, it
has to find an alternate route.
17. Why is routing and
mobility are important issues of an adhoc network.
Mobility is the
greatest problem for routing in adhoc network, because there are
frequent changes in
topology, so snap shot is valid for very short period of time.
Routing is difficult
because of the asymmetric link.
18. Give the purpose
of reverse tunneling
When the MN sends
packets to CN reverse tunnel is needed because,
a. Firewalls: all the
network is connected to internet via firewall. The firewall
will filter the packet
from malicious address.
b. Multicast: Reverse
tunnel is needed for mobile node to participate in a
multicast group
c. TTL: A mobile node
sense a packet with a certain TTL and still in the home
network itself. When
the MN has moved to FN this TTL is very low and will
not reach the
destination.
19. Give any two
reasons for why routing in mobile ad hoc networks complicated?
Routing is complicated
because of
1. Asymmetric links
2. Redundant links
3. Interference
4. Dynamic topology
20. What is tunneling?
Tunneling is used to
forward packets between HA and COA. Tunnel establishes a
virtual pipe for the
data packets between tunnel entry and end point. Tunnel is
nothing but sending
packet through tunnel using encapsulation
MOBILE COMPUTING
2 Mark Questions
UNIT IV
1)What are the
requirements for the development of mobile IP standard?
The requirements are:
a. Compatibility
b. Transparency
c. Scalability and
efficiency
d. Security
2)What are the two
functions of the transport layer in the internet?
The two functions of
the transport layer in the internet are check summing over user data
and multiplexing
de-multiplexing of data from applications.
3) What is called the
exponential growth of the congestion window?
The sendor always
calculate 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 packet if
acknowledgement arrises 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.
4) 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 time-outs
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.
5) Disadvantages of
I-TCP:
• The loss of the end
to end semantics of TCP cause problems if the foreign agent
portioning the TCP
connection crashes.
• An increased
handover latency is more problematic in practical use.
• The foreign agent
must be a trusted entity because the TCP connections end at this point.
6. 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
7) What is WMLBrowser?
WMLBrowser 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.
8) 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 must
be:interoperable,scaleable,efficient,reliable.
9)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.
10) What are the
Advantages of MobileTCP?
Advantage:
i. M-TCP maintains the
TCP end-to-end semantice. 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.
11) What are the
Disadvantages of MobileTCP?
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.
12) 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 behaviour is called fast retransmit.
13) Define 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.
14) 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.
15)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.
16. What are the
solutions for the problem with HTTP and HTML?
HTTP HTML
1. Bandwidth delay
High performance system
2. Caching High
Resolution Display
3. POST Mouse,.sound
system, large hard disk
17. Give tha basic
objectives of WAP?
To provide
1. Internal content
access to mobile phones
2. Data Services
3. Protocol suite for
global wireless communication across the different technologies.
18. Give any two
capabilites of WML script that is not supported by WML.
1. Validity check for
user input.
2. Access to device
facilities.
3. Local user
interaction
4. Extension to device
software.
19. Mention a few WCMP
messages.
1. Destination
unreachable
2. Parameter problem
3. Message too big
4. Reassembly failure
and Echo Request/Reply.
20. Objectives of OMA
(Open Mobile Alliance).
1. Internet content
like webpages and push services.
2. Data Services
3. Protocol suite for
global wireless communication across the different technologies.
4. Interoperable,
scalable, efficient, Reliable and secure.
UNIT V
1. What is pervasive computing?
Pervasive computing is
also called as ubiquitous computing is the trend toward
embedding micro
processors in everyday objects so that they can communicate information. It
refers to the computer contained in common place so that people are unaware of
their presence. All these devices communicate with each other over wireless
networks without any interaction required by the user.
2. Pervasive computing is a combination of 3 technologies
a) Micro -electronic
technology
This technology
provides small powerful device and display with low
energy consumption.
b) Digital
communication technology
The technology
provides higher bandwith, high data transfer rate at lower cost
and World Wide
roaming.
c) The International
standardization
This standardization
in done through standardization bodies and industry to
provide the frame
works for integrating all components into an interoperable system with
security, service and
billing systems.
3. Technologies used in 3G mobile systems
a) GSM/UMTS
b) imode system
GSM/UMTS
This technology is
based on the harmonized 3G Radio interface.
This system is supported
by major telecom standard organization.
The service offered
are World Wide roaming, supports WAP and seamless
integration from GSM
to UMTS
• IMODE SYSTEM
This system was
developed by NTT Docomo.
This is proprietary
system. The concepts used are high speed, packet
switched network and
IP.
The system was
developed in Japan and now being used by others.
4. Strength of GSM.
1. Supported by major
standard organization suppliers.
2. Has large user
base.
Strength of IMODe
1. Maturity.
2. Rich set of
application.
3. Affinity of
internet with respect to protocol and content representation.
4. Uses CHTML ie
compact hypertext markup language , easy to migrate from internet
application to mobile
applications.
5. DSTN
1. Dual scan DSTN is
generally used in PDA.
2. This method
controls display element via passive matrix addressing.
3. This method
consumes less power
4. Has superior
display performance hence used in laptops.
6.Techniques followed in Smart phone and PAD.
1. They store their OS
code and application data in non- volatile flash memory and battery
backed RAM.
2. They are based on
semi conductor techonology.
3. Hence they need
less power and provide faster access.
4. The capacity is
from 2 to 16 MB.
5. Expansion slots are
available for additional to be plugged in.
Flash memory and
static RAM can be used, frequently changed data is kept in SRAM.
7.Crusoe Processor.
The power saving
technology attempts to reduce the total number of transistor and replaced
function by software.
Such provides better performance by consuming less power.
E.g. Crusoe processor
by transmitter.
This processor is very
small processor designed as 128 bit very long instruction word (VLIW).
The processor is
capable of executing up to 4 operations per cycle.
8. Define FAR and FRR.
False Acceptance Rate(
FAR) is defined as the probability that the system will accept a wrong
user.
False Rejection Rate
(FRR) is defined as the probability that the system will reject a correct user.
For a SIM with PIN the
FAR=0.01%
FRR= 0%.
9. OS Functionality.
1. User interface:
Graphical Input/ Output.
2. Memory Management:
Database, space, runtime systems, variables.
3. System Management:
Events, alarms, data, time.
4. Communication
layer: Communication via a. TCP/IP b. InfraRed.
10. Define Wireless Protocols.
In these protocols no
cables are needed inorder to communicate with each other devices.
E.g. of wireless
protocols are
OBEX, IrDA, Bluetooth,
802.11B.
11. Characteristics of Bluetooth.
1. Frequency band.
Bluetooth operates in
the 2.45 GHz ISM band.
2.Security.
Security mechanism is
defined by the Bluetooth.
3.Transmitting
Capabilities.
Bluetooth is one
directional and range is up to 10m. The transmitting services supplied are
synchronous and
asynchronous.
4. Bandwidth.
The bandwidth is up to
1Mbps.
5. Speech
The Bluetooth supports
3 digital channels simultaneously.
6. Cost: Bluetooth is
expensive.
12. Compare the Generations of mobile systems.
Generations 1G 2G 2+G
3G
Protocol AMPS, C-Net
GSM,TDMA,CDMA GPRS,
HSCSD,EDGE
UMTS,WCDMA
TECHNOLOGY Analogy
Circuit
-Switched
Digital Circuit -
Switched
Digital Circuit or
packet Switched
Digital packet
Switched
SPEECH
QUALITY
POOR HIGH HIGH HIGH
BANDWIDTH LOW LOW
MEDIUM HIGH
SECURITY None
Depending on
protocol ,Low to
high
HIGH HIGH
14. Why IPV4 cannot be used with mobile devices.
IPV4 has the
constraints that the devices are stationary when there are mobility the
devices attaches with
new point of attachment with the different IP address. Then the connection
with the old address
will be broken.
Mobile IP provides a
way to solve the problem and tells how to mobile devices can
communicate over IPV4.
15. Features of Mobile IPV6.
1. Auto Configuration
and neighbour discovery.
2. With the use of
above a mobile node can create or obtain a topologically correct CoA for the
current point of attachment without the need of FA.
3. Strong encryption
and authentication features.
4. Supports greater
degree of mobility when compared with IPV4.
5. Mobility
transparency is yet to achieve.
16. Define IP Addressing.
A device wishing to
join UPnP network should get an IP address. To get the address there
are two methods.
1. Using DHCP.
2. Using Auto IP.
The devices sends a
requests to the DHCP server. If no server answers the request within
a reasonable time then
the device uses AutoIP to generate an IP address from the set of
reserved IP addresses.
17. Define the concepts of Security.
1. Identification.
2. Authentication.
3. Authorization.
4. Transaction
authorization.
5. Non-repudiation.
18. Define Authentication.
Authentication is to
prove that who the individuals say they are .
The most common
Authentication is user ID and Password.
Authentication can
also be done by SIM. The Authentication is executed between the
SmartCard on the
client and the Authentication software on the server side.
Password provided by
the user has to be given to the smart Card before a signature can be
obtained to ensure
Authentication.
19. Define TAN (Transaction Authorization Numbers).
They are secret
numbers delivered to the legitimate user in blocks. The organization that
sends the TAN to the
user ensure that users are aware of TAN upon the receipt of the TAN the user
must acknowledge and sign stating that they will keep the TAN blocks secretly
and never reveal to any one.
20. Challenges of Device Management.
1. Tracking device
location.
2. Device-user
relationship (Single owner or multiple owner)
3. Version control of
devices and software
4. Software updates of
existing devices.
5. Installation of new
software on existing devices.
6. Providing secure
access to device information.
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