Mobile Computing Applications

1.Define Network?

ANSWER
A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.

2.What is a Link?

ANSWER
At the lowest level, a network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Link.

3.What is a node?

ANSWER
A network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fiber. Such a physical medium is called as Links and the computer it connects is called as Nodes.

4.What is a gateway or Router?

ANSWER
A node that is connected to two or more networks is commonly called as router or Gateway. It generally forwards message from one network to another.

5.What is Multiple Access?

ANSWER
If the physical links are shared by more than two nodes, it is said to be Multiple Access.

6.Name the factors that affect the security of the network?

ANSWER
a. Unauthorized Access b. Viruses

7.What is Protocol?

ANSWER
A protocol is a set of rules that govern all aspects of information communication. (OR) "Protocol" usually refers to a set of rules that define an exact format for communication between systems

8.Define Bandwidth and Latency?

ANSWER
Network performance is measured in Bandwidth (throughput) and Latency (Delay). Bandwidth of a network is given by the number of bits that can be transmitted over the network in a certain period of time. Latency corresponds to how long it t5akes a message to travel from one end off a network to the other. It is strictly measured in terms of time.

9.Define Routing?

ANSWER
The process of determining systematically hoe to forward messages toward the destination nodes based on its address is called routing.

10.What is a peer-peer process?

ANSWER
The processes on each machine that communicate at a given layer are called peer-peer process.

11.What is Round Trip Time?

ANSWER
The duration of time it takes to send a message from one end of a network to the other and back, is called RTT.

12.What are OSI layers?

ANSWER
a. Physical Layer b. Data Link Layer c. Network Layer d. Transport Layer e. Session Layer f. Presentation Layer g. Application Layer

13.What is the difference between networking and remote networking

ANSWER
Networking: Network is group of devices, like hosts, routers, switches, hubs etc used to communicate each others. And share the information. Remote Networking: Is a collection or group of two different network or same network located in two different location and devices communicate each other in order to share the information.

14.Where do we use cross and standard cable?

ANSWER
Computer to computer ==> cross Switch/hub to switch/hub ==> cross Computer to switch/hub ==> standard

15.What is Forward Error Correction?

ANSWER
Forward error correction is the process in which the receiver tries to guess the message by using redundant bits.

16.Define Retransmission?

ANSWER
Retransmission is a technique in which the receiver detects the occurrence of an error and asks the sender to resend the message. Resending is repeated until a message arrives that the receiver believes is error-freed.

17.What is IP?

ANSWER
It’s a unique 32 bits software address of a node in a network.

18.What is usage of Sequence Number in Reliable Transmission?

ANSWER
The protocol specifies that frames need to be numbered. This is done by using sequence numbers. A field is added to the data frame to hold the sequence number of that frame. Since we want to minimize the frame size, the smallest range that provides unambiguous communication. The sequence numbers can wrap around.

19.What is Leaky bucket algorithm?

ANSWER
The leaky bucket is an algorithm used in packet switched computer networks and telecommunications networks to check that data transmissions, in the form of packets,[note 1] conform to defined limits on bandwidth and burstiness (a measure of the unevenness or variations in the traffic flow). The leaky bucket algorithm is also used in leaky bucket counters, e.g. to detect when the average or peak rate of random or stochastic events or stochastic processes exceed defined limits

20.Difference between the communication and transmission.

ANSWER
Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc. Communication means the meaning full exchange of information between two communication media.

21.What is meant by Broadcast?

ANSWER
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset thereof. It has been used for purposes of private recreation, non-commercial exchange of messages, experimentation, self-training, and emergency communication such as amateur (ham) radio and amateur television (ATV) in addition to commercial purposes like popular radio or TV stations with advertisements.

22.What is meant by Multicast?

ANSWER
In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source. Copies are automatically created in other network elements, such as routers, but only when the topology of the network requires it.

23.What is the range of addresses in the classes of internet addresses?

ANSWER
Class A - 0.0.0.0 - 127.255.255.255 Class B - 128.0.0.0 - 191.255.255.255 Class C - 192.0.0.0 - 223.255.255.255 Class D - 224.0.0.0 - 239.255.255.255 Class E - 240.0.0.0 - 247.255.255.255

24.What is packet filter?

ANSWER
Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped.

25.What is BGP (Border Gateway Protocol)?

ANSWER
It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).

26.What is Gateway-to-Gateway protocol?

ANSWER
It is a protocol formerly used to exchange routing information between Internet core routers.

27.What is RIP (Routing Information Protocol)?

ANSWER
It is a simple protocol used to exchange information between the routers. The Routing Information Protocol (RIP) is a distance-vector routing protocol, which employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from the source to a destination. The maximum number of hops allowed for RIP is 15. This hop limit, however, also limits the size of networks that RIP can support. A hop count of 16 is considered an infinite distance and used to deprecate inaccessible, inoperable, or otherwise undesirable routes in the selection process.

28.What is meant by IEEE 802.11?

ANSWER
IEEE 802.11 is a set of standards for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee (IEEE 802). The base version of the standard IEEE 802.11-2007 has had subsequent amendments

29.Define AODV Protocol?

ANSWER
Ad hoc On-Demand Distance Vector (AODV) Routing is a routing protocol for mobile ad hoc networks (MANETs) and other wireless ad-hoc networks. It is a reactive routing protocol, meaning that it establishes a route to a destination only on demand. In contrast, the most common routing protocols of the Internet are proactive, meaning they find routing paths independently of the usage of the paths. AODV is, as the name indicates, a distance-vector routing protocol. AODV uses sequence numbers on route updates.. AODV is capable of both unicast and multicast routing.

30.What is Mobile Computing?

ANSWER
Mobile computing is a form of human–computer interaction by which a computer is expected to be transported during normal usage. Mobile computing has three aspects: mobile communication, mobile hardware, and mobile software. The first aspect addresses communication issues in ad-hoc and infrastructure networks as well as communication properties, protocols, data formats and concrete technologies. The second aspect is on the hardware, e.g., mobile devices or device components. The third aspect deals with the characteristics and requirements of mobile applications.

31.What is MANETs?

ANSWER
A mobile ad-hoc network (MANET) is a self-configuring infrastructure less network of mobile devices connected by wireless links. Each device in a MANET is free to move independently in any direction, and will therefore change its links to other devices frequently. Each must forward traffic unrelated to its own use, and therefore be a router. The primary challenge in building a MANET is equipping each device to continuously maintain the information required to properly route traffic. Such networks may operate by themselves or may be connected to the larger Internet.

32.What is meant by location-based services?

ANSWER
Location-based services are a general class of computer program-level services used to include specific controls for location and time data as control features in computer programs. As such (LBS) is an information and has a number of uses in Social Networking today as an entertainment service, which is accessible with mobile devices through the mobile network and which uses information on the geographical position of the mobile device. This has become more and more important with the expansion of the Smartphone and pad markets as well.

33.What is Wireless Mesh Network?

ANSWER
A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may but need not connect to the Internet.

34.What is Wireless Sensor Network?

ANSWER
A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, humidity, motion or pollutants and to cooperatively pass their data through the network to a main location. The more modern networks are bi-directional, also enabling control of sensor activity. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance; today such networks are used in many industrial and consumer applications, such as industrial process monitoring and control, machine health monitoring, and so on.

35.What is Radio Jamming?

ANSWER
Radio jamming is the (usually deliberate) transmission of radio signals that disrupt communications by decreasing the signal to noise ratio. Unintentional jamming occurs when an operator transmits on a busy frequency without first checking whether it is in use, or without being able to hear stations using the frequency. Another form of unintentional jamming occurs when equipment accidentally radiates a signal, such as a cable TV plant that accidentally emits on an aircraft emergency frequency. The concept can be used in wireless data networks to disrupt information flow.