The Ad Hoc on-Demand Distance Vector - Assignment Example

Quiz 1. A Mobile IP give a second IP address to a host who want to be mobile to ensure that even if he change his point of attachment in the internet he will still be identified by her original IP address. Home address IP is used when the device is attached in the home network and care- of address is used when it is away in foreign network. Quiz 1. B Home address- Mobile devices have home address IP; this is IP address which is assigned to device in its home network. Home network- Home network is a network within which device receives it’s identifying home address (IP address). Foreign network- Foreign network is a network within which mobile node operates when it is away from it’s home network. Care- of address- is network –native IP address of a mobile device. It is the IP address used to identify the device when it is operating in foreign network. It is used to identify the current location of a mobile node. Quiz 1. C A mobile node consists of two addresses. It has a home address which is permanent as well as a care- of address (CoA) which have been associated with network the mobile node intend to visit. There two kinds of entities that comprise Mobile IP implementation. Information concerning mobiles nodes whose home address is found in the home agent network are stored in a home agent while foreign agent is used to store information of mobile nodes who visit it’s network. At the same time foreign agents advertise care- of addresses aimed to be utilized by Mobile IP. Any node intending to communicate together with the mobile node utilizes the permanent home address of mobile node as a destination address to forward packets to it. Since home address logically belong to network linked with home agent, the normal IP routing mechanism forward those packets to home agent. Instead of routing those packets toward foreign agent via IP tunnel it encapsulates the datagram giving it a new IP header guided by address of mobile node. As a transmitter mobile node route packets directly to other node via foreign agent, avoiding sending packets via home agent. it use its permanent home address as source address for the IP packet ( triangular routing ). If needed foreign agent can apply reverse tunneling by tunneling the mobile node packets to home agent which in turn route packet to communicating node. Quiz 1.d Triangular routing, this is a routing where packet are first send to a proxy system way before been transmitted to the targeted destination. It is not convenient to use triangular routing in mobile IP you are most likely to face so many problems, however triangular routing fit well in some networking scenarios. In mobile IP packets to be sent to mobile node are routed first to home subnet of a mobile node’s, and finally forwarded by home agent to mobile node in it’s current position. But packets sent from mobile node are handled differently, they are sent straight to their destination. These way problems are likely to arise especially in usage of services that require ingress filtering, because source address on the packet is mobile node home address not care- of address which is assigned to node of it’s guest network. To solve this problem many implementations of Mobile IP provide options of tunneling packets from mobile node via home agent. Quiz 2. A Ad-hoc systems are characterized by lack of infrastructure as well as centralized control. While fore going properties ensure easy deployment, the radio propagation conditions of ad-hoc networks are more unpredictable than in planned and systematically laid-out cellular networks. Because of this difficulty to anticipate the channel conditions, approaches that have successfully been used to optimize the overall radio network performance of cellular systems cannot simply be applied to ad-hoc systems. Instead, these optimization approaches have to be evaluated carefully for their applicability in ad-hoc environments. There several emergent properties of ad-hoc networks which include key connectivity, node replica detection and trust establishment. There are also security emergent properties, which include like that of new threat model where the adversary adaptively compromise nodes of network. Quiz 2. B, i The Ad hoc On-Demand Distance Vector (AODV) algorithms enable self -starting, dynamic, multi hop routing between all mobile Nodes intending to establish as well as maintain ad hoc network. Mobile nodes are allowed to quickly obtain routes for new destinations and AODV does not demand mobile nodes to keep routes to those inactive communication destinations. AODV allows mobile nodes to respond to link breakages and changes in network topology in a timely manner. The operation of AODV is loop-free, and by avoiding the Bellman-Ford "counting to infinity" problem offers quick convergence when the ad hoc network topology changes. When links break, AODV causes the affected set of nodes to be notified so that they are able to invalidate the routes using the lost link.The AODV Routing protocol uses on-demand approach to finds routes, that implies, a route can be only be established when source node require it for data packets transmission. A destination sequence numbers is employed to identify most recent path. The difference between Dynamic Source Routing (DSR) and AODV is DSR utilize source routing in which a data packet carries the complete path to be traversed. However, in AODV, the source node and the intermediate nodes store the next-hop information corresponding to each flow for data packet transmission. In an on-demand routing protocol, the source node floods the Route Request packet in the network when a route is not available for the desired destination. Quiz 3. A Piconet - is a network where devices are connected in ad hoc style. Blue-tooth technology is used to implement the network. Minimum of two devices are used to form this network. The network is formed when a PC computer as well as cellular phone gets connected. A piconet can accommodate up to eight different devices where one act like a master and others as slaves. Scatternet - is groups of non –synchronized as well as independent piconets who shares minimum one common blue-tooth device. Blue-tooth devices are supposed to have point- to –multipoint capability to be involved in scatter net communication. Quiz 3. B The Bluetooth communication in a piconet network is based in master /slave operational mode. In a piconet up to 10 piconet can coexist without interference within a same coverage area. The blue tooth synchronously connect from one slave at time thus ensuring that no interference. One way blue-tooth devices does to avoid interference of one piconet with the other is it send weak signals of 1 milliwatt while a powerful phone is capable of sending 3 milliwatt signal. The lower power limit of blue-tooth devices is about 10 meters (32 feet) thus it cut the chance of interference between computer system and portable telephone plus television in the same room. It also utilize the technique of spread –spectrum frequency hopping that make it rare for more than one devices in a piconet to be transmitting on same frequency at same time. Quiz 3. C The effective bandwidth is lowered by the distance between the slaves and the master plus the physical area. Quiz 3. D To establish a connection to a piconet a device follows complicated procedure to ensure security thus it take several seconds to connect. Normally blue-tooth device operates in passive mode meaning it is listening to device trying to connect. Establishing connection start in inquiry phase where master device send inquiry request to devices trying to connect this access point. The device receive request and it reply. The master give it choose address and synchronise it with access point using a technique called paging. Paging involves synchronizing master clock and frequency with access point. A link with access point is established this allow master to enter service discovery stage it use service discovery protocol (SDP). Finally master device establish a connection with the device it create a communication channel using protocol L2CAP with access point. Quiz 4. A A have done a shooting game for android Mobile internet devices. Game player use shooting arrows to shoot on to flying birds images that emerge in all direction on the mobile screen. It needs a lot of concentration to aim and shoot the bird. The game duration is two minutes. You are required to shoot least ten birds for the first two minute failure to shoot minimum ten birds the game end. The minimum requirement of bird to shoot increase on step of five within the duration of two minute until the time the player will fail to meet the minimum requirement and the game end. Programming for Mobile internet devices is cumbersome since MID have limited resources as well as computing power as opposed to PCs. Quiz 4. B Programming for desktop and laptops is quite fun, and with relative ease. They provide supportive resources on which the end application will run on. For any application to run well in the targeted device, the device must meet minimum system requirement like memory size, processor speed, storage size, screen size and many more. Game application for instance require addition powerful graphic card. To develop a mobile application one face the problem of resources ranging from unlimited storage size, memory size, processor speed to screen size. Mobile have to be installed with specialized browser to view same web application with is previewed by normal standard browser on a desktop. So the large the screen size, processor, memory and storage the more developing environment became friendly and enjoyable. Quiz 4. C On mobile screen we get list of command button like menu list we have Back, Cancel, Exit, Help. Item, Ok, Screen, Stop. This is a friendly user interface implemented for mobile user to be able to interact with the mobile and be able to use it. The interface is implemented by the programmers as code and installed in a mobile so the mobile user are only required to press the button and J2ME codes installed on the mobile respond to the command. By pressing the button for instance cancel button on the screen menu you trigger an event that part of code associated with that cancel press button will execute. Within a fraction of a second cancel action will be implemented by J2ME and all the user see is screen responding. F21mc1 1a i) Slow-start of TCP/IP make it hard for mobile phone to connect with the internet. There always time out. (ii) . Information concerning mobiles nodes whose home address is found in the home agent network are stored in a home agent while foreign agent is used to store information of mobile nodes who visit it’s network. At the same time foreign agents advertise care- of addresses aimed to be utilized by Mobile IP. (iii) Triangular routing, this is a routing where packet are first send to a proxy system way before been transmitted to the targeted destination. These way problems are likely to arise especially in usage of services that require ingress filtering. To solve this problem by binding caches which enable many implementations of Mobile IP provide options of tunneling packets from mobile node via home agent. b) i)Bluetooth have relatively low freedom of interference from other network in the same area than 802.11thus it form ad hoc network. (ii) 802.11 have big bandwidth thus it have a wide range than Bluetooth. iii) Bluetooth is able to network large computers than 802.11 even if it cover small area range. c) For security reason it take several seconds before Bluetooth connect with the devices. There several authentication steps to be followed before connection is established. 2. a)The traditional routing algorithms would not allow self –starting, dynamism and multihop routing between all mobile nodes in ad hoc network thus making them undesirable. b) Mobile nodes are allowed to quickly obtain routes for new destinations and AODV does not demand mobile nodes to keep routes to those inactive communication destinations. AODV allows mobile nodes to respond to link breakages and changes in network topology in a timely manner. The operation of AODV is loop-free, and by avoiding the Bellman-Ford "counting to infinity" problem offers quick convergence when the ad hoc network topology changes. When links break, AODV causes the affected set of nodes to be notified so that they are able to invalidate the routes using the lost link.The AODV Routing protocol uses on-demand approach to finds routes, that implies, a route can be only be established when source node require it for data packets transmission. A destination sequence numbers is employed to identify most recent path. The difference between Dynamic Source Routing (DSR) and AODV is DSR utilize source routing in which a data packet carries the complete path to be traversed. However, in AODV, the source node and the intermediate nodes store the next-hop information corresponding to each flow for data packet transmission. In an on-demand routing protocol, the source node floods the Route Request packet in the network when a route is not available for the desired destination. 3 a) mobile devices have limitation in hardware capability that is low memory, low processor, and small display screen. Limitation in operating system does not support many features. b) Program designed for mobile devices are event driven thus making state charts to be more useful UML construct. State charts clearly define the state (event) in a clear graphical representation thus programmer can easily follow them when coding. 4 i) J2ME excluded AWT or Swing in it GUI operations which led to following advantages it eliminated the need to have java2 or separate JAR file when you are programming while swing is slower when programming because all component are drawn. J2ME developer miss the following: swing could provide extra component like Icons components, decorative borders component and tooltips component. ii) HTTP protocol is more reliable and faster in transferring large file over the internet as opposed to other protocol. ii) Touch screen would be appropriate to enter dimension and description of each room. iv) HTTP session will be used to upload the data to the office system where the client (PDA) will initiates request. A connection will be established through TCP to a particular port on host (Office system). The PDA will be listening through that port for a request and then start uploading the data. d) The image will be encoded as MPEG and then compressed to be able to be transferred over the internet. Read More