Terminal Communication Agent - Assignment Example

PAPER SOLUTION Question a Users on the move come across access point change when they move from one place to another. when a mobile enters new network Terminal Communication Agent (TCA) are informed about the new position .the care of address is used when a mobile is outside their parent cloud(foreign network).Further Mobile I.P specifies how a mobile node registers with its home agent Question 1 (b) IP in IP Tunneling are used to forward information between end points acting as a bridge between portion of an IP network that have different capabilities. A typical use of IP in IP tunneling is forwarding of IP multicast traffic from one area of intranet to another area of intranet, across the portion of intranet that does not support multicast forwarding or routing . After IP-in-IP interfaces are created and added as an IP routing interface, you must configure the tunnel endpoints. In other words it is used to make a tunnel between the two routers. IPIP tunneling protocol adds the Following possibilities to a network setups Tunneling of Intranets over the Internet Use it instead of using source routing Question 1 (c): IP in general stands for internet protocol and is a communication protocol for exchange of data. Two variants are, ipv4 and ipv6.they generally differ in addressing, routing, security and overhead Ipv4 Ipv6 Addresses are 32 bit in length Header includes checksum IPsec is optional Broadcasting of traffic Required to support a 576-byte packet size Addresses are 128 bit in length Header do not include checksum and are simplified IPSec enabled : which provides it end to end security Mobility Multicasting of traffic( that includes anycast traffic) Required to support 1280 byte packet size Question 2 (a) Adhoc networks are de-centralized in nature and do not have an existent infrastructure For adhoc networks adaptive routing strategies are followed .adhoc networks can be divided into three categories: Reactive/on demand: route is calculated only on demand .examples are LMR AND DSR Proactive/table drive: route is calculated in advance and information is periodically advertised. Examples are OLSR and GSR Hybrid: they are reactive and proactive at the same time .they try maintaining a balance between the two. Examples are DST and ZRP Question 2 (b): (1)The route is discovered through initiation of route discovery and broadcast of request and this is followed by accumulation of address of the devices between the source and destination. A flow id option is used to transfer packets on a hop to hop basis. Route Reply is used for confirmation. (ii) . Intermediate nodes use the source route included in a packet to determine where the packet needs to be forwarded. (iii). Route error packet is sent back to host and Route discovery is setup again through broadcast of route request. In case of route error, the hop in error is removed from the host’s route cache; an end to end and hop by hop acknowledgement can be adopted to avoid further loss in communication Question 3 (a) Hidden terminal is a phenomenon where the nodes are in non line of sight contact and are connected through an Access point .Its implications can be in form of packet loss, collision between them, decrease in overall throughput. It also results in difficulty in transmission at Data link layer where MAC is operational Questions 3 (b) CSMA/CD stands for Carrier Sense Multiple Access/Collision Detect and terminates the transmission as soon as collision is detected. CSMA/CA stands for Carrier Sense Multiple Access/Collision Avoidance and it monitors the activity before transmission and if channel is found busy, it delays sending packet to destination until vacant. Question 3 (c) In CSMA/CA as soon as the packet is received, the channel is checked for availability, if the channel is clear, node is sent to destination, otherwise, packet is kept in waiting for a duration that is termed as back off factor. As soon as vacant slot is traced, the packet is sent along the destination. When two devices try accessing the channel simultaneously, a set of rules are used for this purpose to determine the devices activities. CSMA/CA uses Broadcast technique to inform the neighboring nodes of its delivery. A back off counter is used to prevent the packet from transmission until vacant route is not available. Question 3 (d) The hidden node problem is solved in such a way that the node intending to send packet sends a Request to Send (RTS) first,and waits for reply in form of Clear to send(CTS),as long as the Clear signal is not received the frame is put in wait for certain amount of duration, hence the request and reply function helps avoiding collision between the two Question 4 (a) Difference between Java And C# C# Java -Windows specific language -Programs written in c# are usually run on windows -C# has got both constructors and destructors -C# can perform strict floating point evaluation in contrast to java -C# supports more features in terms of syntax -Complete backward compatible source code -A cross platform language -Programs written in java are executable on any operating systems -more mature in nature and existance -Java does not have destructors for release of all expensive resources -Java lacks variable type interference -Java lacks multi-dimensional arrays Question 4 (b) (i) The code that is managed in .NET framework is known as managed code,it is also defined as the code that targets run time is called a managed code,it is directly executable by CLR with help of managed code execution managed code uses CLR which in turn looks after the application and its memory ,security, and debugging. Question 4 (b) (ii) : Microsoft Intermediate Language Code is a CPU independent set of instructions, it includes instructions like loading, storing, initialization. When we compile it, it produces an executable and this executable contains two parts 1) A stub assembly language program for starting CLR complier 2) The MSIL code of compilation application The stub program then starts the CLR just in time complier that can run on the system. The run time supplies another mode of compilation called install time code generation which converts MSIL to native code just as the regular JIT complier Question 4 (c): The MIDlet design should be that the parking warden should have a camera phone, The MIDlet itself should have a OCR (Optical Character Recognition) Algorithm built in to recognize numbers, and should have access to GPRS/EDGE and/or GPS to co-ordinate street numbers in which the offence has taken place, after that the algorithm should combine the sensors and camera data to make an offender offence profile, which then can be emailed to the central office through GPRS/EDGE, and if the communication link or network is down ,.MIDlet must save the profile and mail it as soon the network connection is re-established. Read More