Academic Writing

Design and describe an application level protocol to be used between the mobile device and CoHo’s central server. Your protocol should allow the communication based on user’s id and password verification, query on menu availability, the order processing etc. Your protocol entities should be able to handle all-too-common cases like the invalid payment details, incorrect username/password etc. Specify your protocol by listing the message exchanges and the action taken by the mobile device or the server computer on transmission and receipt of messages. b. One of the vendors has proposed a reliable data transfer protocol that uses only negative acknowledgements. Some nodes on the network communicate frequently while few communicate rarely. Suppose the sender sends the data only infrequently. Would a NAK-only protocol be preferable to a protocol that uses ACKs? In case of frequent communication, would a NAK-only protocol be preferable to a protocol that uses ACKs? Evaluate both the recommendations based on the operation of NAK-only protocol. c. The following diagram indicates a part of the network. Letter 'A' indicates the CoHo server while 'G' indicates the mobile device. Letters from 'B' to 'F' indicate the intermediate routers on the network. The message containing the customer order must be transferred to the CoHO’s server with the shortest possible route on the network. Apply routing algorithm in order to determine the shortest route between the mobile device and the server. Justify your choice of the algorithm by comparing with other routing algorithms and demonstrate the shortest route between the mobile device and the server. d. Critically discuss the different types of cryptographic techniques, which could be implemented in order to achieve secure data communication. Analyse the type of cryptographic technique that should be adopted in order to achieve message integrity, confidentiality and user authentication over the network. e. Mobile application has been considered by CoHo to meet the requirements of today's competitive age. Present an analytical discussion based on 'possible security threats to mobile applications' to help the management in visualizing prospective security issues.