a) IP address and a port address
IP address is an address computing devices use to identify itself and communicate with other devices. An IP address comprises a network identifier component and a host identifier component and due to it a correct delivery of the packet is achieved. IP address is connected with layer 3 and that is the internet layer. It governs the transmission of packets across an internet by sending them through several routers along the route. It also governs packet organization, timing constraints, and reliability.Port Address is the port number is used to identify the identity of the application sending the communication. Port address is also used to identify the identity of the application receiving the communication. Ports are very important for IS security and are connected with layers 4 and 5. Layer 4 governs the transmission across an internet and regulates aspects of end-to-end communication between two end hosts. Layer 5 secures interoperability of application programs and governs the applications work with each other.
The general packet structure can be presented in the following way:
b) The ‘quality of service’ parameters include availability, authenticity, confidentiality and integrity.
Availability means that authorized users have access to the information in the required format without obstructions and interferences. Example: I work as a freelancer on the specialized site. The information about the orders is available only to registered users. In order to get this information I need to be authorized by the website with username and password. Once I do it I can view all the information in the useable format and in the familiar language. Authenticity means that users have access to original information. It means that this information is not fabricated or reproduced from other sources. This parameter is often violated by phishing website gathering private information about users. Example: While searching for bank products I opened the site which copied the original information of Piraeus Bank and only minor differences in design indicated that this site was not an original one. Confidentiality means that all private information of users is kept in secret and only those who have authorities and rights can have access to this information. Example: while using shopping websites the clients insert their emails, numbers of their credits cards, telephone numbers and other information. This information should be available only to the administrators of the site and not to other users. Integrity means that the information is complete and uncorrupted. This parameter may be violated when a virus corrupts sent or received files. Example: while installing a program for reading online books I noticed that the installation file had a strange additional file which can potentially breach the integrity parameter. Non-repudiation means that transferred information has been successfully sent and received by the parties participating in this process. It also means that neither a sender nor a recipient can deny their getting the information or a message. Example: Before buying something online clients often ask for …