Network Security Requirements 3
Network Security Algorithms 6
Cryptography Applications 8
E-Mail Security 11
Wireless Networking Protocols 12
Network Security Requirements
The OSI (Open Systems Interconnection) Reference Model consists of seven layers and provides a conceptual framework which determines how network aware devices interact and communicate with each other, (Briscoe, 2000). Actual communications is distinguished by several network protocols, which is an established procedure and format that two data communication devices must recognize, acknowledge and utilize to be able to talk to each other, (Whitman, M., 2003). This section of the document explains the OSI layers and some of the devices and protocols operating within them. Application Layer 7 - defines the interfaces for communication and data transfer.
This layer also provides and support services such as job transfer, handles network access, e-mail, supports user applications and error recovery, (Tomsho, et al, 2007). Presentation Layer 6 - presents the data into a uniform format and masks the difference of data format between two dissimilar systems. It also translates the data from application to the network format. Presentation layer is also responsible for the protocol conversion, encryption, decryption and data compression. The Presentation layer is a best layer for cryptography, (Whitman, M. 2003). Session Layer 5 - establishes and manages the session between the two users at different ends in a network. Session layer also manages who can transfer the data in a certain amount of time and for how long. The examples of session layers and the interactive logins and file transfer sessions. Session layer reconnect the session if it disconnects. It also reports and logs and upper layer errors, (Whitman, M. 2003). Transport Layer 4 - manages end to end message delivery in a network and also provides the error checking and hence guarantees that no duplication or errors are occurring in the data transfers across the network. Transport layer also provides the acknowledgement of the successful data transmission and retransmits the data if no error free data was transferred. It also provides and error handling and connectionless oriented data deliver in the network, (Tomsho, et al, 2007). Network Layer 3 - determines how data transmits between the network devices. It also translates the logical address into the physical address, i.e., computer name into MAC address. It is also responsible for defining the route, managing the network problems and addressing. Routers works on the network layer and if a sending device does not break the data into the similar packets as the receiving device then the Network layer splits the data into smaller units and at the receiving end the Network layer reassembles the data, (Tomsho, et al, 2007). The Network layer routes the packets according to the unique network addresses. A Router works as the post office and network layer stamps the letters (data) for the specific destinations, (www.howstuffworks, 2003). Data Link Layer 2 - Data Link layer defines procedures for operating the communication links amongst Frames packets. It also detects and corrects packets and transmission errors. Bridges, switches, ISDN routers, intelligent hubs, and network interface cards operate at this level, (Whitman, 2010). Physical Layer 1 - defines the cables, network cards and physical aspects. It delineates the raw bit stream on the physical media. It also provides the interface between network and network communication devices. It is also responsible for how many volts for 0 and how many for 1. The Physical layer also verifies the number of bits transmitted per second and bi-directional or one way transmission. The Physical layer also negotiates the optical, mechanical and electrical features, (Tomsho, et al, 2007). An immediate and obvious difference between the OSI Model and TCP/IP is that…