Essay Layering & Internet Model

1: Physical layer: The purpose of the physical layer is it deals with the hardware components, like cads and cables for sending and receiving data of a carrier.

Layer 1: Physical - This is the level of the actual hardware. It defines the physical characteristics of the network such as connections, voltage levels and timing.

The fifth layer is the session layer this establishes a connection,this layer makes and sets up the connection using co ordinates and could terminate conversations links. the session layer produces services that make authentication after an interruption and not only that but it can reconnect.and as well as the transporting layer it can also have the TCP and the UDP can provide services for all most all applications.An application layer is an abstraction layer that specifies the shared protocols and interface methods used by hosts in a communications network. The application layer abstraction is used in both of the standard models of computer networking; the Internet Protocol Suite (TCP/IP) and the Open Systems Interconnection model (OSI model).Although both models use the same term for their respective highest level layer, the detailed definitions and purposes are different.In TCP/IP, the application layer contains the communications protocols and interface methods used in process-to-process communications

• “Application - The Application Layer is the layer that most network users are exposed to, and is the level at which human communication happens. HTTP, FTP, and SMTP are examples of the application layer protocols the Patton-Fuller will now be utilizing for communicating electronically” (Network Design, 2012).

1. Application (in terms of cabling infrastructure): The application layer is the OSI layer closest to the end user, which means both the OSI application layer and the user interact directly with the software application. When determining resource availability, the application layer must decide whether sufficient network or the requested communication exists.. (OSI_model#Layer_7:_application_layer)

This makes sure the data transferred is in the right order, error free and reliable from beginning to end. The Network Layer is the third layer of the model and its function is to interpret the network addresses into physical addresses and figure out how to direct them from the sender to the receiver. The next layer is the Data Link Layer, this is the second layer and it separates the data it receives from the Network layer into specific frames so they can be transmitted by the Physical layer. Frames are packages for moving data, they include the raw data, the sender and receiver’s addresses, as well as error checking and control information. This makes sure the frames are delivered to their destination without any problems. The physical layer is the first layer and the lowest, the protocols at this layer recognize and receive the frames from the Data Link layer. They also monitor data error and set data transmission

The OSI Model is a model is used to define how data is theoretically passed on a network. Each layer is responsible and has its own duties for a network. The name of layer 3 in the OSI is the Network Layer. This layer is responsible for creating the paths for the transmission of data across the network. This layer provides routing and switching capabilities, as well as, internetworking, congestion control, and packet sequencing (Beal, 1999).

The Application layer within the OSI reference model is where the application and the user communicates. In other words, the application layer is the ending of data that is transferred in visual form to the user. This layer provides the interface between the applications we use to communicate and the underlying network over which our messages are transmitted. The Application Layer functions are to provide the interface for application-specific protocols commonly used such as HyperText Transfer (HTTP), file transfer (FTP), Simple mail transfer (SMTP), Internet message Access (IMAP),

Layer 3 is the network layer and utilises multiple common protocols to perform routing on the network. Protocols consist of the Internet Protocol (IP), packet sniffing and DoS attacks such as Ping floods and ICMP attacks. Because of their layer 3 nature, these types of attacks can be performed remotely over the Internet while layer 2 attacks primarily come from the internal LAN.

The internet layer is built up of four core protocols: IP, IGMP, ICMP and ARP. Internet protocol (IP) is responsible for routing, IP addressing and breakdown/reassembly of data packets, address resolution protocol (ARP) is responsible for mapping an IP address to a device on the local network, internet control message protocol (ICMP) provides diagnostic information and error reports on lost packets, internet group management protocol (IGMP) controls who receives IP datagrams in a single transmission. The transport layer is built up of two core protocols: TCP and UDP. Transmission control protocol (TCP) sequences and acknowledges packets sent and their recovery when lost in transmission allowing the computer to make and maintain network conversations where applications exchange data, defined as a connection-oriented protocol meaning the connection is maintained until the programs has finished exchanging data. User datagram protocol (UDP) This is used to transfer small amounts of data when the use of error correction isn’t needed increasing the speed of the transmission, common in multi-player video games as the user will not need to receive packets of past events in the game so the error correction featured in (TCP) would be

6. Why is Ethernet technology more appealing to users than the rest of the LAN technologies?

In general, on the internet, every packet follows 5 layers of structures (Application, Transport, Network, Data Link, and Physical). Since I have to talk about Connection-Oriented and Connectionless as a service, I will focus on the Transport layer because they are part of this layer. It allows multiple applications to use one network connection simultaneously, the layer will create ports on your computer allowing them to be reserved and used by the Application layer. Let's say that port 3600 will be used to send a message to port 80 of some other computer, whenever the port is ready to send a message, it passed on to Transport layer. In this layer, it wraps the message inside the Segment which contains some additional

Layer 4 which is the Transport layer responsible for end to end connection. It parts and collect the data and is made into data streams. It ensures that the data is established and maintained. It also detects any errors found in the data while transferring as well as recovering those

The two authors follow the story from the conception of the idea of "packet switching" in the early 1960s to the creation and development of the Internet. We see how one idea led to another and how the intelligent people around the circumstances influenced the developments.

The transport layer: This layer determines how the packets are transported such as the order and what to do if there are errors. The purpose of this layer is to make sure the data be transported correctly. Besides, due to the limitation of physic (maximum IP packet size is 65535bits), the speed of transportation is limited. As a result, this layer needs break big data in to small packets. This can also collect small data into a big packet to reduce unnecessary transmission, which can improve the transmitting speed. Example protocols are TCP, UDP, SCTP.