ITECH1102 Networking And Security 4

ITECH1102 Networking And Security 4

ITECH1102 Networking And Security 4


You are required to analyse three topics:

1. Data Link Layer

2. Transport Layer

3. Cloud Computing

Application layer programs are able to interact by virtue of computer networks.


This assignment has three major aims:

  • To encourage students to use content analysis summaries to prepare for tests, examinations and to help their understanding of theoretical concepts.
  • To encourage students to conduct independent investigation into networking related topics from books, the Internet and through practical investigation.

Learning Outcomes:

  • Describe and explain the role and function of network connectivity in current computing.
  • Describe and explain the principles of communication in networks.
  • Describe the role and functionality of hardware and software entities that contribute to network communications.
  • Describe and explain the protocols and interactions that implement network communications.
  • Describe fundamental aspects of cloud computing.
  • Apply networking architecture knowledge to analyze the networking needs for business.


Data Link Layer

Data link layer offer various functions as it provides service interface for moving data from physical link layer to other. It is the third layer of the OSI model. OSI model has 7 layers that s physical, data link, network, transport, application, session and presentation layer. Theses layer offer the idealized network communication protocols. ITECH1102 Networking And Security 4

The information is encoded and decoded on the data link layer before transmitting it over the network. It also determines ways in which devices can be recovered from the corrosion of sending the frames at the same time. The data link layer has two sub layers one is logical link layer and other is media access control layer. The role of logical layer is to have a control of flow of data s that errors could be acknowledged.

The main functions of data link layers are that it ensures flow of data by sending and receiving devices easily. It also helps in handling the problems that occur at time of transmission of information. It also transmits information by easily routing the data packets and addressing it.

Once the connection is set up it is the responsibility of data link layer to divide the packets into data frames so that it can be handled by acknowledging it. The incoming data is analysed by checking specific bits. If there is a bug in the data link layer it notifies at the high level protocol. The data link layer manages the flow of information by enabling devices so that congestion can be controlled. It is one of the most complicated layers in the complete OSI model. It hides the detail about the data frames so that chances of collision reduce  (Ma, Huang,  Wen, Green & Ho?Baillie, 2016)

It is responsible for converting data stream of signal so that it could be sent over underlying hardware. Data link layers convers the information into a format so that it can be transmitted to upper layer. The data is stored in electric form it is converted to maintaining secure connection over the host.

The major functions of data link layer are discussed below:

The first is data framing that takes packet from network layer and encapsulates into the fame and then sends over the network bit by bit. Later at the receiver end, the signals are assembled into frames (Zhao, Sexton, Park, Baure,  Nino & So, 2015). The other function is addressing that make sure that hardware is addressed by unique function. The data frames are then sent on the network and it is synchronized between the sender and receiver. The other function is maintaining flow control between the networks that have different speed and capacity. It also offers multi access so that capabilities can be accessed easily by multiple systems.

The main task of the data link layer is to transfer raw material by adding checksum so that errors could be detected. The data are broken into frames and it is sent sequentially is that reliable connection takes place (Olivieri, et. al, 2016). The receiver sends back the acknowledgment frame to inform that information is received correctly. ITECH1102 Networking And Security 4

There are various design issues faced by data link layer, one is keeping the transmission fast over the network as the speed of receiver slows down speed of transmission of data. Thus a traffic regulation mechanism is needed so that transmission is buffered and error is handled carefully. The other issues are broadcasting as it requires control over the shared channel. Data link layer deals with such issue.

It sends the data in concept of framing by establishing a point to point connection between computers by sending data into stream of bits (Xu, Li, Li, Zhang & Muntean, 2015)

Data link layer supports the communication between devices over the same network or different. It assures that every piece of information is secure and it is not leaked to any unauthorised user. It offers reliable communication as data is encoded and access is offered only by authorised user. The main function is physical addressing and access control that makes sure that safe transfer takes place. The gap between transmission of data packet is checked and it is assured that synchronization is maintained. It keeps the bit buffered so that smooth transaction takes place (Xu, Li, Li, Zhang & Muntean, 2015)

Data link layer adds physical addresses of both source and destination machines.

Various issues are framed at time of framing one is detecting the station of frame so that alerts can be created. It also becomes detecting the end frame this for this an ending bit is created (Lopacinski, Nolte, Buechner, Brzozowski & Kraemer, 2015). The starting bit also needs to be identified so that a sequential patter can be maintained while delivering the information.

It is the lowest layer of the OSI model that transmits the bit over the network. It sends the complete information about the data that is size of the packet, its address, and the destination address. It offers error handling capacity by detecting the bugs so that security is maintained. It provides the transfer across physical link layer. It offers local delivery of frames from one node to another. Some of the design issues of data link layers are sservices provided to the Network Layer, framing, error Control and flow Control. The major function of data link layers is dealing with transmission errors, regulating data flow and slow receivers not swamped by fast senders. It also offers a well-defined service edge on the network by taking care of all the transmission errors. This responsibility of data link layer is packing the data by encapsulating it into the frames. It also assures that synchronization of data is maintained at time of data transfer. It ensures flow control by exchanging the information at high speed.

Transport Layer

As based upon open system interconnection (OSI), the transport layer is responsible for end-to-end communication over an interconnected network. On different hosts, there is a logical communication between application processes within a set of protocols including various components over the network.

It also helps the management in rectification of errors and thus delivers reliability and quality to the end user. With the help of the transport layer, one can receive or send error corrected data with the help of a host and also enable network components to allow multiplexing. In Open System Interconnection Model, transport layer is considered to be fourth layer of this network structure (Agyapong et al, 2014).

Transport layer also helps management by differentiating the applications function on the same machine or computer device. The effective goal of transport layer is to help end user by delivering cost effective and reliable services. It works transparently within the layers above to deliver and receive data without errors. The application messages break into segments and transfer them to the network layer and this is done on the send side. Furthermore, on the receiving side, segments are reassembled into messages and these are passes to application layer. One of the major advantages of TCP is that it uses a positive acknowledgement with retransmission methodology where the receiving device needs to respond back to the sender that it certainly accept the data it was sent (Rathnayaka & Potdar, 2013). If this acknowledgment message not received by the sender, an assumption is being made that receiving device did not receive a part or all of transmission. It also offers major services like-

  • Data flow in the same order and also no loss of packets done in the transport layer due to an attribute of checksum.
  • A connection oriented communication is offered by transport layer with help of various protocols such as internet protocol, user datagram protocol, etc.
  • In transport layer, the congestion is also dodged by enabling the traffic over the telecommunication network and thus allow to deliver the data to an appropriate place over the host.
  • Various different process completed on transport layer such as multiplexing of data, adding of source ad destination port number in header and also identify the address of the hosts.
  • Some applications try to receive byte streams instead of packets; transport layer enables for the transmission of byte-oriented data streams if necessary. It is called as byte orientation.

The two key protocol that is used by transport layer includes a transmission control protocol, user diagram protocol that offers a consistent communication among hosts. There is end-to-end communication in a transport layer that helps in delivering of data without any error (Gringeri, Bitar & Xia, 2013).

Transport layer in networking is based on a layered architecture model that provides host to host communication services for applications. A logical communication is managed through this layer which ensures not issue in protocols. Between source machine and destination machine, transport layer provides connection less and connection oriented transmission (Sun et al, 2011).

With help of Advantage Database Server using either datagram or streaming paradigms, the advantage client can communicate.

ITECH1102 Networking And Security 4