Network Security - Desklib

This document discusses the Data Link Layer, Transport Layer, Cloud Computing, and Mobile Computing in Network Security. It explains the role of the data link layer, network interface card, transport layer, TCP, UDP, cloud computing, and mobile computing. It also mentions the advantages and challenges of cloud computing and the evaluation of the spectrum in mobile computing.

Running head: NETWORK SECURITY
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Name of the Student:
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Author Note:

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Week 4:
The main objective of the data link layer is to make the communication between the
devices in the local network. Sometimes data link layer also works as hop to hop
communication. It works as the interface between the network layer and physical network.
There are two parts of data link layer- logical link layer and media access control. The
main objective of logical link layer is to work as an interface with upper layer (Shang yet
al.,2016). While the media access control sends traffic to network media and receive traffic from
network media.
In this context the role of network interface card is needed to be mentioned. It provides
the connection to network. Network interface card has multiple MAC address which is 48 bit and
unique. MAC address is provided by the manufacturer (Fiandrino et al.,2017).MAC address has
two parts- Organization unique identifier and unique 24 bit number.
Network card inspects all the packets on the local network. The packets for the particular
machines are received and other packets are discarded. The filtering process of the network
interface card reduces process of the host machine hence it enhances the performance (Zuo et
al.,2015). Through the cyclic redundancy check NIC also checks for the errors. The broadcasting
address in the data link layer follows certain protocols like CSMA/CD protocol or CSMA/CA
protocol.
Week 6:
The main objective of the transport layer is to port address for the individual application
session. Some ports are used for the server application. Other ports are used for the client
sessions. TCP segment and UDP diagram is used for the transportation layer. The transport layer

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ensures that each of the application is having the access to the network and all the applications
can be distinguishable from each other.
The transport layer breaks the large block of data into smaller chunks of manageable
segments so that the network layer can handle them and all the application can get access to the
network. At the destination , all the segmented data are reassembled by the transport layer in
order to get the original format. The transport layer assigns individual port number for each of
the applications.
For the network application the basic transport service can be provided by the UDP. The
source and the destination port number is mentioned in this format. However, no checking of the
packets arrived is done in this format. It is also called a stateless protocol (Deering & Hinden,
2017). The reason for mentioning this protocol as stateless protocol is that in this protocol each
of the request is treated as independent transaction which is not related to the previous request. It
consists of independent pairs of requests and responses.
Another way through which the transport layer services can be done is Transmission
Control Protocol. TCP can be regarded as the connection oriented protocol. The connection that
can be made through it is reliable and delivery of the data can be done from sender to receiver
(Muñoz et al.,2015). Before sending the data to the between the sender and receiver, the
connection is needed to be made. Sequence numbers are used throughout the connection for the
transfer of the data. TCP is a slower protocol compared to the UDP as it shares the
acknowledgement for the establishment of the connection.
Timers in the TCP are indulged to find out the lost transport layer segment. Sender sets
the timer and if the acknowledgement has not been received in time the pack is assumed to be

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lost . In this case, the pack has to be resent. The functions of the TCP segment is determined by
the TCP flags. The connection in the TCP can be established through three way handshakes. The
first step is to establish the connection between two ends. After that the initial sequence number
is established between the client and the server. The last step involves establishment of different
ISN number for the opposite direction.
The synchronization of data flow between the sender and receiver can be managed
through the TCP flow control. It is the responsibility of the TCP header to control the flow of the
data. Sliding window flow control can be done in this case.
Week 9:
Cloud is the mechanism that helps to store and manage the data online. The service for
the cloud storage device is provided by different cloud vendors (Gai et al.,2016)). The name of
some of the cloud vendors are- Google Drive, icloud by Apple. In most of the cloud storage large
amount for the free storage of data is provided. Apart from that the storage of data can be done
on the subscription basis. From the cloud storage the data can be stored, shared and managed.
The discussion is done about the Fed Uni cloud service. Fed Uni has hundreds of services
running on local cloud servers. Microsoft Azure is used in the cloud service of Fed Uni.
Workstation management, identification of the management is done through this service.
Some of the advantages of the cloud computing are it provides infinite resources, mitigate
the stress of managing the data for the technical staffs and it also provides the facility of
visualization. However, there are certain challenges of the cloud computing (Tong, Li &
Gao,2016). The implementation of the cloud computing is expensive and the cost is dependent
on the infrastructure.

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Another technology that has been discussed in this context is the mobile computing. The use of
the advanced mobile technology through the advanced spectrum is helping the progress in many
sectors. The evaluation of the spectrum in the mobile is evaluated from the 2G to 5G (Chen et
al.,2015). However, 5G technology is under the research and is not used commercially yet.
The transition of the mobile phone is controlled by the mobile switching center. Apart
from that it also manages the interface between the internet and public telephone network. The
base station communications with the handset on the basis of the technology used. For division
of the bandwidth different technologies like FDMA,TDMA and CDMA are used.

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References
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mobile cloud computing model for green computing. Journal of Network and Computer
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Chen, M., Zhang, Y., Li, Y., Mao, S., & Leung, V. C. (2015). EMC: Emotion-aware mobile
cloud computing in 5G. IEEE Network, 29(2), 32-38.
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April). Named data networking of things. In Internet-of-Things Design and
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Deering, S., & Hinden, R. (2017). Internet protocol, version 6 (IPv6) specification (No. RFC
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Zuo, J., Dong, C., Ng, S. X., Yang, L. L., & Hanzo, L. (2015). Cross-layer aided energy-efficient
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