What is a Network Router? Routing Terms

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
ANSWER TEMPLATE ASSIGNMENT TWO
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Questions Mark
allocated
Mark
earned
Question 1: (10 marks) 5 each
table
Answer: Routing table of router R3:
Mask Network address Next-hop address Interface
/24 230.10.50.24 …. m1
/24 133.0.10.12 180.0.0.4 m2
/21 210.20.40.2 180.0.0.4 m2
/18 170.16.64.0 180.20.0.30 m0
/16 130.24.10.16 180.20.0.30 m0
/0 0.0.0.0 180.0.10.10 m1
Routing table of router R4:
Mask Network address Next-hop address Interface
/24 230.10.50.24 180.0.0.10 m0
/24 133.0.10.12 …. m1
/21 210.20.40.2 …. m0
/18 170.16.64.0 180.20.0.30 m0
/16 130.24.10.16 180.20.0.30 m0
/0 0.0.0.0 180.0.10.10 m1
5 max
5 max
Question 2: (5 marks)
a) IP datagram packet size= 5,500 bytes containing header, MTU=1500, 2.5 max

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
number of packets=4.
Let us assume the header= 20 bytes.
Size of data included in original packet= (5500-20) = 5480.
Size of first 3 fragments from original packet= size of MTU= 1500.
Size of last fragment= 5500-(1500+1500+1500) = 1000.
Size of Fragment 1= 1500 including the header=
(1500-20) = 1480. Hence the starting byte= 0 and the ending byte=
1479.
Size of Fragment 2= 1500 including the header= (1500-20) = 1480.
Hence, the starting byte= 1480 and the ending byte= 2959.
Size of Fragment 3= 1500 including the header= (1500-20) 1480.
Hence, the starting byte= 2960 and the ending byte= 4439.
Therefore, data part of Fragment 4= (5480-4440) = 1040.
Full fragment size of last packet= 1040+20= 1060. Hence, the starting
byte= 4440 and the ending byte= 5479.
b) Fragment offset= (1500-20)/8= 185.
Fragment offset for the last fragment= (1060-20)/8= 130.
Fragment offset for Fragment 1= 0.
Fragment offset for Fragment 2= 185.
Fragment offset for Fragment 3= (185+185) = 370.
Fragment offset for Fragment 4= (370+130) = 500.
1.5 max
c) Total size of the 4 fragments= (1500+1500+1500+1060) = 5560. Here it
is visible that the total size of the four fragments is larger than the
original sized datagram. On the contrary, in the initial size of the
datagram there is only one size of header included that is 20 bytes.
However, in all of the fragments 20 bytes of the header is also included
that is standing out to be 80 bytes in total. On the contrary, one of the 20
bytes is already included in the original datagram. This leads to the fact
that one header of 20 bytes gets cancelled out by one of the fragments,
and hence three other header size of 20 bytes is getting added to 5500
amounting up to 5560.
1 max

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
Question 3: (10 marks)
a) Software-Defined Networking refers to the physically existing
separation belonging to the control plane in regards to the respective
network coming from that of the forwarding place as well as where the
controls meant for the control plane has the real time existence in
reference to the several existing devices (Tang et al., 2016). This
commonly refers to a rising architecture, which is specifically dynamic,
operable as well as cost-efficient. The salient features of the SDN
architecture within the field of networking are,
 Directly programmable- the control over the network has the
inclusion of a feature that allows to be directly programmable
because of the reason that it has to be specifically decoupled
from all of the functions in particular.
 Agile- abstraction of the control from the forwarding provisions
all the administrators with the allowance to adjust the traffic flow
across the network in a dynamic method for meeting the needs in
regards to changing (Bera, Misra & Vasilakos, 2017).
 Centrally managed- the network expertise that is centralized
completely based upon the software related to SDN controllers
that maintains a particular globalized view in relation to the
entire network. This specifically takes the form of the
applications as well as the policy engines in the form of a local
and a single switch.
 Configured with programs- SDN provisions the network
managers with the allowance to configure, secure, manage as
well as optimize the network and the relative resources in a quick
manner with the help of a dynamic as well as an automated SDN
program (Haque & Abu-Ghazaleh, 2016). This can be written by
them itself because of the fact that all such programs have no
dependency upon the software related to proprietary.
 Based upon open-standards as well as the vendor-neutral- during
the implementation with the help of open standards, the SDN
simplifies the design of the network as well as the relative
operations in accordance to the instructions placed forward by
the SDN controllers keeping aside the devices and the protocols
that are vendor-specific.
3 max

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
Figure-1: Software-Defined Networking.
(Source- )
b) In reference to the statement that has been mentioned stating that “SDN
allows network devices such as switches and routers to be responsible
only for forwarding data packets, and frees them from making control
decisions, e.g., packet forwarding rules”, the meaning has been stated
properly. The above states forward the meaning that direct packet
forwarding is only done by a controller (Rawat & Reddy, 2016). Within
the relative architecture of SDN, when the specific switch receives a
packet but is not able to find a perfect match to that within the flow
table, particularly the packet is forwarded to that of the controller that
decided on a particular basis what shall be done. Hence, the controller
decides about the packet and then forwards it to the sender switch to get
on with the further actions that are required in particular.
The architecture of Software-Defined networking specifically places a
separation between the control plane belonging to the router and on the
other hand from the data forwarding plane (Baktir, Ozgovde & Ersoy,
2017). The control plane takes all the necessary as well as the relative
decisions in regards to the procedure of routing with the help of the
4 max

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
router that is present within the respective network. With the help of the
SDN routing and the relative methods, the decisions are specifically
made instead of the individually existing routers within the network that
has been designed or undertaken. This is the primary procedure that is
followed by the SDN architecture while taking all the control decisions
regarding the entire network and the processes that gets carried out
within the network.
c) OpenFlow (OF) in common terms refers to one of the primary software-
defined networking (SDN) and relative standards (Karakus & Durresi,
2017). This originally puts forward the definition of the communication
protocol within the environment of SDN that specifically enables the
SDN controller to have a direct interaction with the forwarding place
belonging to the network devices like that of switches along with the
routers.
On the contrary, a controller of SDN within the field of SDN is referred
to the most important component of a SDN network. This relays the
information to all of the existing switches or the routers along with the
applications and that of the business logic. In reference to the recent
conditions, all of the organizations have been visibly identified to have
been deploying more number of SDN networks along with SDN
controllers that have been tasked by federating between the domains in
relation to the SDN controllers (Shu et al., 2016). This is achieved with
the help of using the common interfaces of the applications such as the
like of OpenFlow and that of open virtual switch database (OVSDB).
However, the SDN has a complete relevance with that of the OpenFlow
and has a specific functionality regarding the entire process. To carry out
the work in an OF environment, any of the existing device that carries a
specific desire to communicate with a SDN controller having the
importance of support from the OpenFlow protocol. With the hell of this
interface, the controller for the SDN brings in changes within the switch
or the router and the related flow-table provisioning the network
administrators with the allowance to separate the traffic and to control
the flows for an optimal performance (Ndiaye, Hancke & Abu-Mahfouz,
2017). This also has the inclusion of starting with the process of testing
newer configurations as well as the applications.
3 max
Total marks awarded 25 (max)
Less late penalties

COIT20261 Network Routing and Switching Term 3, 2019
Assignment item —Written Assessment-2
Less plagiarism penalties
Total marks earned
Markers comments:
References
Baktir, A. C., Ozgovde, A., & Ersoy, C. (2017). How can edge computing benefit from
software-defined networking: A survey, use cases, and future directions. IEEE
Communications Surveys & Tutorials, 19(4), 2359-2391.
Bera, S., Misra, S., & Vasilakos, A. V. (2017). Software-defined networking for internet
of things: A survey. IEEE Internet of Things Journal, 4(6), 1994-2008.
Haque, I. T., & Abu-Ghazaleh, N. (2016). Wireless software defined networking: A
survey and taxonomy. IEEE Communications Surveys & Tutorials, 18(4), 2713-
2737.
Karakus, M., & Durresi, A. (2017). A survey: Control plane scalability issues and
approaches in software-defined networking (SDN). Computer Networks, 112,
279-293.
Ndiaye, M., Hancke, G. P., & Abu-Mahfouz, A. M. (2017). Software defined networking
for improved wireless sensor network management: A survey. Sensors, 17(5),
1031.
Rawat, D. B., & Reddy, S. R. (2016). Software defined networking architecture, security
and energy efficiency: A survey. IEEE Communications Surveys &
Tutorials, 19(1), 325-346.
Shu, Z., Wan, J., Li, D., Lin, J., Vasilakos, A. V., & Imran, M. (2016). Security in software-
defined networking: Threats and countermeasures. Mobile Networks and
Applications, 21(5), 764-776.
Tang, T. A., Mhamdi, L., McLernon, D., Zaidi, S. A. R., & Ghogho, M. (2016, October).
Deep learning approach for network intrusion detection in software defined
networking. In 2016 International Conference on Wireless Networks and
Mobile Communications (WINCOM) (pp. 258-263). IEEE.