COIT20261 Network Routing and Switching: Written Assessment 2

Desklib provides past papers and solved assignments for students. Access this solved COIT20261 assignment now!

COIT20261 Network Routing and Switching (Term 3, 2018)
Assignment item —Written Assessment-2
Do not use quotations from your referenced sources in your answers, simply write explanations
in your own words to convey the concept. Serious penalties and mark deductions may apply for
non-compliance.
Write your answers in the template provided on the next page.

COIT20261 Network Routing and Switching (Term 3, 2018)
Assignment item —Written Assessment-2
First Name:_________________________ Last Name:____________________________
Student ID: __________________________
Question Number Mark
allocated
Marks
earned
Question 1: (10 marks)
1.
2.
3.
4.
5.
6.
7.
8.
The next-hop address will be 130.24.10.15
R4 will choose m2 interface.
There will be 2 hops.
It will drop the packet and ping will be unsuccessful
R4 will use port m0 for destination address of 210.20.40.126/21
The next-hop address will be180.0.0.4/8
133.0.10.0/24
Routing table of router R3:
Prefix Network address Next-hop address Interface
/16 130.24.0.0 180.20.0.30/8 m0
/24 230.10.50.0 Directly connected m1
1-7 1
mark
each, q.8
3 marks
Question 2: (5 marks)
a) Router received the 5000 bytes long packet with no option. The router
will create the four segments of it as the maximum MTU is 1500 bytes at
a time. Also, 20 bytes are reserved for IP header. So the fragments will
be:
Fragment 1 1480
Fragment 2 1480
Fragment 3 1480
Fragment 4 560
2.5
b) The fragment offset for each Original IP datagram is as follows:
Sequence Identifier Total length DF
My/Don’t’t
MF
Last/More
Fragment
offset
0 1 5000 0 0 0
Fragment Offset is multiple of 8 bytes
So, our 2nd fragment offset will be =185 (185*8=1480)
\
1.5

COIT20261 Network Routing and Switching (Term 3, 2018)
Assignment item —Written Assessment-2
IP Fragment
Sequence Identifier Total length DF
My/Don’t
MF
Last/More
Fragment
offset
0-0 1 1500 0 1 0
0-1 1 1500 0 1 185
0-3 1500 1500 0 1 370
0-4 1 500 0 0 250
c) The size of all fragments together will be greater than the initial datagram
size because of the additional 20bytes in each data fragment.
1
Question 3: (10 marks)
1. SDN (Software defined networking) is the new advancement in the field
of computer networking. SDN offers us a new improved, robust and
simplified mechanism for centralising our network management.
SDN offers so many new solutions for creating policy driven network
monitoring system. It is fast and one of the main features SDN provides
that it has separated the Control and Data plane due to which the changes
in our existing network architecture can be made easily and instantly.
Some of the benefits provided by SDN includes
Centralised network management: SDN is able to provide and create a
centralised view of our whole network which makes it easy to control.
The data and control plane are decoupled in SDN which becomes the
main reason for fast delivery of packets across the network.
SDN gives us some unique feature of experimenting with our pre-existing
network. It allows the administrators to change, update and create new
configuration to the network without actually impacting the network. The
physical and virtual devices both can be controlled by a single set of
APIs.
Using a SDN controller in our network management can also result in
building a low cost network management system. SDN offers more
responsiveness, agility and robustness in our network
3
2. The data plane, control plane and programmability are separated or
decoupled in SDN. In conventional networking whenever a problem
arises there is likely to be a protocol needed for its solution. It means the
data is always dependent that protocol and protocol defines how the data
will be processed.
An ideal architectural design of a SDN switching device consists of two
logical components the data plane and the control plane.
The packet forwarding is performed in the data plane with its processor. It
forwards the packets following the rules set by the control layer.
4

COIT20261 Network Routing and Switching (Term 3, 2018)
Assignment item —Written Assessment-2
The control plane consists controller which communicates with the
switching device to understand or receive the rules for packet forwarding
(at switching level) and the rules for link tuning (at data-link level).
SDN doesn’t follow the mechanism of conventional switching in which
routing and packet forwarding are dependent on protocols. This results the
SDN switching devices to only be responsible for forwarding data packets
and frees them from making control decisions.
3. OpenFlow(OF) is first defined standard for SDN.
In this standard, the description of communication between SDN
controller and forwarding plane of network devices such as Routers and
Switches (either physical or virtual) is given. It defined the
communication protocols for communication between the two entities.
This helps SDN controller which is often termed as the "brain" in SDN
environment in better adapting to the network changes.
In an OF environment, When a device want to communicate to an SDN
controller it follows or uses the OpenFlow protocol. This allows SDN
controller to push down changes to switch/router which then allows
network engineers to separate data and control plane and then they can
start experimenting without impacting the original network.
The OpenFlow standard introduces Programmability, Centralisation and
Abstraction in Software Defined Networking.
3
Total marks awarded 25 (max)
Less late penalties if applicable
Less plagiarism penalties if applicable
Total marks earned
Markers comments: