Networking Fundamentals: Subnetting Drills and Exercises

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ITEC647 Data Communications
Assignment 1, 2019

Part 1: Subnetting and the network layer
Question 1: Drills
a. what are the equivalent subnet masks in dotted-decimal notation for the following slash-
notation address blocks?
Sn.NO Slash Notation Dotted Decimal
i /23 255.255.254.0
ii /11 255.224.0.0
iii /29 255.255.255.248
iv /31 255.255.255.254
b. [6 marks] What is the maximum number of hosts that can be addressed on the following
networks?
Let’s assume that the IP address is 10.0.0.1
Sn.NO Slash Notation Dotted Decimal Available Range Max. host
i /19 255.255.248.0 10.0.0.1-
10.0.31.254
8190
ii /30 255.224.0.0 10.0.0.1-10.0.0.2 2
iii /23 255.255.254.0 10.0.0.1-
10.0.1.254
510
c. Are the following net masks legal? If so, what are their slash-notation forms? If not why
are they not legal?
Sn.NO Dotted Decimal Slash Notation Legal Comments
i 255.255.240.0 /20 Yes It can accommodate
4094 available hosts
ii 255.252.255.0 Cannot Defined NO This subnet is not
legal because next
octet can only get
filled when previous
octets gets filled
completely.
iii 255.192.0.0 /18 Yes No. of host it can
accommodate is
16382 (available)
iv 255.255.255.254 /31 NO Available host are
NIL in this notation.
Question 2: Subnetting Exercise
a. Create a Fixed Length Subnet Mask (FLSM) scheme so that each Faculty or associated
entity has a separate subnet.
Ans: Given IP address: 137.111.0.0/16. Let’s assume that we provide each OU with 4096 IP
addresses which represent in slash notations as /20 and remaining addresses are for future
department or OU’s Expansion. Let’s create a FSLM for each OU:

1. Faculty of Arts
Address: 137.111.0.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.0.0/20
Broadcast: 137.111.15.255
HostMin: 137.111.0.1
HostMax: 137.111.15.254
Hosts/Net: 4094
2. Macquarie Business School
Address: 137.111.16.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.16.0/20
Broadcast: 137.111.31.255
HostMin: 137.111.16.1
HostMax: 137.111.31.254
Hosts/Net: 4094
3. Faculty of Human Science
Address: 137.111.32.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.32.0/20
Broadcast: 137.111.47.255
HostMin: 137.111.32.1
HostMax: 137.111.47.254
Hosts/Net: 4094
4. Faculty of Medicine and Health Sciences
Address: 137.111.48.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.48.0/20
Broadcast: 137.111.63.255
HostMin: 137.111.48.1
HostMax: 137.111.63.254
Hosts/Net: 4094
5. Faculty of Science and Engineering
Address: 137.111.64.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.64.0/20
Broadcast: 137.111.79.255
HostMin: 137.111.64.1
HostMax: 137.111.79.254
Hosts/Net: 4094
6. Macquarie University International College
Address: 137.111.80.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.80.0/20
Broadcast: 137.111.95.255
HostMin: 137.111.80.1

HostMax: 137.111.95.254
Hosts/Net: 4094
7. Macquarie City Campus
Address: 137.111.96.0
Netmask: 255.255.240.0 = 20
Network Address: 137.111.96.0/20
Broadcast: 137.111.111.255
HostMin: 137.111.96.1
HostMax: 137.111.111.254
Hosts/Net: 4094
b.
Ans: Let assumes that each department allocate with 256 ip address and remaining are for future
expansion. Let create VLSM of Each Faculty OU in departments:
1. Faculty of ARTS:
Department 1:
Address: 137.111.0.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.0.0/24
Broadcast: 137.111.0.255
HostMin: 137.111.0.1
HostMax: 137.111.0.254
Hosts/Net: 254
Department 2:
Address: 137.111.1.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.1.0/24
Broadcast: 137.111.1.255
HostMin: 137.111.1.1
HostMax: 137.111.1.254
Hosts/Net: 254
Department 3:
Address: 137.111.2.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.2.0/24
Broadcast: 137.111.2.255
HostMin: 137.111.2.1
HostMax: 137.111.2.254
Hosts/Net: 254
Department 4:
Address: 137.111.3.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.3.0/24
Broadcast: 137.111.3.255
HostMin: 137.111.3.1
HostMax: 137.111.3.254
Hosts/Net: 254

Department 5:
Address: 137.111.4.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.4.0/24
Broadcast: 137.111.4.255
HostMin: 137.111.4.1
HostMax: 137.111.4.254
Hosts/Net: 254
Department 6:
Address: 137.111.5.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.5.0/24
Broadcast: 137.111.5.255
HostMin: 137.111.5.1
HostMax: 137.111.5.254
Hosts/Net: 254
Department 7:
Address: 137.111.6.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.6.0/24
Broadcast: 137.111.6.255
HostMin: 137.111.6.1
HostMax: 137.111.6.254
Hosts/Net: 254
Department 8:
Address: 137.111.7.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.7.0/24
Broadcast: 137.111.7.255
HostMin: 137.111.7.1
HostMax: 137.111.7.254
Hosts/Net: 254
Department 9:
Address: 137.111.8.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.8.0/24
Broadcast: 137.111.8.255
HostMin: 137.111.8.1
HostMax: 137.111.8.254
Hosts/Net: 254
Department 10:
Address: 137.111.9.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.9.0/24
Broadcast: 137.111.9.255
HostMin: 137.111.9.1

HostMax: 137.111.9.254
Hosts/Net: 254
Department 11:
Address: 137.111.10.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.10.0/24
Broadcast: 137.111.10.255
HostMin: 137.111.10.1
HostMax: 137.111.10.254
Hosts/Net: 254
2. Macquarie Business School
Department 1:
Address: 137.111.16.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.16.0/24
Broadcast: 137.111.16.255
HostMin: 137.111.16.1
HostMax: 137.111.16.254
Hosts/Net: 254
Department 2:
Address: 137.111.17.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.17.0/24
Broadcast: 137.111.17.255
HostMin: 137.111.17.1
HostMax: 137.111.17.254
Hosts/Net: 254
Department 3:
Address: 137.111.18.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.18.0/24
Broadcast: 137.111.18.255
HostMin: 137.111.18.1
HostMax: 137.111.18.254
Hosts/Net: 254
Department 4:
Address: 137.111.19.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.19.0/24
Broadcast: 137.111.19.255
HostMin: 137.111.19.1
HostMax: 137.111.19.254
Hosts/Net: 254
Department 5:
Address: 137.111.20.1
Netmask: 255.255.255.0 = 24

Network Address: 137.111.20.0/24
Broadcast: 137.111.20.255
HostMin: 137.111.20.1
HostMax: 137.111.20.254
Hosts/Net: 254
Department 6:
Address: 137.111.21.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.21.0/24
Broadcast: 137.111.21.255
HostMin: 137.111.21.1
HostMax: 137.111.21.254
Hosts/Net: 254
3. Faculty of Human Sciences
Department 1:
Address: 137.111.32.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.32.0/24
Broadcast: 137.111.32.255
HostMin: 137.111.32.1
HostMax: 137.111.32.254
Hosts/Net: 254
Department 2:
Address: 137.111.33.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.33.0/24
Broadcast: 137.111.33.255
HostMin: 137.111.33.1
HostMax: 137.111.33.254
Hosts/Net: 254
Department 3:
Address: 137.111.34.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.34.0/24
Broadcast: 137.111.34.255
HostMin: 137.111.34.1
HostMax: 137.111.34.254
Hosts/Net: 254
Department 4:
Address: 137.111.35.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.35.0/24
Broadcast: 137.111.35.255
HostMin: 137.111.35.1
HostMax: 137.111.35.254
Hosts/Net: 254

4. Faculty of Medicines and Health Sciences
Department 1:
Address: 137.111.48.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.48.0/24
Broadcast: 137.111.48.255
HostMin: 137.111.48.1
HostMax: 137.111.48.254
Hosts/Net: 254
Department 2:
Address: 137.111.49.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.49.0/24
Broadcast: 137.111.49.255
HostMin: 137.111.49.1
HostMax: 137.111.49.254
Hosts/Net: 254
Department 3:
Address: 137.111.50.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.50.0/24
Broadcast: 137.111.50.255
HostMin: 137.111.50.1
HostMax: 137.111.50.254
Hosts/Net: 254
Department 4:
Address: 137.111.51.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.51.0/24
Broadcast: 137.111.51.255
HostMin: 137.111.51.1
HostMax: 137.111.51.254
Hosts/Net: 254
Department 5:
Address: 137.111.52.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.52.0/24
Broadcast: 137.111.52.255
HostMin: 137.111.52.1
HostMax: 137.111.52.254
Hosts/Net: 254
5. Faculty of Science and Engineering:
Department 1:
Address: 137.111.64.1
Netmask: 255.255.255.0 = 24

Network Address: 137.111.64.0/24
Broadcast: 137.111.64.255
HostMin: 137.111.64.1
HostMax: 137.111.64.254
Hosts/Net: 254
Department 2:
Address: 137.111.65.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.65.0/24
Broadcast: 137.111.65.255
HostMin: 137.111.65.1
HostMax: 137.111.65.254
Hosts/Net: 254
Department 3:
Address: 137.111.66.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.66.0/24
Broadcast: 137.111.66.255
HostMin: 137.111.66.1
HostMax: 137.111.66.254
Hosts/Net: 254
Department 4:
Address: 137.111.67.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.67.0/24
Broadcast: 137.111.67.255
HostMin: 137.111.67.1
HostMax: 137.111.67.254
Hosts/Net: 254
Department 5:
Address: 137.111.68.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.68.0/24
Broadcast: 137.111.68.255
HostMin: 137.111.68.1
HostMax: 137.111.68.254
Hosts/Net: 254
Department 6:
Address: 137.111.69.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.69.0/24
Broadcast: 137.111.69.255
HostMin: 137.111.69.1
HostMax: 137.111.69.254
Hosts/Net: 254
Department 7:

Address: 137.111.70.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.70.0/24
Broadcast: 137.111.70.255
HostMin: 137.111.70.1
HostMax: 137.111.70.254
Hosts/Net: 254
Department 8:
Address: 137.111.71.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.71.0/24
Broadcast: 137.111.71.255
HostMin: 137.111.71.1
HostMax: 137.111.71.254
Hosts/Net: 254
Department 9:
Address: 137.111.72.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.72.0/24
Broadcast: 137.111.72.255
HostMin: 137.111.72.1
HostMax: 137.111.72.254
Hosts/Net: 254
Department 10:
Address: 137.111.73.1
Netmask: 255.255.255.0 = 24
Network Address: 137.111.73.0/24
Broadcast: 137.111.73.255
HostMin: 137.111.73.1
HostMax: 137.111.73.254
Hosts/Net: 254
Part 2: Applications, Protocols and Layering
Question 3: Application Protocols
Ans: Two Application that are choose from the list are: The Domain Name System and
Electronic Mail.
a.
 The Domain Name System itself uses its protocol which is known as DNS Protocol which
resides at application Layer.
 The Electronic Mail Uses SMTP, POP, IMAP and MIME protocol of Application Layer but
main protocol is SMTP.
b.
DNS protocol help the given application by Resolving the given IP address by its name. It helps
to route packets from one source to other destination (Bradshaw & DeNardis, 2016).

 SMTP is the famous protocol used for Electronic Mail. This protocol helps to transfer
messages in the form of Email from “Mail server to the registered Recipients”. SMTP works
on TCP connection.
c.
 DNS is connectionless protocol which means it doesn’t need handshaking to established a
connection that why it uses UDP protocol of transport layer.
 SMTP is connection-oriented protocol which required 3 way handshaking to establish the
connection that’s why it uses TCP protocol of transport layer.
d.
TCP is responsible that each and every packet should be reach to its destination without any
drop. SMTP is Mail Exchange protocol and in every email each packet is equally important to
reach to its destination else it may be possible that the important information doesn’t reach to the
destination. That’s why SMTP uses TCP packet (Liyanage & Fernando, 2017).
 DNS servers generally don’t keep connection alive. One more reason to use UDP for DNS is
that it only transmit small packets which get fitted in the segment of UDP datagram. Once
host entry gets save in database of DNS it doesn’t need any connection to connected every
time with the host.
e.
 Both DNS and SMTP uses client-server architecture because SMTP has a mail server which
is requested by client for the service and for client DNS server uses Domain Server.
f.
Since both the application uses same client-server architecture so let’s explain it commonly.
 In SMTP, one client request from the SMTP server to send mail to another client. Whereas
receiving client request SMTP server for receiving the message.
In DNS when a client request for any page on website or any host, it hit the DNS server for
appropriate name with associate with the IP and forward it to the other client (Kong & Won,
2017).
References
Bradshaw, S. and DeNardis, L., 2016, March. Privacy Concerns in the Domain Name System.
TPRC.
Liyanage, G. and Fernando, S., 2017, December. A comprehensive secure email transfer model.
In 2017 IEEE International Conference on Industrial and Information Systems (ICIIS) (pp. 1-5).
IEEE.
Kong, K.W. and Won, Y., 2017. Implementation of Encrypted Mail Program using SMTP and
POP3. Journal of Digital Contents Society, 18(7), pp.1403-1409.