Subnetting and Network Layer

COMP247
ASSIGNMENT 1 2019
DATA COMMUNICATION

QUESTION 1: Subnetting and Network Layer
a) Equivalent Subnet masks denoted-decimal notation for the following slash-notation
address block
I. /21 – 255.255.248.0 = 21
11111111.11111111.11111 000.00000000
II. /13 – 255.248.0.0 = 13
11111111.11111 000.00000000.00000000
III. /29 – 255.255.255.248=29
11111111.11111111.11111111.11111 000
b) Number of Hosts addresses on the network
I. /19 – 192.168.0.1 – 192.168.31.254
(8190 Host) Private Internet
II. /30 – 192.168.0.1 – 192.168.0.2
(2 Host) Private Internet
III. /23 – 192.168.0.1 – 192.168.1.254
(510 Hosts) Private Internet
2) If the following slash notation are legal
I. 255.255.224.0 - /19 11111111.11111111.111 00000.00000000
(192.168.0.1 – 192.168.31.254) 8190 Host
II. 255.128.0.0 - /9 11111111.1 0000000.00000000.00000000
(192.128.0.1– 192.255.255.254) 8388606 Host
III. 255.252.255.0 Corrected illegal net mask 255.252.255.0 to 255.252.0.0
Net mask 255.252.0.0 = 14 11111111.111111 00.00000000.00000000
(192.168.0.1 – 192.171.255.254) 262142 Hosts
IV. 255.255.255.254 -/31 11111111.11111111.11111111.1111111 0
(192.168.0.1 – 192.168.0.1) 0 Hosts

Question 2: Application, Protocol and Layering
Application Chosen: Electronic Mail and Bit – Torrent
a) Application layer protocol does my chosen application use.
Electronic Mail – Simple Mail Transfer Protocol (SMTP)
Bit Torrent – File transfer protocol (FTP) and Point to point (P2P)
b) A brief summary of each protocol that is used in relation to the application protocol.
Electronic Mail
Simple Mail Transfer Protocol
This application layer protocol uses the rule of store and forward in the process of
communication between two nodes whereby it moves email across and within the network. It
is a part of the TCP/IP protocol and with this protocol one is able to send and receive
messages. It is one of the most used and common protocol of communication since it
provides a basic intermediate mode of service between the senders the email server and the
local user accessing the email [1].
The SMTP is simple integrated into the following application components
 Mail User Agent – this is a web based application program the provides the platform
for the message management, its composition and the reception facilities before
submitting to the other parties involved in the process of communication.
 Mail Submission Agent – this is a web based application program the receives the
message from the mail use agent and integrates it with the mail transfer agent to
deliver the email
 Mail Transfer Agent – this acts as a communication channel between the sender and
the email receiver. It’s also referred to as the exchange of contents
 Mail Delivery Agent – it’s the final hop of the email that give back the response for
the delivered email to the receiver mailbox
This type of communication was developed in the 70’s. This is found on the phases of the
OSI Modelling [2]. This is a build of communication protocol used to trans communicate
through devices on the network. It can also be used as a transmission network protocol to
private network.