Topic: Networks
Assignment Details
Due Date    End of Week 10
Description    Assignment 2 €“ Document €“ Short/Long Answer Questions
Weighting    20% of total assessment.
Submission    Electronic (see course website for details)
Notes    Please use this document as a template for your assignment.
Answer each question fully.  Show working where possible.  Failing to show working will result in a loss of marks in some

questions.
Do not copy answers directly from the textbook or other resources.  You are required to answer the questions using your own

words.  Failing to do so may result in a mark of zero and possible action in relation to plagiarism.
Ensure that you number and label each question as it appears on this document.
Use Harvard style referencing where appropriate.

Please fill in the following details:
Student Name
Student Number

Q1 /6    Q2 /5    Q3 /7    Q4 /6    Q5 /6    Q6 /10    /40
0
Question 1    (6 Marks)

A workstation sends an ICMP timestamp request to a server.  It receives the corresponding timestamp reply at exactly 10:20:34

pm (Universal Time).  The original timestamp was 83,808,780.  The receive timestamp was 86,060,920.  The transmit timestamp

was 80,061,010.
Show all working for all parts.  You may find it useful to draw a timeline of the events.
a)    What is the sending trip time?
b)    What is the receiving trip time?
c)    What is the round-trip time?
d)    What is the difference between the sender clock and the receiver clock?
e)    What adjustment needs to be made to the workstation in order to synchronise its clock with the servers clock?  Make

sure you state your answer clearly, in a sentence.

Your Answer:

a)

b)

c)

d)

e)

Marks Awarded:
Comments:

Question 2    (5 Marks)

What is the minimum number of UDP datagrams required to return a TFTP file 28,564 bytes in size from a server over an

Ethernet connection?
Show all calculations you use to obtain your answer.  (You do not need to account for TFTP protocol overheads €“ assume this

is included in the total byte count).

Hint:  determine the maximum UDP data field length first.

Your Answer:

Marks Awarded:
Comments:

Question 3    (7 Marks)

A sending application has sent 120 bytes to a receiving application using TCP.  The congestion window (cwnd) is set at 100

bytes (assume it does not change for the duration).  The receiving application has sent an acknowledgement number of 101 with

a receiver window (rwnd) of 100 bytes.
a)    Draw a diagram showing the sliding window and next byte pointer similar to the example provided below based on the

details given above.
b)    The sending application then receives a further acknowledgment of byte 121 with an rwnd of 100 bytes.  Draw a diagram

representing the new sliding window and next byte pointer.
c)    The sending application then sends a further 100 bytes to the receiving application, which responds soon after with

an acknowledgement of byte 141 with an rwnd of 100 bytes.  Draw a diagram representing the new sliding window and next byte

pointer.
d)    What is the maximum amount of data the sending application can send at this time?

Example of diagram required, showing sliding window and next byte pointer.

101-120    121-140    141-160    161-180    181-200    201-220    221-240    241-260    261-280    281-300

Your Answer:

Marks Awarded:
Comments:

Question 4    (6 Marks)
Describe, with the use of an example, how router table updates occur when RIP is used.  Your description should include

details of the timers used and the events that trigger updates.

Your Answer:

Marks Awarded:
Comments:

Question 5    (6 Marks)

Given the network topology below which uses Link State Routing, create the routing tables for each node.  (Use the Dijkstra

algorithm.)

Your Answer:

Routing table for node A        Routing table for node B
Node    Cost    Next Router        Node    Cost    Next Router
A                A
B                B
C                C
D                D
E                E
F                F

Routing table for node C        Routing table for node D
Node    Cost    Next Router        Node    Cost    Next Router
A                A
B                B
C                C
D                D
E                E
F                F

Routing table for node E        Routing table for node F
Node    Cost    Next Router        Node    Cost    Next Router
A                A
B                B
C                C
D                D
E                E
F                F

Marks Awarded:
Comments:

Question 6    (10 Marks)
The exhaustion of IPv4 address pool has hastened the change-over to IPv6.  However the transition poses challenges to just

about every stakeholder involved in the delivery and consumption of Internet bandwidth.

Your task is to develop a discussion paper outlining the challenges and benefits of the transition to IPv6.  You should

consider multiple perspectives (for example, ISPs, hardware vendors, bandwidth consumers etc.).  You should discuss

transition strategies and requirements and identify major vendors, organisations and sites who are early adopters and change

leaders.

Your paper should be between 1500 and 2000 words (including references).  Reference ALL sources (including direct quotes,

diagrams and tables).  You are required to use external sources (i.e. beyond your textbook) to complete your discussion paper

e.g. Journal Articles, Scholarly Papers, etc.

Marking Scheme:

Discussion of benefits    2 Marks
Discussion of challenges    3 Marks
Discussion of transition arrangements    2 Marks
Discussion of change leaders    2 Marks
Clarity of communication    1 Mark

Note: No marks are awarded for referencing.  However, marks will be deducted for every instance of:
Failure to cite in-text correctly
Failure to include & correctly cite all references in the References section
Failure to identify and cite text in your assignment that is not your own

Each instance will result in a deduction of 1 mark to a maximum of 6 marks.

Note:  Should plagiarism be suspected, normal faculty processes will be followed.  This may result in penalties including,

but not limited to, zero marks for the assignment or formal disciplinary proceedings.