Exam paper for my PG Diploma

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l'tSemester of the Examination
Network Models & tP
Module Code PGDCN 1102
This question paper contains six (6) questions. Answer any four (4) q
All questions carry equal mark.
(or1
(1) Explain the role of a reference model and why it resembles a layered approach
(5 Marks)
(2) Explain the structure of the oSl model in terms of function and pDU,s in each layer
(74 Marks)
(3) Draw the structure of a data frame and explain its function (6 Morks)
(oz1
(1) ldentify one main feature and one device in each of the 3 layers in the Cisco
hierarchical model and explain why the distribution layer is considered the SMART
layer compared to the access and core layers (S Marl<s)
(2) Discuss three main benefits of using a hierarchical network model approach in
network design (G marks)
(3) ln a hierarchical model what is the difference between the logical layout and the
physical layout? (5 Marks)
(4) Discuss the traffic flows that have to be considered in hierarchical network design
and explain the importance of such an analysis. fi Marks)
(5) what is meant by "tJser communities' andlyses" in network design? (2 Morks)
(ol1
(1) Find the subnet address, broadcast address, CtDR (/) notation,
the following (S Marks)
a. lP address - 193.i.65.33.41 Mask - 255.255.255.224
b. lP address - 10.236.73.21 Mask * 255.255.0.0
and address range of
Page 1 of 3

2. (a4)
(2) Assume that you have been given a class C block to create subnets. Depending on
the number of bits used for the subnet, fill in the following table (74 Marks)
No. of bit used
for the subnet
Subnet
mask
CIDR No. of subnets No. of hosts per subnet
(3) Which of the following can be a beginning address of a subnet block that contains L6
possible lP addresses (3 Marks)
a.205.L6.37.32
b. 190.L6.42.44
c. 17.17.33.80
d. 1-23.45.24.t60
Briefly Explain the difference between concepts of subnet and supernet with the
help of suitable diagrams (6 Mqrks)
A supernet has a first address of 205.L6.32.0 and a supernet mask of 255.255.248.0.
How many blocks are in this supernet considering a default mask of 124 and what is
the range of possible addresses? (4 Marks)
An lSp is granted a block of addresses starting with 203.115.0.0/16. The ISP needs to
distribute these addresses to three groups of customers as follows (Note: No need to
provide provisions for future growth) :
a. The first group has 64 customers; each needs 252 addresses'
b. The second group has 128 customers; each needs 124 addresses.
c. The third group has 128 customers; each needs 60 addresses.
(1)
(2)
(3)
Design the subnet blocks as Per the
last subnet for each group, subnet
each group (75 Morks)
given requirement. Clearly indicate the first and
mask, and the number of addresses allocate for

3. (as)
A transportation company is given the lP block 1.50.0.12.0/24 and has the following
requirements:
a. Marketing department with 50 computers
b. Finance departments with 14 computers
c. Adrninistration department has 30 computers
d. 2 logistics departments are extended from two point to point links
e. Each logistic department has B computers
(1) Design the subnets from the given block using variable length subnet masking
techniques (VLSM) for the departments and the point-to-point links indicating clearly
the subnet address, mask, and the address range for each subnet (27 Marks)
(2) Draw a conceptual design indicating the subnets connected via three routers and
switch distribution layer of the design in carried out above(4 Marks)
(oe1
Write comprehensive discussions on any3 of the following topics. lnclude clear
definition of concepts, applications, advantages and disadvantages for each
' discussion (25 Morks)
(1) ls a 32 bit address space sufficient for lnternet Protocol (tp) in future?
(2) Network Address Translation (NAT)
(3) Route summarization
(4) DMZ in an enterprise network
(5) lPva Header
(6) Distance vector Vs Link state routing
f*."-*
Page 3 of 3

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#sfitrftd.rNational School of Business Management
Postgraduate Diploma in Computer Network_Batch 03
1.t Semester Examination
Computer Network Design
PGDCN 1101
Answer Q4 and other Two (02) euestions.
Time:03Hrs
03 January 2015
Q1
(a) List down three main types of Computer Network design
(b) what are the 6 main phases of network design ,, pur ih" top-down network design approach?(c) "Focus on Layer 7 dnd obovefirst',
(i) Explain the above statement on computer network designing approaches in your own words.
(ii) Compare the above statement with the methodology presented in Top Down Design
approach.
(d) Many network design tools and methodologies that have been used resemble the ,,connect-the-
dots" game. Explain the drawback of this methodology.
{e) write down short notes on one (01) of following topics with regard to Network Design
i) 80 /20 rule ' ii) Management View iii) Technical View
Q2 Networks are usually classified using three properties namely Topology, protocol & Architecture.(a) List down Four (04) main benefits of computer Networking .
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(3)(b) Name 4 variations of computer network toporogies with a schematic diagrams. (5)
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Describe with yourown words and provide three examptes for (s)
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,0, characreristics for each of peer-to peer and ctient server network (s)
(e) write a short note on one (01) of the followings. Your note should address basic features, (7)advantages / disadvantages and Real life applications.
i) client server Technology ii) Thin-client Architecture iii) Thick Client Architecture
q3
(a) what are the three rayers of cisco's hierarchical network design?
(b) IPA(drE6s irz-rso o
(3)
(s)
(s)
(s)
(7)
(c)
(d)
Design a network addressing scheme that will supply the minimum number of subnets, and
allow enough extra subnets and hosts for 100%groMh in both areas. Answer the questions
producing your workings.
i) Minimum number of subnets required
ii) Total Number of subnets required with 100% groMh
iii) Number of Host Addresses in largest subnet
iv) Total number of Host Addresses required in largest subnet with 100% growth
v) List down lP address ranges for the newly designed subnets.
Name four (4) tools that can be used to characterize a Network?
why do static and default routing still play a role in many modern network designs?
(3)
(12)
(s)
(s)
lPA.ldrE6s 172.16.0.0
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(Q4) Carefully read the following paragraph and answer the questions with your own assumptions.
Sahana Hospital is located in Colombo, with approximately 500 staff members supporting up to 1000 patients.
The hospital is interested in updating its network (which currently uses equipment from various vendors). The
Hospital has 15 buildings in total on the campus, plus 5 small remote clinics. There are two main hospital
buildings and an auxiliary building. The two main. buildings have seven floors each, with four wiring closets per
floor. The auxiliary building-the Children's Place-is connected to the two main buildings; the switches from
these three buildings are connected with fiber connections in a ring. The Children's Place has three floors, with
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three wiring closets per floor. The other
12 campus buildings are smaller office
and suppofc facilities, with j.0 to 40
people per building, located on one or
two floors.
The hospital is aggressively expanding its
clinic around the County. Hospital's plan
to enlarge the main campus network is
also under way. The hospital is doing
fairly well financially. lt wants to
selectively deploy cutting-edge
technology for better patient care and
high productivity, Management is tired
of network downtime and slowness
affecting patient care. Network
manageability is important because
Sahana has a tradition of working with
limited support staffs with high
productivity.
The current network uses inexpensive
Srnallar Brrildingg
switches from several vendors, purchased over time. They comply with various standards, depending on when
they were purchased. The switches are not SNMP-manageable,,although a small amount of information is
available frorn each switch via the web or command-line interfacb. Within each of the three main buildings is a
main switch. One floor switch from each floor connects to the main switch. The small outlying buildings have one
or two 24-port switches. One of these connects back to one of the main building switches via fiber. lf there is a
second switch, it connects via the first switch.
Currently, the staff VLAN spans the entire campus. No Layer 3 switching is present. The address space is
172.16.0.0 /16. Addresses are coded sequentially into PCs as they are deployed. Staff members havetried to
deploy DHCP but is not completed yet.
The applications that the organization is currently running include standard office applications, plus some
specialized medical tools running over lP. Radiology, Oncology, and other departments do medical imaging. As
these departments acquire new tools, they are adding real-time motion to the highly detailed medical images,
requiring large amounts of bandwidth. All the new servers are capable of using Gigabit or Gigabit EtherChannel
connectivity
Many servers are currently located in various closets. Many lack uninterrupted power supplies or proper
environrnental controls. A staff member has to roll a tape backup cart to each server closet to back up each
server. There are about 40 centrally located servers in one raised floor "server room," and 30 other servers
distributed around the campus near their users. The server room takes up part of the first floor of Main Building
1, along with the cafeteria and other non-networked areas.
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The WAN uses 56-kbps links to three of the remote clinics and dialup connectivity to the other two. The one
router uses static routing that was configured by a previous network designer. The staff members have
frequently complained about slow response times. There appears to be severe congestion of the LAN, especially
at peak hours"
a. List down at least five business goals of Sahana Hospital trying to achieve upgrading their network.
(5)
ldentify at least 5 major user groups of the Hospital Network and create a table with columns User group,
Major Network application they use, Location.
, (s)
The proposed network should achieve technical goals in the categories of Scalability, Availability, Network
performance, Security, Manageability, Usability, Adaptability and Affordability.
(1s)
i) Out of these technical goals list down three most important technical goals as per the case study.
ii) Suggests technical solutions to Sahana Hospital to address each ofthe above selected technical goals.
your answer should include current status of the goal, Technical lmplementations you propose and effect
on the business goals from the proposed technical implementations'
iii) "The hospital is doing fairly well financially'' discuss as a network designer what technical goal you can
trade off with and how it help to achieve better results for other important technical goals,
* *,1.**END:1. ****
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7. rr J^'
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National Schoo! of Business Management
Post Graduate Diploma in Computer Networks-Batch 3
l't Semester Exa mination
Routing and Switching
(PGDCN 1103)
Time:3 hrs 21 December 2OL4
I n st r u cti o ns to co n d i d otes :
o Question Q7 is compulsory.
o Answer 3 questions from Q2 to Q5.
t Electronic Colculotors are ollowed.
Following Q1 is compulsorv.
Ql.Clearly indicate the configurations of the following network together with
t.
il.
ilt.
The redistributions of routes between each routing protocols.
OSPF Virtual Link from Area Zto Area 0
Configurations of all the routers to be included, and finally you should be able to ping
from Router0 to Router6. Assume you are using Cisco equipment.
(40 marks)
_@lF----
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Answer three (3) Questions from the followinq questions e2 to e5.
Q2.
l. Briefly explain Routing rnformation Base (RrB) and Forward
interaction with the aid of a diagram.
ll. Briefly explain the following tbchniques to avoid routing loops
lnformation Base (FlB)
(10 marks)
o Split Horizon
o Poison reverse
o Holddown
o Triggered Updates
o Aging of routes from the routing table
Q3.With regards to the Spanning Tree protocol (STp)
l. Briefly explain the followings:
(10 marks)
(10 marks)
a) port Fast
b) Rootguard
c) Loop guard
d) BPDU guard
ll. Describe the rules of the spanning Tree Protocol in a single LAN segment with a single
VLAN -,. (10 marks)
Q4. With regards to the VLAN Trunk protocol(Wp)
l. what are the VLAN Trunk Protocol (VTP) modes of operations? Briefly explain them.
(10 marks)
ll. What is wP Pruning? Why it is necessary for a LAN segment with several VLANs
(10 marks)
Q5.what are the criteria used by routing protocols to select a best route for a given destination?
Briefly explain 3 of them. (20 marks)
,** ** *EN D*****

9. -3--
fuseai'}'
National School of Business Managernent
Post Graduate Diplorna in Computer Networks_Batch 03
2nd Semester Examination
Network planning lmplementing and Administration
(PGDCN 1103)
r)
Answer All Questions.
Time:3 hrs
22 November 2015
Question 1
a' what are the best practices on designing a corporate computer network & critically evaluateon network security by taking the layered rnodel
b'
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explain rive benerits or imprementing structflI':||lr;
(2 Marks)a' when implement a wireless network what are the best practices that you can appry. stateand explain advantages of a centralized management sybtem to manage and controrwireless access points.
(L0 Marks)
Question 2
Question 3
a' when implementing computer networks, you often have to work with solution vendors(note: sorution vendors, not equipment vendors). Name three pitfails that you may facewhen working with sorution vendors. Exprain how they .rn-n" avoided. (10 Marks)b' ln significantly large projects, you may have to procure the services of a consurtant to
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anarvze the sorution. state and exprain three advantases of hiring a
(Total- 20 Marks)
(10 Marks)
(Total- 20 Marks)
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a' A service Level Agreement (sLA)-is a contractual agreement between a customer and avendor for maintenance of a specific entity in .n org.iirution. state and explain five benefitsan organization achieves by having an SLA with a u"ndor.
b' A modern tendency is for organizations to obtain managed services, *n.rtor';jXtJ",organization undertakes the complete ownership and maintenance of equipment instaged bythem' List and describe five benefits of the managed services model. (10 Marks)
euestion 4 (Total_ 20 Marks)
a'
:fi:i:rT"
term Business continuitv Planning. How does it differ from Disaster Recovery
b' How does cloud computing help an organization to achieve business .on,,n.jl,#'llo',r,.three drawbacks of using a cloud computing service for an organization. (5 Marks)c' Analyze Data center best practices for an oiganization ..n .ppty and follow. (g Marks)
euestion S (Total_ 20 Marks)
a'
fl::t:i:"
benefits of cloud computing giving exampres in each croud computing service
b' A large organization mav use a Network operations centre (Noc) to monitor :lXH[:"routine activities in a network' Under what circumstances would an organization decide toimplement a Noc? Evaluate three benefits of having a Noc in an organizr;;.' (10 Marks)
(Total_ 20 Marks)
t*x*jNEnd
of the paper*****
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10. Answer A11 Questions
National School of Business Management
Postgraduate Diploma in Computer Networks-Batch
Semester 1
Voice and TelePhonY Technologies
(PGDCN12o5)
Time: 03Hrs
tB January 2015
1. (A) ExPlain in
PBX.
brief 4 (fo1r) criteria which must be evaluated before niigrating from iegacy PBX to an IP
Q Marks)
(6 Marks)
(5 Marks)
(B) A CISCO irnplementation of a VoIP network had certain parameters set in IOS as shown beiow.
(a) 6G.T2gvoicepacket ot20bytes isgeneratedeveryl0rns. Buteachfra,meconsistsof two(2) such
packets of a total of 80 bytes (after adding payload)
There is an initiai "lookahead" delay of Sm's for each packet'
There is a possible queuing clelay of 4m; in the 128kbps trunk'
Network cielay of 1ms it a private trtink line is used, and 8rns if public frame relay network is used
for WAN connectivitY.
(e) 50nr,s at the de-jitter buffer'
Answer parts (i)-(iv) taking this data into account'
(i) Caiculate the serialization delay. Q Marks)
(ii) Calculate tlte "fixed" delay encouutered by a VoIP call' (3'5 Ma'rks)
(iii)Calcuiatethe..variable,,delayencounteredbyaVolPcall.(3.5Marks)
(iv) It is notecl that the ,,header size" of each frame is twice that of the "payload", which has resulted
in higher serialization delay. What is the remedy that you can take for this issue? Are there any
negative side-effects in the mechanism that you propose? (5 Marks)
(c) A volp cail which terminated at a PSTN client (B-party is PSTN side) was noticed to have ettrernelu
,oor quatity. The trace file extractecl from the call, wherr analyzed revealed that it was ronted through
u CSfrA rretwork. Expiain in brief possible reason(s) for the poor quaiity' (5 IUIarks)
2 (A) (i) trxplain in brief 4 (four) disadvantages with regard to deploying an IP based phone system over a
. traditional pBX system for a business organization with-an existing PBX solution. (5 Marks)
(ii) Explain in brief the use of:
(a) trXO (foreign exchange card)
(b) PoE modules for layer-3 srvitches (wiih a suitable diagram)
(iii) What are the ma.ior diffetences between H'323 and SIP?
(B) A G729 cod.ec produces encoderl bits at the rate of 8l{bps. The payload is 20 bytes and when c'RTP
is used the compressed lp/uDp/Rrp header sizeis2 bytes. Multilink Point-to-Point Protocol (MP)
aclcls a 6 byte heacler in front of IP header. Calculate the ba'ndwidth per cail' (9 Marks)
3. (a) Draw a ciiagram showing the equipment used for Digital Subscriber Loop (D,9I) connectivitv for a VoIP
gateway. Label the equipments clearly and explain their functionality in brief. (5 Marks)
(b) Show with the tise of diagram, if necessary how D,Str obtains higher data rate transmission using higher
orcler rnoclulation schemes as opposed to legacy 56k dial up rnodems. (5 Marks)
(c) Explain the effect of,
i. Distance
ii. CopPer wire thickness
(b)
(.)
(d)
on ADSL performance (data rate)'
(cl) Explain in brief the clifference between I{DSL arfi ADSL (use diagrams if necessary).
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(5 Marks)
(5 Marks)

11. (e) For a particular ADSL modem at custoraer preniises, the following status information was letrieved.
ADSL Firmware Version: 4.01 .00.00 - 1.01.00.00 - 1.01.00.00.A.rurex A - 01.06.06 - O.49
Modulation Multi-mode
Annex Mode ANNEX-A
Max Tx Power -38 dBm/Hz
Item Doi^rnstream UPstream Unit
SNR Margln 30
Line Attenuation 20
6dB
27 dB
Data Rate 1536 256 kbPs
Calculate the minirnum received signal.level (Rrrntn) for 1536l,bps connectivity {5 Marks)
4. Best-in-class design states that "no more than 75% of your bandwidth should be used for voice traffic, so as
to not to starve data traffrc". A compressed voice caLl takes 3l.2kfus of bandwidth.
(a) For an El line of bandwidth 2.048Mbps what is the maximum number of simultaneous calls that ca1
be carried, if there is to be no blocking? (l Marks)
(b) If a grade of service (Go.9) of 1% is required, how muclt traffic (in Erlangs) cau be carried over with
this link?
Note: (Jse the graph shown i,n the Append.ir. Marle the releuant trffic in the chart. (6 Marks)
(c) How much traffic carl an EI-PRI link can carry with l% GoS? (6 tularhs)
(d) If you are given the option of selecting between a leg-ac1 PBX with EI'PRI connectivity and the above
Ip pBX with El trunk connectivity, for 1% GoS, which one should you choose ? Give reasons.
Note that EI-PRI is more expensiue than 0,n El di,gital trunk. ( I Marks)
(e) Explain i1 brief a1 advantage and disadvantage in taking the "average traffic interrsity" for traffic
calcllations rather than "busy hour traffic intensity". ( 5 Marks)
end oJ paper.
Appendix
l;1s 2n 60 q0
Numberotchennols 2 $ . 5 I 7Bs10t, 16& 30 1650 m!
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-,,,i l' . ! ! ,i.i.i l-i,i Iti i,[i,0.1 1.0 10.0 100.0
Ttaffic inlensity IErlI
Erlang-B Formula, Tbaffic curves with respect to nurnber of channels and blocking probability
end of append,ir,
2
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12. F
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},SEE{'
Time:03Hrs
Date: 2nd Aug 2015
National School of Business Management
Post Graduate Diploma in Computer Networks- Batch 03
znd semester Examination
Service Provider Networks
PGDCN 1207
kr)
AS
Answer onlY Four (04) Questions
Electronic Catculators are allowed
br)
bs)
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itlr
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Q2.
Q3.
b.
a. Enterprise networks are generally modeled in three layers. List and explain functionality
of each layer. (10 marks)
ln the focus of service provider models, discuss briefly the meaning of provider edge.
(5 marks)
Explain scalability issues in the Modern lnternet. Discuss the key issues and solutions
proposed to avert them with future modifications targeting these issues.
(10 morks)
What is meant by SLA? Explain how availabiliti is bound to the SLA. (5 marks)
List down at least three parameters, which can be used to measure QoS and briefly
explain each of them. fiO marks)
c. Assume that you are the Systems manager of a mid scale lT company in Sri Lanka and
want to obtain a leased line for your co-operate needs. Discuss the items that you would
consider including in to the SLA, with reasoning in order to achieve your organization
goals. (10 marks)
Compare the ITU Telecommunications Management Network (TMN) and IETF POLICY
a.
b.
framework.
what is meant by Routing Policy specification Language (RPSL)?
(5 marks)
(5 marks)b.
c. Explain Advertising/Export Policies and Acceptance/lmport Policies. Explain how the
preference among routing information sources is achieved. (70 morks)
d. Highlight the importance of security policies while discussing the purpose and objectives
of them. (5 marks)
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Page X of 2

13. Q4.
Qs.
Explain the concept of grooming. Using an example and/or a diagram explain why
grooming can cause issues when done automatically or carelessly. (lS morks)
What ii meant by a Media Gateway and the use of it? Describe the gateway architecture
explaining the functionalities of each plane. (70 narks)
a. Briefly describe the similarities and dissimilarities of IBGP and eBGp. (S morks)
b. Explain the terms Multilinking and Multihoming. Give example scenarios where you can
use either Multilinking or Multihoming or a combination of both. (70 morks)
c. Discuss briefly how load sharing can be achieved using specific lp addressing in BGp.
Give suitable examples and diagrams where necessary. (70 marks)
1,,
Page 2 of 2

14. 'it *
guss&?i
National School of Business Managernent
PGD in Computer Networks - Batch 3
2nd Semester Examinatlon
Network Operations
PGDCNl2O8
ry
Time:03Hrs
29 November 2015
I nstru ctio n s for co nd id ate s;
7. Answer ony Four {4) questions only.
2' use diagroms and include exomples when exploining your answers whenever possible.
1,.
a_
b.
what is a network operating system, how does it differs from a desktop operating
system? Explain using examples and indicating 5 features of a Network operatingiystem.
(5 marks)
A process is a program in execution in a computer,s memory. Analyze the steps of theprocess execution Life cycle, indicating the process states in a diagram. (10 marks)
Multitasking enhances the speed of process execution. compare and contrast the two
types of multitasking using a diagram. (10 marks)
{Total- 25 marks}
what is Network Binding? Explain using components used to do binding. you may use a
diagram to explain binding. (10 marks)
Port is a common concept in computer Networking. Recognize port characteristics and
the reasons for using ports. (5 marks)
what is a socket in computer Networking? A socket goes through several states in its life
span. Evaluate socket life cycle using its sates. Draw-qdiagram siowing the
interconnections of various states of the socket life cycle. ( 10 marks)
(Total- 25 marks)
2.
c.
a' ldentify the main components of a cPU. show the interconnection between the
components, RAM and ROM using a diagram. (7 marks)
Modern computer Processors architecture is based on lnstruction set Architecture (lsA).
what is the lnstruction set of a processor? Examine its functionality giving ., Llr, i ilr,",it perform.
(10 marks)
what are crsc and Rrsc computer architectures? compare and contrast the twoarchitectures indicating the key differences and the role of the compiler and how itaffects the programmer. Give exampres for Rrsc and crsc processors. (g marks)
(Total- 25 marks)
b.
3.
b.

15. 4.SupercomputersandMainframecomputerareexamplesofcentralizedsystemsbutnotusedfor
general purpose computing' They are used for special purposes only'
a.Explain5characteristicsofSuperComputersand5characteristicsofMainframe
Computers.Compareandcontrastthekeydifferencesbetweenthetwoarchitectures.(10 marks)
b.WhatisThinClientComputing?RecognizeThinClient3.tierArchitectureusingadiagram
indicatingthe3-tierscrearry.
i K€uu''tttac rlrrrr v're"-- -'-
(5marks)
c.RedundantArrayoflnexpensive/lndependent.Disks,RAlDtechnologyisawayofachieving
fault tolerance at hardwrr" r"r"r. iualuate Raid Levels 0' 1- & 5 explaining the features'
minimum disk requirements unfin *t,rt types of systems we can
""t?:[i- [t#lt*]'
5.PlanningascalablenetworkisnotaneasytaskaSmostofthenetworksgrowbiggerwiththe
time as the requirements change'
a. Describe 4 reasons why we need to create larger networks. Mentions 4; ways to stretch or
expand network capabilities'
:sv rv v' ---- ' " ( B marks )
b.Recognize3deviceswhichwecanusetoexpandorconnectdifferentnetworks.You
shouldmentionthebasictun.tion,ritvofeachdeviceverybriefly.(gmarks)
c.WANsareoftenconstructedbylinkingLANs.Connectionsareestablishedusing
communicationlinestromrspso'.t"t"-.o*providers.Evaluate3typesofcommunication
linesyoucanusetoconnecttwoLANs.Theanswershouldincludefeatures,advantages(8 marks)
Briefly Explain 5 benefits of using virtualization in modern computing (5 marks)6.
a.
b.
C.
Recognize the two types of Hypervisors available' You mav use a diagra*'" o[TTn5"
answer.
whatisoversubscriptioninVirtualization?EvaluateYouranswerusingasuitable
component (such as *t'"'VlCpU)which can be oversubscribed' ( 5 marks)
CompareandcontrastFullVirtualization(HardwareAssistedVirtualization)vsPara-
Virtualization indicating the kev requirements needed in each environmll'-
!i'#lt[s,'
d.
*r.***End of the paper*****
PageZ ol 2

16. .$
SAaqh * .,;i
rubSdg"racJuS#.jr
National School of Business Management
Postgraduate Diploma in Computer Networks _ Batch 03
2nd Semester Examination
Network Security
PGDCN 1309
Answer any five (05) questions.
Time:03Hrs
26 July 2015
Question 1
(a) Describe the three elements depicted by the clA triangle pertaining to network security, with
examples. (g Marks)
(b) Describe the term AAA, in relation to controlling access to computing resources of an
organization. (6 Marks)
(c) Explain how two-factor authentication enables an organization to enforce better security.
(5 Marks)
(Total20 Marks)
Question 2
(a) Explain the following principres in imprementing rr security in an organization
(i) Least privilege principle
(ii) Defense in-depth principle
(12 Marks)
(b) Explain two practical difficulties that may arise,
medium business.
Question 3
(a) Describe the term buffer overflow and how attackers utilize buffer overflow to attack systems
(10 Marks)
(b) Explain two key vulnerabilities present in the sMTp protocor and describe measures that can
be taken by mail server administrators to prevent the exploitation of these vulnerabilities
Question 4
(10 Marks)
(Total20 Marks)
Explain the security risks in the following modern tendencies in organizations and explain how these
risks can be overcome.
(a) Cloud computing
(b) Big data
(c) BYOD (Bring your own device)
(d) lnternet of things
(5 Marks each)
(Total20 Marks)
t"{",t 1'i{*i'{,! {' Si:ll i${}L
t )' {.'
i1: r :- . l| ri l, a;' ltJ'tl
in implementing the above principles in a small or
(8 Marks)
(Total20 Marks)
::
,r
)fZ
Page 1 of 2

17. euestion 5 . . !1, ^^ ^v-6nla (5 Marks)
(a) What is Social Engineering? Explain with an example'
(b) Explain two key ,i"p, tt.,,t can be taken to prevent your company,s employees being
subjected to social engineering attacks' ,.
(5 Marks)
(c) Describe h"*;;; follJwing TCP/IP attacks are carried out
(i) Xmas Tree Attack
(ii) TeardroP Attack
(5 Marks each)
(Total20 Marks)
"'",:1":;,ain the process of carrying out penetration a penerrarion test in an organittt'o1ro
Marks)
(b)Whataretheprerequisitesandtoolsrequiredtocarryoutapenetrationtest(5Marks)
(c) Once a penetration test is completed' what should be done by the
(i) penetration tester and (5 marks)
(ii) Owner of the organization (Total 20 Marks)
{.***,FEnd of the paper**x**
Page 2 of 2

18. -&
ffisffissiNational School of Business Management
Postgraduate fliploma in computer Netwo.tir - llatch CIz & 03
s)
(s)
'ks)
2nd SemesteiExarnination
Disaster Recovery and High availabi nrques
Answer AII Questions
Time:03Hrs
Date: 24 May 2015
Question 0I
In the IT subsystem, disaster recovery is not the same as high availability
i' compare and contrast the use of High Availability Systems and Disaster Recovery
Solutions in business and IT operations. (5 Marks)
Reliability, Availability and Serviceability (RAS) is a set of related attributes that must be
considered when designing, manufacturing, purchasing or using a computer product or
component.
ii' Distinguish key characteristics between Reliability, Availability, and Serviceability
with reference to High Availability and Disaster Recovery planning in modern day
business otganizations. Support your answer with appropriate examples. (5 Marks)
iii' Explain RTo and RPo in your own words and describe the imponun." of correctly
identifying them for each business function/ process/ system. (05 Marks)
iv' when it comes to High Availability why do we take two approaches on Hardware and
Software (e.g. Operating Systems level) separately? (10 Mark$
Question 02
As the IT manager, you need to evaluate technology options for reliably hosting a business
critical ERP Solution, which is interfaced to external custome., trr.orgr, an e-commerce
platform.
The top management has indicated that the ERP must be available 99.99% and maximum
tolerable downtime as 2 hours and maxirnum tolerable data loss as 30 minutes. As the ITManager, you need to strike a balance between the Total cost of ownership and complexity ofoperation.
Briefly explain your solution of choice, indicating the following.
i. System Landscape
ii. Solution Diagram
iii. Preferred Technologies
,,e2of2
Page I of2
(25 Marks)

19. ,, {rt"5
x: e,i'a-r r '
Question 03 u--
Business Continuity and.Disaste'.1:::l*y mu't t key priority and owned and sponsored by
;h.,;;;*agement of the organization' . - t1^^+i-,,*r, ,nrr T)isaster R
i Identifv four (04) driver' to1.P:::X.:,?IIHlLfli' 3..T:tiJrfi;:;'T'
1n an
lffix:'flr,T11, fll-:ffiil;id;;;"*:1.s/description
for each (0 5 Marks)
Elaborate o, pro#il "il;; ,o
,grJ.t",t
iontinuity in your organization/
Environment and o';;l;t "
p'#'i^d #;f ; $ive) with reasons for their ranking'
State your risk scorrig me*roaotogy as well' (10 Marks)
r organizalion' Provi
you are the team rJ;f;ffi;;#'R".";;;y et*ning in vo* organization' Provide a
narrativeastohowyouwouidcarryoutthe"BusinesslmpactAnalysis'(10Marks)
Question 04
ITServiceManagementmainlyfocusedondaytodayoperationsandhandlingofincidentsin
the organization'
i. what is the relevant of IT Services Management to High Availability and Disaster
RecoverY aPProach? (05 Marks)
ii. Brietlv ai'""' ttte impottan'"J
"t:"::-?ll:":
*unugement (Configuration Items
Database - CIDB) with other IT service management areas such as incident
managemerrt,problemmanagemerrt,changernanagementandreleasemanagement
and the relevance with Highlivailauility and Disastet Recovery' (08 Marks)
iii. What are the kev consid"'"tt"" i*"
lt'?l]]*ltd
when designing a data center with
High A;;i;iritv *a Disaster Recovery solutions for a business organization
operatingaclossmultiple*"*,*n'",u",9,.theworld?Youranswermustinclude
locationredundancy,suppottinfrastructuresuchaselectricityandairconditioning,
and PhYsical securitY' (12 Marks)
-End of Examination PaPer-
a'a
4,.
:::
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