Assignment AAns.1.It is important to use dedicated project managers to oversee projects from conception to completion. Understanding effective project management techniques helps organizations carry out large-scale projects on time, on budget and with minimal disruption to the rest of the business. Project management techniques are specific to dealing with one-time projects. They can create plans to manage interdependence and address resource conflict. Organizations that use project management to monitor and control processes and schedules can more effectively complete their projects on time and on budget.Basically, CPM (Critical Path Method) and PERT (Programme Evaluation Review Technique) are project management techniques, which have been created out of the need of Western industrial and military establishments to plan, schedule and control complex projects.Far more than the technical benefits, it was found that PERT/CPM provided a focus around which managers could brain-storm and put their ideas together. It proved to be a great communication medium by which thinkers and planners at one level could communicate their ideas, their doubts and fears to another level. Most important, it became a useful tool for evaluating the performance of individuals and teams.There are many variations of CPM/PERT which have been useful in planning costs, scheduling manpower and machine time. CPM/PERT can answer the following important questions:How long will the entire project take to be completed? What are the risks involved?Which are the critical activities or tasks in the project which could delay the entire project if they were not completed on time?Is the project on schedule, behind schedule or ahead of schedule?If the project has to be finished earlier than planned, what is the best way to do this at the least cost?

Ans.2. A queueing theory is the study ofqueues as a technique for managing processes and objects in a computer. A queue can be studied in terms of: the source of each queued item, how frequently items arrive on the queue, how long they can or should wait, whether some items should jump ahead in the queue, how multiple queues might be formed and managed, and the rules by which items are enqueued and dequeued.Inqueueing theory, a discipline within the mathematicaltheory of probability, anM/M/1 queuerepresents the queue length in a system having a single server, where arrivals are determined by aPoisson processand job service times have anexponential distribution. The model name is written inKendall's notation. The model is the most elementary of queueing modelsand an attractive object of study asclosed-form expressionscan be obtained for many metrics of interest in this model. An extension of this model with more than one server is theM/M/c queue.The M/M/n Queue It is a variation of the classical queue assuming that the service is provided by n servers operating independently of each other. This modification is natural since if the mean arrival rate is greater than the service rate the system will not be stable, that is why the number of servers should be increased. However, in this situation we have parallel services and we are interested in the distribution of first service completion.

Ans.3.a). Note On Phases of Networking Planning and Design PPDIOO stands for Prepare, Plan, Design, Implement, Operate, and Optimize. PPDIOO is a Cisco methodology that defines the continuous life-cycle of services required for a network.PPDIOO PhasesThe PPDIOO phases are as follows: Prepare:Involves establishing the organizational requirements, developing a network strategy, and proposing a high-level conceptual architecture identifying technologies that can best support the architecture. The prepare phase can establish a financial justification for network strategy by assessing the business case for the proposed architecture. Plan:Involves identifying initial network requirements based on goals, facilities, user needs, and so on. The plan phase involves characterizing sites and assessing any existing networks and performing a gap analysis to determine whether the existing system infrastructure, sites, and the operational environment can support the proposed system. A project plan is useful for helping manage the tasks, responsibilities, critical milestones, and resources required to implement changes to the network. The project plan should align with the scope, cost, and resource parameters established in the original business requirements. Design:The initial requirements that were derived in the planning phase drive the activities of the network design specialists. The network design specification is a comprehensive detailed design that meets current business and technical requirements, and incorporates specifications to support availability, reliability, security, scalability, and performance. The design specification is the basis for the implementation activities. Implement:The network is built or additional components are incorporated according to the design specifications, with the goal of integrating devices without disrupting the existing network or creating points of vulnerability. Operate:Operation is the final test of the appropriateness of the design. The operational phase involves maintaining network health through day-to-day operations, including maintaining high availability and reducing expenses. The fault detection, correction, and performance monitoring that occur in daily operations provide the initial data for the optimization phase. Optimize:Involves proactive management of the network. The goal of proactive management is to identify and resolve issues before they affect the organization. Reactive fault detection and correction (troubleshooting) is needed when proactive management cannot predict and mitigate failures. In the PPDIOO process, the optimization phase can prompt a network redesign if too many network problems and errors arise, if performance does not meet expectations, or if new applications are identified to support organizational and technical requirements.

Ans.3.b).

Ans.4.Delay : In networking, the amount of time it takes apacketto travel from source to destination. Together, latency and bandwidthdefine the speed and capacity of anetwork. There are mainly 4 types of delay in switches:1. Processing delay: In anetworkbased onpacket switching,processing delayis the time it takesroutersto process thepacket header. Processing delay is a key component innetwork delay.During processing of a packet, routers may check for bit-level errors in the packet that occurred during transmission as well as determining where the packet's next destination is. Processing delays in high-speed routers are typically on the order of microseconds or less. After this nodal processing, the router directs the packet to the queue where further delay can happen (queuing delay).In the past, the processing delay has been ignored as insignificant compared to the other forms of network delay. However, in some systems, the processing delay can be quite large especially where routers are performing complex encryption algorithms and examining or modifying packet content. Deep packet inspectiondone by some networks examine packet content for security, legal, or other reasons, which can cause very large delay and thus is only done at selected inspection points. Routers performingnetwork address translationalso have higher than normal processing delay because those routers need to examine and modify both incoming and outgoing packets.

2. Queuing delay : In aswitched network, thetimebetween the completion ofsignalingby thecall originatorand the arrival of a ringingsignalat thecall receiver.Queues may be caused by delays at the originatingswitch, intermediate switches, or the call receiver servicing switch.In apacket-switched network, the sum of the delays encountered by a packet between the time of insertion into the network and the time of delivery to the addressee. 3. Transmission delay : In a network based on packet switching, transmission delay (or store-and-forward delay) is the amount of time required to push all of the packet's bits into the wire. In other words, this is the delay caused by the data-rate of the link.

Transmission delay is a function of the packet's length and has nothing to do with the distance between the two nodes. This delay is proportional to the packet's length in bits,

It is given by the following formula:

DT = N / Rwhere

DT is the transmission delayN is the number of bits, andR is the rate of transmission (say in bits per second)Most packet switched networks use store-and-forward transmission at the input of the link. A switch using store-and-forward transmission will receive (save) the entire packet to the buffer and check it for CRC errors or other problems before sending the first bit of the packet into the outbound link. Thus store-and-forward packet switches introduce a store-and-forward delay at the input to each link along the packet's route.4. Propagation delay: Propagation delay is defined as the amount of time it takes for a certain number of bytes to be transferred over a medium. Propagation delay is the distance between the two routers divided by the propagation speed.

Propagation delay = d/s where d is the distance and s is the speed.

In electronics, digital circuits and digital electronics, the propagation delay, or gate delay, is the length of time starting from when the input to a logic gate becomes stable and valid, to the time that the output of that logic gate is stable and valid. Often this refers to the time required for the output to reach 50% of its final output level when the input changes. Reducing gate delays in digital circuits allows them to process data at a faster rate and improve overall performance.A fully connected network, complete topology, or full mesh topology is a network topology in which there is a direct link between all pairs of nodes. In a fully connected network with n nodes, there are n(n-1)/2 direct links. Networks designed with this topology are usually very expensive to set up, but provide a high degree of reliability due to the multiple paths for data that are provided by the large number of redundant links between nodes. This topology is mostly seen in military applications.

Ans.5. Centralised Network: A type ofnetworkwhere all users connect to a central server, which is the acting agent for all communications. This server would store both the communications and the user account information. Most publicinstant messagingplatformsuse a centralized network. Also calledcentralized server-structure. A centralized network will contain a single method of control for the entire network. A centralized network will typically have only one server. However, some centralized networks may use two or more servers but each submits to one central point of control. Centralized networks possess many benefits, such as the elimination of duplicate processes across many servers. However, if poorly maintained, a centralized server may run slowly or perform poorly.Distributed Network: A distributed network is a type of computer network that is spread over different networks. This provides a single data communication network, which can be managed jointly or separately by each network. Besides shared communication within the network, a distributed network often also distributes processing. A distributed network is powered by network management software, which manages and monitors data routing, combining and allocating network bandwidth, access control and other core networking processes.Distributed networks and processing work together to deliver specialized applications to different remote users. This means that an application may be hosted and executed from a single machine but accessed by many others. A client/server computing architecture is an example of a distributed network where the server is the producer of a resource and many interconnected remote users are the consumers who access the application from different networks.

Assignment BAns.1. An RMA (return merchandise authorization) is a numbered authorization provided by a mail-order merchant to permit the return of a product. Most mail-order businesses have a policy concerning returns. Some companies allow only defective products to be returned; others allow any software to be returned if it is unopened.RMA numbers are important to both the merchant and customer. An RMA number tells the merchant that a return is being made and offers protection against fraudulent returns. The customer can use the RMA number to inquire on the progress of a return. For example, if the customer hasn't received any information about the return, the customer can call the merchant and use the RMA number as a reference.Common Availability Definitions:1. Availability = MTBF/(MTTR+MTBF) (Mean Time Between Failure, Mean Time To Recover). This is a classic definition of availability and is often used by hardware manufacturers when they publish an availability metric for a given server.2. Availability = (Uptime + Scheduled Maintenance)/(Unscheduled Downtime + Uptime + Scheduled Maintenance). This is an IT centric availability metric where the business can support scheduled downtime after hours. This model works for some types of systems, such as a file server that isnt needed at night, but it doesnt work as well for websites, even though many web companies still use this for their SLAs.3. Availability = Uptime/(Uptime + Downtime). This metric best applies to systems that are needed 247 such as e-commerce sites.Availability is most often expressed as a percentage. Sometimes, people will refer to four nines (99.99%) or five nines (99.999%).If for a network system MTBF is 5 unit time and MTTR is 1 unit time then the availability is 0.83 or 99.990%.Ans.2. Atrade-off(ortradeoff) is a situation that involves losing one quality or aspect of something in return for gaining another quality or aspect. More colloquially, if one thing increases, some other thing must decrease.The idea of a tradeoff often implies a decision to be made with full comprehension of both the upside and downside of a particular choice.The objective of the time-cost trade-off analysis is to reduce the original project duration, determined form the critical path analysis, to meet a specific deadline, with the least cost.In general, there is a trade-off between the time and the direct cost to complete an activity; the less expensive the resources, the larger duration they take to complete an activity. Shortening the duration on an activity will normally increase its direct cost which comprises: the cost of labor, equipment, and material. It should never be assumed that the quantity of resources deployed and the task duration are inversely related. Thus one should never automatically assume that the work that can be done by one man in 16 weeks can actually be done by 16 men in one week.Ans.3. The central element of the system is a server, which provides some service to items. Items from some population of items arrive at the system to be served. If the server is idle, an item is served immediately. Otherwise, an arriving item joins a waiting line2. When the server has completed serving an item, the item departs. If there are items waiting in the queue, one is immediately dispatched to the server. The server in this model can represent anything that performs some function or service for a collection of items. Examples: a processor provides service to processes; a transmission line provides a transmission service to packets or frames of data; an I/O device provides a read or writes service for I/O requests. In fact, the lower line is based on fitting a third-order polynomial to the data available up to a load of 0.5. The waiting line is referred to as a queue in some treatments in the literature; it is also common to refer to the entire system as a queue. Unless otherwise noted, we use the term queue to mean waiting line. A good example to think about for intuition is an ATM machine. We view the machine as a server that serves customers one at a time. The customers arrive randomly over time and wait in a queue (line), and upon beginning service, each customer spends a random amount of time in service before departing.

Little's law, which states the linear relationship between average queue length and average waiting time in the queue. In particular, the expected relationship is as follows:Average queue length = (Mean arrival rate)(Average waiting time in queue)The FIFO Queue block computes the current queue length and average waiting time in the queue. The subsystem called Little's Law Evaluation computes the ratio of average queue length (derived from the instantaneous queue length via integration) to average waiting time, as well as the ratio of mean service time to mean arrival time. The two ratios appear on the plot labeled Arrival Rate: Theoretical vs. Simulation Results.Another way to interpret the equation above is that, given a normalized mean service time of 1, you can use the average waiting time and average queue length to derive the system's arrival rate.The linear relationship that Little's law predicts between the server utilization and the average service time. The Single Server block computes the server utilization and average waiting time in the server. Because each entity can depart from the server immediately upon completing service, waiting time is equivalent to service time for the server in this model.

Assignment C1. During the analysis phase, the project team: a) describes the functional features of the system chosen for development in the previous phase b) studies the organization's current procedures and the information systems used to perform organizational tasks c) determines the scope of the proposed systems and produces a specific plan for the proposed project d) codes, tests, and installs the new system

2. Network analysis, architecture, and design are processes used to produce designs that are logical a) logical b) reproducible c) defensible d) All of the above

3. Network design is also about applying a) the trade-offs b) dependencies c) constraints developed as part of the network architecture. d) All of the above

4. The various sources of delay are a) propagation, b) transmission, c) queuing d) None of the above

5. Which of the following are performance characteristics of Services? a) Capacity b) Delay c) RMA. d) All of the above

6. The post implementation phases of a networks life cycle can be broken into a) operations b) Maintenance c) human knowledge d) None of the above

7. The key characteristics of a network architecture and design that affect the post implementation costs are a) Network and system reliability b) Network and system maintainability c) Training of the operators to stay within operational constraints d) All of the above

8. The terms are associated with capacity are a) Bandwidth b) throughput, c) goodput. d) All of the above

9. A threshold is a value for a) a performance b) a delay c) a reliability d) none of the above

10. The network behaviour describes with help of a) delay (end-to-end and round-trip) b) latency c) delay variation d) All of the above 11. Devices can act as both data sources and sinks, depending on the application and flow. Which of the following devices (for the applications given) are data sinks? Data sources? a) A storage device receiving streaming video from a camera b) A video editing unit, using video from the storage device in (a) c) A Web server and its clients d) A storage disk farm

12. Which flow models apply to each set of flows described below? a) Users on the Internet accessing the same Web server b) Forty workstations processing batch jobs overnight, managed by a central mainframe c) Email use across the Internet d) A transaction-processing application, authorizing credit card transactions between a companys retail stores and its headquarters

13. Flow specifications describe flows a) best-effort b) predictable c) guaranteed requirements d) All of the above

14. Flow model based on the relationship between a) the task manager b) the computing devices c) what the task is d) None of the above

15. Some common approaches to identifying flows include: a) Focusing on a particular application b) application group c) device or function d) None of the above

16. Flows are becoming increasingly important in the fields including a) Analysis b) Architecture c) design processes d) Data process.

17. Flow specification has a different level of detail, based on whether the flows have a) best-effort b) predictable c) guaranteed requirements. d) All of the above

18. A service plan describes network performance in terms of a) Capacity b) Delay c) RMA d) All of the above

19. The primary characteristics of flow models are a) Directionality b) Hierarchy c) diversity d)All of the above

20. The most favourable solution to non-uniform demand is probably to: a. Always maintain excess capacity b. Hire or lay off workers as required c. Use overtime or part-time workers d. Employ a mixed capacity management plan

21. Capacity is usually expressed in terms of: a. The Master Production Schedule b. A production forecast c. Potential output from an operations system d. The design life of an operations process

22. The maximum output of a system in a given period is called: a. The designed capacity b. The master production schedule c. The economic order quantity d. The production efficiency

23. The first steps of capacity planning and control do not include: a. Measuring aggregate demand and capacity? b. Identifying the alternative capacity plans? c. Studying the effect of queueing theory d. Choosing the most appropriate capacity plan?

24. Which of the following is not one of the assumptions of an M/M/1 model? a) Arrivals are independent of preceding arrivals but the arrival rate does not change over time. b) Arrivals are served on a last-in, first-served basis. c) Service times follow the negative exponential probability distribution. d) Arrivals follow the Poisson distribution and come from an infinite population.

25. The utilization factor for a system represents a) the steady state average waiting time. b) the probability that no one is in the system. c) the probability that the service facility is being used. d) the average number of customers in the queue.

26. At the start of football season, the ticket office gets very busy the day before the first game. Customers arrive at the rate of four every ten minutes. The customer would be better off if the stadium employed a) a single ticket seller who could service a customer in two minutes. b) two ticket sellers each of whom could service a customer in three minutes. c) The two situations produce the same wait times. d) All of the above.

27. The minimal-spanning tree technique would best be used a) by an architect to lay out corridors between offices in a new office building. b) by a telephone company attempting to lay out wires in a new housing development. c) by an airline laying out flight routes. d) all of the above.

28. The maximal-flow technique might be used a) to help design the moving sidewalks transporting passengers from one terminal to another in a busy airport. b) by someone designing the traffic approaches to an airport. c) by someone attempting to design roads which would limit the flow of traffic through an area. d) all of the above.

29. Small size network problems can usually be solved by a) the simplex method. b) Inspection. c) calculus and advanced sophisticated techniques. d) none of the above

30. A tree is a) any graph that is connected and every edge is a bridge. b) any graph that has no circuits. c) any graph with one component. d) any graph that has no bridges.

31. The Gantt Chart is used to: a) control cost of all the activities. b) provide a schedule of the activities . c) track the cost of the activities. d) provide a schedule and track costs of activities.

32. The critical path in a network of activities: a) will be the path with the most number of activities. b) must have at least three activities. c) will always have all activities with positive slack. d) cannot be delayed or else the entire project will be delayed.

33. Which of the following statements is true? a) PERT and CPM are both probabilistic techniques. b) PERT is considered as a probabilistic techniques and CPM is considered as a deterministic approach. c) PERT and CPM are both considered as deterministic approaches. d) PERT is considered as a deterministic approach and CPM is a probabilistic techniques.

34. The immediate predecessors of any node in a project network drawn as a AON diagram : a) may be one or more node(s). b) may be two or more nodes. c) is always only one node. d) may be no nodes to many nodes.

35. The standard deviation for a PERT diagram is calculated by: a) taking the sum of the standard deviations on the nodes on the critical path. b) taking the sum of the variances on the nodes on the critical path, then find the square root. c) taking the sum of the variance on all the nodes, then find the square root. d) taking the sum of the standard deviations on all the nodes.

36. Which of the following can shorten the duration of an activity or project? a) Overtime b) Subcontracting c) Hiring extra labour d) All answers are correct.

37. Which of the following statements is true? a) The EFT for an activity is equal to the EST minus the slack for that activity. b) Dummy activities do not require any resources. c) When considering the possible crashing of a project, the normal time equals the length of the shortest path prior to any crashes. d) For the beta distribution, m will always be exactly in the middle of a and b.

38. An expected project completion time follows a normal distribution with a mean of 21 days and a standard deviation of 4 days. What is the probability that the project will be completed in a time between 22 to 25 days inclusive? a) 0.8413 b) 0.7734 c) 0.0819 d) 0.2426

39. The latest finish time for an activity: a) equals the min. of LFT - t for all immediate successors. b) equals the min. of EST + t for all immediate successors. c) equals the max. of LFT - t for all immediate predecessors. d) equals the max. of EST + t for all immediate predecessors.

40. Which of the following statements is true? a) The variance of the time taken to complete an activity is equal to (b - a)/6. b) Three time estimates are necessary so that we can estimate the parameters of the Beta distribution. c) The standard deviation of a project completion time is the sum of the standard deviations for the critical path activities. d) The critical path is the path with the largest probability of being completed on time