...Department, Institute Eur´ com, e 06560 Sophia-Antipolis, France, Email: {gesbert, kiani}@eurecom.fr maximize the network capacity for the case of individual link power constraints [8] and a sum power constraint [9]. In [10] it is assumed that each base station, when it transmits, transmits with maximum power Pmax . Which base stations that should be active at each time slot is decided according to a rate maximization objective. However, no proof of optimality is given for the on/off power allocation. In [11] transmit power allocation for a downlink two-user interference channel is studied under a sum transmit power constraint and the assumption of symmetric interference. The derived power allocation depends on the level of interference; when the inference is above a certain threshold the total power is allocated to the best user. For interference less than the threshold, the available power is divided among the two users according to a water-filling principle. However, due to the sum power constraint and symmetry of interference assumption these results are not readily applicable for two-cell power allocation, where it is more reasonable to assume individual power constraints and that the received interference will be different for different users. In this paper we tackle the problem of analytically finding a closed form solution for power allocation in a simple two-cell network, without resorting to the restricting assumptions of interference limiting or symmetry. The optimal power allocation...
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...¨ TECHNISCHE UNIVERSITAT BERLIN Fakult¨t IV – Elektrotechnik und Informatik a Fachgebiet Intelligente Netze Prof. Anja Feldmann Juhoon Kim, Franziska Lichtblau, Arne Ludwig, Philipp Richter, Florian Streibelt 10th Assignment: Network Protocols and Architectures, WS 13/14 Question 1: (20 points) Fairness of TCP: AIMD vs. AIAD Refer to the figure on the right which illustrates the convergence of TCP’s additive-increase, multiplicative-decrease (AIMD) algorithm. The figure shows the throughput by the two TCP connections 1 and 2. Suppose that instead of a multiplicative-decrease TCP decreases the window size by a constant amount. Would the resulting additive-increase, additive-decrease converge to an equal share algorithm? Justify your answer using a diagram similar to the figure on the right. Full bandwidth utilization line Equal bandwidth share Connection 2 throughput D B E C A Connection 1 throughput Question 2: (10 points) Resource Allocation: Congestion Control Discuss how the Internet would look like if every flow would be based on UDP and does not use congestion control. Question 3: (10 points) Security of ARP Explain the principle of ARP spoofing and discuss a way to defend against it. Question 4: (10 points) Switching Loops For redundancy reasons it might be a good idea to have a switch connected to several switches instead of only one. Have a look at the Figure below and explain why it can cause problems having switches S2 and S3 connected to both switches...
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...average waiting time pair to retransmission is 50 µs. a) Calculate delay as a function of ρ. b) Plot D vs ρ. Q2 500 users employ TDMA to transmit 1000 bit packets of data. The channel bandwidth is 100 MHz and QPSK is employed. a) What is the max is the maximum allowable bit rate in the channel? b) What is the packet rate? c) What is the frame time – the time taken to transmit the packet from each user? Q3 a) Plot the throughput for CSMA as given by eq 16.4.35 as a function of TD/ TP for ρ = 0.25. b) At what value of TD/ TP , would slotted ALOHA field a higher throughput? Q4 Assuming that packet transmission and retransmission can both be described as a Poisson process. Calculate the probability that a data packet transmission in slotted ALOHA system will experience a collision with one other user. Assume that the total traffic rate λ = 10 packets/sec, Tp = 10 ms. Q5 Measurements of a slotted ALOHA channel shows that 20% of the slots are idle. a) What is the normalized total traffic in the channel? b) What is the normalized throughput? Q6 A TDMA system operates at 100 Mb/s with a 2ms frame time. Assume that all slots are of equal length and that a guard time of 1µs is required between slots. a) Compute the efficiency of the communication source for the case of 1, 10, and 100 slots per frame. b) Repeat above plot a) assuming that a 100 bit preamble is required at the start of each slot. Compute efficiency of communication source. --------------------------------------...
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...that we have the ability to increase sales and profitability. Given the expansion of the market and competitive position, it is my feeling that we have missed certain opportunities to grow. I do not know if our government system has been to discourage managers to adhere to the objectives of the company, which is growing fast and being above average ROA compared with other companies in the industry. I want you to have it in mind when you are evaluating our system. proliferation Metal industry Metal Service Centers purchase from many factories (e.mills), including USX, Bethlehem, Alcoa, Reynolds and smaller companies like Crucible, Northwestern and Youngstown . These suppliers sell products in large batches. By doing this they maximize the throughput capacity of large production end collisions (e.run). Service Centers sells its consumers in smaller batches and shorter processing time. The distribution of metal industry was generally considered of mature, highly competitive and sundering industry. Still has a lot of firsts in the industry who have given Service Centers opportunity to grow. cuts in steel plant in their effort to be more competitive by increasing production capacity, most large national metal manufacturers have been withdrawn product lines by skip specialty produced in limited quantities. Also, they had to reduce service to customers by reducing the salesforce size and technical services. Full-line service centers, have noticed that many of their customers prefer to do...
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...are 70% of all berries. D. Holding bins 17-24 are dedicated to wet berries. E. Capacity of each of five dumpers is 600 bbl/hr. F. When holding bins for wet berries are full, the Kiwanee dumpers are not available to process wet berries, i.e., dumpers cannot temporarily store any wet berries. G. There are 20 peak days in one year, where there is truck waiting happened. H. Truck Drivers are paid by $18/hr Submitted questions: 1. Analyze the current process. [Using the process flow map, available in the Excel file associated with the assignment, of the current process at Receiving Plant #1, mark the capacity of each of the activities. Show the flows of wet and dry berries separately.] 2. On a busy day, what is RP#1’s current maximum throughput rate? 3. Assuming that processing starts at 7 am on a “busy” day, present the situation during such a day, by constructing an inventory build-up diagram for bins and trucks. 4. What are the possible capital investments considered by NCC? 5. Quantify the costs and benefits for NCC’s investment for the fifth Kiwanee dumper in 1980. 6. Quantify the costs and benefits of “converting dry berry holding bins into wet/dry berry holding bins.” Requirements for submitted...
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...operations. We performed some analysis in Excel and created a dashboard to illustrate various data. Specifically, we regressed the prior 50 days of jobs accepted to forecast demand over the next 2 - 3 months within a 95% confidence interval. The yellow and grey lines represent the maximum and minimum variability, respectively, based on two standard deviations (95%). Exhibit 1: Forecasted and actual demand by Day 50 and Day 270 Our two primary goals at the beginning of the simulation were as follows: 1) Eliminate bottlenecks and increase capacity in order to meet forecasted demand 2) Decrease lead time to 0.25 days in order to satisfy Contract 2 and maximize revenue In order to achieve these goals, we would need to know the capacity and throughput time of the entire system. We used the time required by each machine to process a lot to calculate capacity per station and then capacity of the entire production line (380 kits/day or 6 orders/day). In Exhibit 2 we can observe that the capacity of the production line is given by the station that produces the least number of units per day. Exhibit 2: Capacity of the production line The Decisions We decided to work with the maximum variability of demand because there was a penalty for late jobs and because there was no revenue for orders that took more than “x” days. Since the simulator runs at a rate of 34 simulated days per each real day, we had to estimate the demand for the following 34 days. Day 1 We identified the bottleneck...
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... * How much growth is this network going to have to support? When planning for this, you want to make sure that the company is going to have room to grow, which may vary depending on the company. For example, Target is probably going to be a faster growing network than a local mom/pop shop. * Availability * How long your network is available to users. Basically: is your network and up and running all day, every day? * Network Performance * This includes categories that measure the throughput of data and how efficient your network actually is. (Optimum Utilization) * Security * Security design is one of the most important aspects of a network. Without proper security your network is vulnerable to online cyber attacks that can cripple and steal from your databases. * Manageability * This technical goal is going to vary based on company needs. Some customers are going to have more precise goals. The book talks about a company planning to record the number of bytes sent and received to each router. Other clients may have less specific goals than this, it just tends to vary based on company objectives. * Usability * Close to manageability, but different. Usability refers to people who are accessing and using the network you have setup. Your network needs to be easy to use for them (different from management. Easier To Use =/= Easier To Manage) * Adaptability * Design the network so that in can accept new technologies...
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...Case Report: National Cranberry Cooperative Fill in your name in the header. Please read the Assignment Collaboration Guidelines in Course Syllabus: Collaboration between groups is not allowed; however, if you hear something from some other group, please give a reference. Below, write your answers to Questions 1-4 (on BB/Cases). Your analysis should be based on the assumptions listed in the Syllabus. If you need to make additional assumptions to answer a question, clearly state them, logically defend them, and then proceed to answer the question accordingly. The idea is to answer the questions concisely. Double spacing is preferred, 1.5-line spacing is the minimum (consider the reader’s eye strain). 1. Analyze the current process. Using the process flow map (available on CTools) of the current process at Receiving Plant No.1, mark the capacity and utilization of each of the resources. Show the flows of wet and dry berries separately. First we receive 18,000 barrels over a 12 hour period which leads to a 1,500 bbl/ Hr, Then 75% of 1,500 total berries per hour equal 1,125 bbl/Hr and the remaining 25% or 375 bbl/Hr are dry berries. While our Dumper is holding a capacity of 3,000 bbl/Hr and utilizing only the 1,500 bbl/Hr we are receiving. Those berries would then split up in the dry and wet storage bins. Dry bins have a capacity of 4,000 bbl/Hr which is 16 bins holding 250 bbl/Hr each. Whereas the wet bins kept a storage capacity of 3,200 with 8 bins holding 250 bbl/Hr...
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...Learning Objectives Network Design and Management ITT550 Chapter 2: Business & User Requirements 2 List the most important business requirements to gather. Explain the difference information providers and decision makers. Describe some of the business costs of a network failure. List three methods of gathering user requirements. Describe ways to derive technical requirements from non-technical user comments. [Credit to Shapina and Pricislla for their materials.] Requirements from the Business Perspective 3 4 Business Requirements These include: Key Players Major Milestones Funding Levels Types of Business Activity Estimated growth Reliability and Availability Security Web site and Internet connectivity Remote Access Must understand the nature of the business that will use it. If you design a network for your company it is easier for you to match network requirements with business strategy. If not, you need to conduct interview with management and key personnel. 1 Business Requirements: Key Players 5 Business Requirements: Major Milestones 6 Know who to ask. Identify key players & key groups from organization chart. 2 types of key players: Information sources – explain business strategies, long-term plans, business requirements. Decision makers – approve overall network design or establish funding levels. Normally information sources & decision makers are from the same person. However, it can be from different person. Key factor - Timing....
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...Top-Down Network Approach as outlined by CISCO. • Analyze Requirements • Logical Network Design • Physical Network Design • Testing, Optimizing, and Documenting the Network Design 2. Briefly explain each of the following terms. a. Reliability : Reliability is an attribute of any computer-related component (software, or hardware, or a network) that consistently performs according to its specifications. b. Availability : A measure of how much time a network or a connection is running. c. Efficiency : Accomplishment of or ability to accomplish a job with a minimum expenditure of time and effort d. Delay : The interval of time between sending and receiving of data. e. Accuracy : Data received are exactly match with data sent. 3. Differentiate between Bandwidth, Throughput and Goodput. BW: The amount of data that can be transmitted in a fixed amount of time TP: The quantity of error free data transmitted in amount of time GP: Goodput can be described as measuring the throughput at the application level (without the over head) 4. What do you understand of “Making a tradeoff” in analyzing technical goals during analyzing requirements of new network design? Giving up one advantage in order to gain another and in networking it is measured in percentage. 5. Name ANY THREE (3) types of traffic flow in characterizing network traffic...
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...Home Network Speed Name Wilmington University INTRODUCTION- The Speed test was carried out for my home network through the period from 8/31/15 to 10/13/2015. Various screen shots were taken, and with the help of them, the graph was plotted. The different type of the network pattern was seen. The different changes were found while performing these tests. The jitter shown variations from 17 to 175 ms. One of the reason for this cause is network congestion. It can be at the router interfaces or in a provider or carrier network if the circuit has not been provisioned correctly. There is a variation in ping from 11 to 14 ms. As the there is inadequate bandwidth a ping becomes variable. In addition, the speed claimed by Comcast is 100mbs but it showing minimum speed of 4.60 mbps and maximum of 13.25 mbps. ANALYSIS: With the graph's assistance, I can watch the general pattern of net index and unpredictable values of ping and jitter for my home system. My ISP is Comcast. As indicated by this chart, I can say that Comcast is not ready to satisfy the speed that was guaranteed for my agreement. Variations of Ping and Jitter prompts lessened reaction both for upload and download speeds. I have utilized different devices, for example, Smartphone, three tablets to the same modem/switch that made the heap on my home system. Particularly amid evening time and late evenings, I have seen a drop in the speed. I think my plan ought to be checked that will help me to get great speed for what...
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...1 OBJECTIVES.............................................................................................................Page 3 1.2 INTRODUCTION......................................................................................................Page 4 1.3 EQUIPMENTS USED............................................................................................... Page 4 CHAPTER TWO 2.0 METHODS AND PROCEDURES............................................................................Page 5 2.1 PRESENT NETWORK OVERVIEW........................................................................Page 5 2.2 MAIN OFFICE NETWORK......................................................................................Page 7 2.3 SUBNET OFFICE NETWORK.................................................................................Page 7 2.4 BUSY NETWORK SCENARIO...............................................................................Page 7 CHAPTHER THREE 3.0 PROPOSED NETWORK SCENARIO......................................................................Page 9 3.1 TECHNICAL ANALYSIS.........................................................................................Page 9 3.2 DISCUSSIONS.........................................................................................................Page 13 3.3 ESTIMATED COST.................................................................................................Page 13...
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...Team 3 National Cranberry Cooperative Analysis and recommendations 1. 2. The resource with least capacity determines the maximum long-term achievable throughput rate. Because wet and dry berries follow different routes at RP#1 there will be a maximum achievable throughput for each. The capacity of the dryers is the bottleneck for the wet berries. The maximum throughput for wet berries is 600 bbls/hr. For dry berries the separation process is the bottleneck. The maximum throughput for dry berries is 1200 bbls/hr. The percentage of wet berries to dry berries would affect the throughput rate. Given the current proportion of berries received the capacity of the dryers would be the maximum throughput of the system. The dryers are the system bottleneck. And as the trend of water harvesting continues, this situation worsens. All the process/resources at RP#1 contribute to the throughput but the limitation is the bottleneck. 3. The trucks wait because the processing capacity is less than the system input. And the temporary holding bins are inadequate to buffer the berries coming in and the plants processing capacity. But by using the Theory of Constraints to identify the system bottle necks we are able to discover the root cause of the waits. The large back log of berries is caused by several factors The plant is not currently equipped to handle the supply of wet berries. This problem has likely been increasing over the years as more cranberries are being...
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...Network Administrator This position reports to the IT Service Desk Manager and is responsible for the IT infrastructure of the Direct Sale Distribution (DSD) facilities within the company; the position will assist the Corporate Network administrator when needed in the operation of corporate and manufacturing facilities. The scope of responsibility will include reviewing the system needs of the organization and aid in developing a road map to enhance applications, infrastructure, support, and end-user training; act as an advisor to the operating committee for technology and business related matters, and will ultimately be responsible for quality of the services that are delivered. This position will work with management to help establish and direct strategic long term goals, policies and procedures for the company’s information technology function. As well as, being responsible for developing and assisting the IT Service Desk Manager with the annual capital budgets, this position will focus on acquiring and deploying the hardware and software required to support the company’s short term and long range goals. Key Responsibilities and Accountabilities • Establishes network design and strategies by evaluating network performance issues including availability, utilization, throughput, goodput, and latency. • Planning and executing the selection, installation, configuration, and testing of equipment. • Define network policies and procedures, establishing connections...
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... forgetting your sunscreen may lead to a painful burn, but forgetting key components of a network virus security plan hurts a lot more. Overlooking even one item can weaken your entire network and mean significant losses in revenue and productivity. This paper will discuss the connection between corporate and home-use antivirus software along with the roles of top management/non-IT management, IT professionals, and end-users in maintaining network security. It will also discuss other issues which routinely arise that could affect the network security of our corporation. Antivirus software is a computer program that attempts to identify, neutralize or eliminate malicious software. The term "antivirus" is used because the earliest examples were designed exclusively to combat computer viruses; however most modern antivirus software is now designed to combat a wide range of threats, including worms, phishing attacks, rootkits, and Trojans, often described collectively as malware. Even though this software protects against certain threats, it does not protect against ALL threats. Fortunately, there are signature files and updates created daily that will allow the latest threats to be neutralized. Robert Vamosi states that it is important for corporate clients to protect their networks and therefore pay for the software and the annual signature-file subscriptions to ensure network operations (Vamosi, 2004) and I agree. Additionally, if antivirus were made available free...
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