Are there cases where a network sniffer is a legitimate application to be running? What operating systems will support a packet-sniffing application? Name four Linux-based packet sniffers.

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Text Book1: Chapter 4

You should be submitted in Blackboard CTEC445\ HW4: See: Due Date in Blackboard

Part1: Grade (10 points)

  1. Are there cases where a network sniffer is a legitimate application to be running?
  2. What operating systems will support a packet-sniffing application?
  3. Name four Linux-based packet sniffers.
  4. Name four Windows-based packet sniffers.
  5. What is a good way to keep sniffer technology from discovering your e-mail passwords?
  6. What protocol would you consider for encrypting passwords?
  7. What does a time domain reflectometer do?
  8. What are the components of an average packet sniffer?
  9. What is a MAC address?
  10. What equipment uses a MAC address?
  11. What feature of a NIC on a TCP/IP network does a sniffer exploit?

 

Discuss at least three of the models. Identify each of their respective advantages and disadvantages.

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Traditional software processing models

This discussion forum focuses on traditional software processing models used by developers to create a successful system. Discuss at least three of the models. Identify each of their respective advantages and disadvantages.

 

Calculate the effective access time for a demand-paged memory given a memory access time of 100 nanoseconds, a page fault service time of 6,000,000 nanoseconds, and a page-fault rate of 1 page fault out of every 10,000 access attempts.

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Virtual Memory Template

Instructions

Consider a demand-paging system with the following time-measured utilizations:

  • CPU utilization 20%
  • Paging disk 97.7%
  • Other I/O devices 5%

For each of the following, say whether it will (or is likely to) improve CPU utilization. Explain your answers.

  1. Install a faster CPU.
  2. Install a bigger paging disk.
  3. Increase the degree of multi programming.
  4. Decrease the degree of multi programming.
  5. Install more main memory.
  6. Install a faster hard disk or multiple controllers with multiple hard disks.
  7. Add preparing to the page fetch algorithms.
  8. Increase the page size.
  9. What is the cause of thrashing?
  10. How does the system detect thrashing?
  11. Once it detects thrashing, what can the system do to eliminate this problem?
  12. A system provides support for user-level and kernel-level threads. The mapping in this system is one to one (there is a corresponding kernel thread for each user thread). Does a multithreaded process consist of (a) a working set for the entire process or (b) a working set for each thread? Explain.
  13. Consider the following page reference string:

7, 2, 3, 1, 2, 5, 3, 4, 6, 7, 7, 1, 0, 5, 4, 6, 2, 3, 0, 1.

Assuming demand paging with 3 frames, how many page faults would occur for the following replacement algorithms?

  1. LRU replacement

Answer:

 

  1. FIFO replacement

Answer:

 

  1. Optimal replacement

Answer:

 

  1. 7. Calculate the effective access time for a demand-paged memory given a memory access time of 100 nanoseconds, a page fault service time of 6,000,000 nanoseconds, and a page-fault rate of 1 page fault out of every 10,000 access attempts. You must show your calculations to receive full credit on this question.

 

  1. Using the following page replacement algorithms, determine the number of faults in the following reference string given a physical memory size of 4 frames:

5  6  5  4  4  4  8  2  9  9  0  4  5  3  9  6  8  1  9  1  6  1  0  0  5

 

Replacement algorithm 3 frames
a.       FIFO  
b.      OPT  
c.       LRU  
d.      LFU  
e.      MFU  

 

Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for each of the following disk-scheduling algorithms?

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Mass Storage Template

  1. Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. The drive is currently serving a request at cylinder 2,150, and the previous request was at cylinder 1,805. The queue of pending requests, in FIFO order, is:

2,069   1,212   2,296   2,800   544      1,618   356      1,523   4,956   3,681

Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for each of the following disk-scheduling algorithms?  Record your answers in the table below.

  Question 1: Total Distance Question 2 (a): Total Seek Time
a.       FCFS    
b.      SSTF    
c.       SCAN    
d.      LOOK    
e.      C-SCAN    
f.        C-LOOK    

 

  1. Elementary physics states that when an object is subjected to a constant acceleration a, the relationship between distance d and time t is given by d = ½ at2. Suppose that, during a seek, the disk in Question 1 accelerates the disk arm at a constant rate for the first half of the seek, then decelerates the disk arm at the same rate for the second half of the seek.  Assume that the disk can perform a seek to an adjacent cylinder in 1 millisecond and a full-stroke seek over all 5,000 cylinders in 18 milliseconds.

We can express an equation for the seek time as a function of the seek distance.  This equation should be of the form t = x + y , where t is the time in milliseconds and L is the seek distance in cylinders.  First, we solve the simultaneous  equations t = x+y  that result from (t = 1, L =1) and (t =18, L =4999) to obtain

t =0.7561+0.2439 . 

Using this equation, perform the following calculations:

  1. Calculate the total seek time for each of the schedules in Question 1.

 

(Note that you have to calculate the individual distances for each access, apply the formula to them, then add them all up to get the total seek time for each method.)  Record your answers in the table above.

 

  1. The percentage speedup is the time saved divided by the original time. What is the percentage speedup of the fastest schedule over FCFS?  To receive full credit for this question, you must show your calculations.

Answer:

 

Compare and contrast the major differences between IPv4 and IPv6. Your write-up should include: how decisions are made, how addresses are assigned.

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Lab Challange 07

Compare and contrast the major differences between IPv4 and IPv6. Your write-up should include the following details:

-Header details
-Datagram size
-How decisions are made
-How addresses are assigned
-Responses should be at least 400 words.

Analyze an existing dataset. Create a mathematical model for a network. Identify and tackle practical problems in networked systems, ideally with data science related techniques learned from the above material from Chiang 2012.

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Networked Life

Based on the material on Chapter 1 to 4 of:

Mung Chiang, “Networked Life: 20 Questions and Answers”, Cambridge University Press, 2012

(file “NetworkedLife.PDF”)

Working on network application or data service projects

Create a network (e.g., build an app)

Measure/describe a network (one we don’t look at)

Analyze an existing dataset (e.g., discussion forum posts)

Create a mathematical model for a network (e.g., people posting on TikTok)

The students are expected to identify and tackle practical problems in networked systems, ideally with data science related techniques learned from the above material from Chiang 2012.

 

Do some research on both CSMA/CD and CSMA/CA. Explain how they function and how they both operate in the real world. Provide two examples of CSMA/CD and CSMA/CA.

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Lab Challange 05

Do some research on both CSMA/CD and CSMA/CA. Explain how they function and how they both operate in the real world. Provide two examples of CSMA/CD and CSMA/CA.

Explain, through an example, the support given to decision makers by computers in each phase of the decision process.

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Decision-making process

Saudi Electronic University is considering opening a branch in UAE. List typical activities in each phase of the decision (intelligence, design, choice, and implementation) regarding whether to open a branch.

  1. Explain, through an example, the support given to decision makers by computers in each phase of the decision process.

Some steps in (a) can be supported by AI technology. Describe how AI technology can assist those steps and how it enriches the decision-making process

 

 

How many bits are required in the logical address? Explain how you arrived at this solution. How many bits are required in the physical address? Explain how you arrived at this solution.

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Main Memory Template

  1. Assuming a 1-KB page size, indicate the page numbers and offsets for the following address references (provided as decimal numbers) in the table below:
Address Reference Page Offset
  1. 3085
    
  1. 42095
    
  1. 215201
    
  1. 650000
    
  1. 2000001
    

 

  1. Consider a logical address space of 256 pages with a 4-KB page size, mapped onto a physical memory of 64 frames.
  1. How many bits are required in the logical address? Explain how you arrived at this solution.

Answer: ____________________________

Explanation:

 

  1. How many bits are required in the physical address? Explain how you arrived at this solution.

Answer: ____________________________

Explanation:

 

  1. Consider the following segment table:
Segment Base Length
0 219 600
1 2300 14
2 90 100
3 1327 580
4 1952 96

 

What are the physical addresses for the following logical addresses?

Logical Addresses Physical Addresses
  1. 0,430
  
  1. 1,10
  
  1. 2,500
  
  1. 3,400
  
  1. 4,112
  

 

  1. Consider a paging system with the page table stored in memory.
  1. If a memory reference takes 50 nanoseconds, how long does a paged memory reference take? Explain how you arrived at this solution.

Answer: ______________________________________________________

  1. If we add TLBs, and 75 percent of all page-table references are found in the TLBs, what is the effective memory reference time? (Assume that finding a page-table entry in the TLBs takes 2 nanoseconds, if the entry is present.) You must show your calculations to receive full credit.

Answer: ______________________________________________________

  1. Given six memory partitions of 300 KB, 600 KB, 350 KB, 200 KB, 750 KB, and 125 KB (in order), how would the first-fit, best-fit, and worst-fit algorithms place processes of size 115 KB, 500 KB, 358 KB, 200 KB, and 375 KB (in order)? First-fit is already done for you as an example.
  2. First-fit:

115 KB is put in 300 KB partition, leaving (185 KB, 600 KB, 350 KB, 200 KB, 750 KB, 125 KB)

500 KB is put in 600 KB partition, leaving (185 KB, 100 KB, 350 KB, 200 KB, 750 KB, 125 KB)

358 KB is put in 750 KB partition, leaving (185 KB, 100 KB, 350 KB, 200 KB, 392 KB, 125 KB)

200 KB is put in 350 KB partition, leaving (185 KB, 100 KB, 150 KB, 200 KB, 392 KB, 125 KB)

375 KB is put in 392 KB partition, leaving (185 KB, 100 KB, 150 KB, 200 KB, 17KB, 125 KB)

 

  1. Best-fit
  2. Worst-fit

 

  1. Rank the algorithms in terms of how efficiently they use memory. Explain how and why you ranked them as you did.

 

  1. In a minimum of 100 words, explain the difference between internal and external fragmentation.
  2. In a minimum of 100 words, compare the memory organization schemes of contiguous memory allocation, pure segmentation, and pure paging with respect to the following issues:
  3. External fragmentation
  4. Internal fragmentation
  5. Ability to share code across processes

 

Write a 3-4 page paper in response to using a more advanced technique, such as utility theory, to help you choose a “good” solution, rather than the “best” solution, subject to the restraints on your problem.

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Solution to restraints your problem.

Write a 3-4 page paper in response to using a more advanced technique, such as utility theory, to help you choose a “good” solution, rather than the “best” solution, subject to the restraints on your problem. Your choice of analysis technique must be governed by the goals of your investigation, so that you can refute the hypothesis you are testing. Reflect on general techniques for designing empirical studies and the importance of good data-gathering to support rigorous investigation. Give 6-8 refernces