Reference no: EM132411311

Assignment - Network Layer

Review questions -

1. Briefly describe routing - the primary function of the network layer.

2. How are IP addresses similar to MAC addresses? In what ways are the two addresses different?

3. What is the need for a computer address at the IP layer when computers also have a MAC address?

4. What are the advantages of designing the Internet in such a way that specialized devices called routers handle all the details of routing? What may be the possible disadvantages?

5. What are the advantages of designing IP as a best-effort protocol?

6. What are RFCs? Read RFC 791 that defines IP, and briefly describe one thing in the RFC that caught your attention? (This is not a trick question, just a way for you to express what you personally found interesting).

7. Which, in your opinion, are the three most important fields in the IP header? Briefly describe the functions of these fields.

8. What is the need for the time-to-live field in the IP header?

9. What is the size of the largest possible IP packet?

10. How many objects can be uniquely labeled with 10-bit address labels?

11. You wish to assign unique labels to 200 objects using binary numbers. What is the minimum number of bits needed?

12. How would you represent 217 in binary? 168?

13. What decimal number does the binary number 10001101 represent? 11011001?

14. What is dotted decimal notation?

15. What information is conveyed by each part of a two-part IP address?

16. How are the 32 bits of an IP address organized in a typical large network?

17. Find the IP addresses of any five department websites at your school. Do you observe any patterns in the IP addresses of the websites? (You can find the IP addresses for URLs in many ways. Many websites will give you the IP address if you provide a URL. Alternately, you can open a command prompt or terminal window and type in nslookup <URL>).

18. In what way are the 32 bits of an IP address organized similarly to the 10 digits of phone numbers? In what way are they different?

19. What were the three address classes in early IP networks? How many hosts (computers) could be accommodated in a network in each address class?

20. What are the disadvantages of using address classes? How does CIDR overcome these disadvantages?

21. What is registry in the context of IP addresses?

22. What requirements must an organization satisfy in order to obtain IP addresses directly from a registry?

23. What is the correct representation of the IPv6 address, as specified by RFC 5952 - 2607:FE50:0010:0000:0000:1000:0101:abcd?

24. On your home computer, what is the IP address reported by ipconfig /all (Windows) or ifconfig (MAC/ Linux)?

25. From your home computer, go to www.whatismyip.com and make a note of your IP address. Type this address into the search box at www.arin.net. Who is the owner of that address block?

Hands-on exercise -

ipconfig

1. What are the IP addresses assigned to the interfaces on your computer?

2. We have seen in this chapter that the network parts of IP addresses identify the owners of IP address blocks. Use the WHOIS search facility at the American Registry for Internet numbers to search the WHOIS database and identify the owner of the address block to which your IP address belongs. You can do this by visiting arin → typing in your IP address into the search WHOIS field on the site → press enter or click the button next to the search field. Follow the link to the "related organization's POC records" just below the table to gather information on the following fields associated with your IP address:

a. OrgName

b. NetRange

c. NetType

d. NameServer

e. OrgTechName

f. OrgTechPhone

3. Is the OrgName the same as your ISP's name? (If not, we will explore the main reason for this in Chapter 7).

ping

1. How does ping work? Use Wikipedia or other resource to write a brief description of how ping works.

2. Use Wikipedia or other resource to write a brief description of the Internet Control Message Protocol (ICMP) and its use.

3. Ping the website of your university. Show the output. What is the average round-trip time? (If your university is locked down, i.e. does not respond to ping queries, try your ISP's web site)

4. Ping the website of a university in a neighboring city or town. Show the output. What is the average round-trip time? (Again, if the website is locked down, try the website of a company in another state)

5. Ping the website of a company located abroad. Show the output. What is the average round-trip time?

6. You wake up one day to find that you are unable to connect to the Internet from home. You make some calls to your friends and neighbors and find that they have no issues connecting to the Internet. You conclude that the fault is within your home. As shown, there are two networking components within your home-your computer and your home router. As shown, the IP address of the home router is the IP address of the default gateway in your ipconfig output, and home routers typically respond to ping requests. How can you use ping to determine whether the network connectivity problem is at the home router or at your computer?

7. The creator of ping has an interesting description of its creation. What is the most interesting story narrated by the author of the use of ping for network trouble-shooting?

8. (optional) A related utility is pathping. It combines the features of ping (reachability), tracert (hop visibiility) and packet loss statistics per hop. The most useful information in the output is the packet loss information.

Critical thinking questions -

1. The genetic code uses three-letter DNA-words, where each letter can take four values - A, C, G, and T. How many words are possible in the DNA dictionary?

IT infrastructure design exercise -

1. If each computer on TrendyWidgets's network is allocated an IP address, how many IP addresses is TrendyWidgets likely to need?

2. Based on this estimate, what is a CIDR address-block size suitable for TrendyWidgets?

Example case questions -

1. Based on the case, what computer networking technologies do retailers like Wal-Mart use?

2. Based on the case, how do retailers like Wal-Mart use computer networks to lower the costs of goods sold?

3. What is cross-docking?

4. Among the processes at a retailer that can be managed using IT are merchandise planning, sourcing, distribution, and store operations. Briefly define each process using any information source available to you (such as Wikipedia or Google).

5. For each of these processes, give an example of how IT can be used to manage the process. If your example uses computer networks, highlight the role of the network.

6. Based on the case, what are some reasons that Kmart did not achieve the same benefits from IT investments as Wal-Mart?