Chp. 10 Chapter Questions

Question 1

What is the basic structure of the Internet?

Answer 1

• The Internet is hierarchical in structure.
• At the top are the very large national Internet service providers like AT&T, Sprint, etc. with regional and local internet service providers reporting up through this hierarchy.

Question 2

Explain how the Internet is a network of networks.

Answer 2

• The Internet was originally run by the U.S. National Science Foundation (NSF), but now the NAP’s are commercial enterprises run by various common carriers.
• These NAP’s are connected to other NAP’s, who have several ISPs attached, who have regional ISPs attached to them, who have consumers attached to them.
• This spider web branches out into countless networks all over the world. T

Question 3

What is an IXP?

Answer 3

• Internet Exchange Points are connection points between Internet Service Providers.

Question 4

What is a POP?

Answer 4

• A POP is an acronym for “point of presence.”
• The POP is the place at which the ISP providers services to its customers.

Question 5

Explain one reason why you might experience long response times in getting a Web page from a server in your own city.

Answer 5

If the other organization uses a different local ISP, which in turn uses a different regional ISP, the message may have to travel all the way to the Chicago IXP before it can move between the two separate parts of the Internet.

Question 6

What type of circuits are commonly used to build the Internet today? What type of circuits are commonly used to build Internet 2?

Answer 6

1. Today, the backbone circuits of the major U.S. national ISPs operate at SONET OC-192

(10 Gbps).

2. Internet 2 will consist of circuits at least at OC-192 levels, with OC-768 (80 Gbps) and possibly even OC-3072 (160 Gbps) available.

Question 7

Compare and contrast cable modem and DSL.

Answer 7

• One of the main differences between the two is that DSL customers have a direct connection back to the end office with point-to-point technology, whereas cable modems use shared multipoint circuits.

Question 8

Explain how DSL works.

Answer 8

• DSL requires equipment that is installed at the end of the cable (within the house or office) which allows traditional telephone service (POTS) to take advantage of much higher data transmissions rates via the existing cable in the local loop.

Question 9

How does a DSL modem differ from a DSLAM?

Answer 9

• A DSL modem produces Ethernet 10Base-T packets
• The DSLAM produces ATM data

Question 10

Explain how ADSL works.

Answer 10

• ADSL is the most common type of DSL used today.
• It uses frequency division multiplexing to create three separate channels over the one local loop circuit.

Question 11

Explain how a cable modem works

Answer 11

• DSL is a point-to-point technology, whereas cable modems use shared multipoint circuits.
• Cable modems must compete with other users for the available capacity thus they are slower.

Question 12

What is an OE converter? A CMTS?

Answer 12

1. An OE is an optical-electrical converter, which converts between the coaxial cable on the customer side and fiber-optic cable on the cable TV company side.
2. The CMTS contains a series of cable modems/multiplexers and converts the data from cable modem protocols into protocols needed for Internet traffic

Question 13

Which is better, cable modem or DSL? Explain.

Answer 13

• Depends on local service provider

Question 14

Explain how FTTH works

Answer 14

• FTTH is a dedicated point‐to‐point service like DSL, not a shared multipoint service like cable modem.
• one fiber‐optic cable that is run past each house or office in the neighborhood.

Question 15

What are some future technologies that might change how we access the Internet?

Answer 15

• Passive Optical Networking
• Internet 2.

Question 16

Explain how WiMax works.

Answer 16

• Mobile WiMax works in much the same way as Wi‐Fi.
• The laptop or smart phone has a WIMAX network interface card (NIC) and uses it to establish a connection to a WiMax access point (AP).

Question 17

What are the principal organizations responsible for Internet governance, and what do they do?

Answer 17

• There is no one organization that operates the Internet.
• The closest thing the Internet has to an owner is the Internet Society (ISOC).
• The ISOC mission is to ensure “the open development, evolution and use of the Internet for the benefit of all people.

Question 18

How is the IETF related to the IRFT?

Answer 18

• The ISOC comprises of four bodies that act together to govern, IETF and IRFT are two of the four.

Question 19

What is the principal American organization working on the future of the Internet?

Answer 19

• The Internet Society
• It works in three general areas: public policy, education, and standards.

Question 20

What is Internet2®?

Answer 20

• primary focus to develop advanced networking as well as other innovative technologies for research and education

Question 21

What is a gigapop?

Answer 21

• These are new points-of-presence (POP) that work at gigabit speeds.

Question 22

Today, there is no clear winner in the competition for higher-speed Internet access. What technology or technologies do you think will dominate in 2 years’ time? Why?

Answer 22

1. There is no answer for this, as technology changes day by day
2. however, I think Internet 2 development is definitely something to watch.

Question 23

Would you be interested in subscribing to 100 Mbps FTTH for a monthly price of $100? Why or why not?

Answer 23

• This answer depends on the options that you currently have and the amount of uploading and downloading you actually perform.
• Many locations offer DSL and/or cable access for $30 per month with data rates up to 15 Mbps.
• Obviously increasing the download rate to 100 Mbps would provide a much faster connection, but at more than double the price.

Question 24

Many experts predicted that small, local ISPs would disappear as regional and national ISPs began offering local access. This hasn’t happened. Why?

Answer 24

• There have been some consolidation recently, but with all the change underway, what would the larger companies really be purchasing.