Take the quiz (either here or use the PTP software) if you want to use the score to help you decide how much time to spend on this chapter. Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes,” found at the end of the book, includes both the answers and explanations. You can also find answers in the PTP testing software.
Table 13-1 ”Do I Know This Already?” Foundation Topics Section-to-Question Mapping Caution The goal of self-assessment is to gauge your mastery of the topics in this chapter. If you do not know the answer to a question or are only partially sure of the answer, you should mark that question as wrong for purposes of the self-assessment.
Giving yourself credit for an answer you incorrectly guess skews your self-assessment results and might provide you with a false sense of security.
1. What kinds of servers or services are often components of a web service?
a. Front-end or web server, back-end server
b. Front-end or web server, back-end server, database service
c. Back-end server, database service
d. Web application firewall, front-end server, database service
2. Why must DC fabrics have very low latency and jitter?
a. Responding to a single user request may require traffic to pass through the network multiple times.
b. Faster networks are less expensive to design, manage, and maintain.
c. Typical web services have too many user requests to handle if the network is too slow.
d. Low latency and jitter networks require less power .
3. What does an Internet exchange provider use a route serverfor?
a. To carry routes between transit providers
b. To carry routes between content providers
c. To carry routes between cloud providers
d. To carry routes between all the operators connected to the IXP fabric
4. What four things differentiate a network from a fabric?
a. Fabrics are regular, fabrics are planar, fabrics rely on high-bandwidth links, and fabrics have predictable performance.
b. Fabrics are not regular, fabrics are planar, fabrics rely on high fan-outs, and fabrics have predictable performance.
c. Fabrics are regular, fabrics are nonplanar, fabrics rely on high-bandwidth links, and fabrics have unpredictable performance.
d. Fabrics are regular, fabrics are nonplanar, fabrics rely on high fan-outs, and fabrics have predictable performance.
5. Why is a spine-and-leaf fabric called a spine-and-leaf fabric?
a. Because they have three stages
b. Because these fabrics have spines and leaves
c. Because they look like spiny fish
d. Because they have two layers
6. Why is a three-stage spine-and-leaf fabric called a Clos fabric?
a. After the inventor’s name, Charlie Clos
b. CLOS is an abbreviation for Combined Low-delay Open Speed
c. After the name of the research lab in which it was invented
d. Because the inventor’s wife was named Clorice
7. Are spine-and-leaf fabrics used for computer networks nonblocking or noncontending, and why?
a. Nonblocking, because every host connected to the fabric can send traffic to any other host connected to the fabric at full speed
b. Nonblocking, because the network will prevent traffic from entering the network when all the links are too full
c. Noncontending, because the network does not prevent traffic from entering the network
d. Noncontending, because no two connected workloads ever share the same bandwidth
8. Why might a network designer choose a butterfly over Clos fabric design? (Choose two.)
a. Larger scale
b. Easier to cable and build
c. Lifecycle management
d. More power efficient
9. How many ports can a butterfly fabric be designed to support?
a. Hundreds
b. Thousands
c. Hundreds of thousands
d. Millions