13. Which statement describes a network that supports QoS?
- The fewest possible devices are affected by a failure.
- The network should be able to expand to keep up with user demand.
- The network provides predictable levels of service to different types of traffic.
- Data sent over the network is not altered in transmission.
14. Which QoS model is very resource intensive and provides the highest guarantee of QoS?
- soft QoS
15. Which DSCP value should be applied to voice traffic?
16. What happens when the memory queue of a device fills up and new network traffic is received?
- The network device sends the received traffic immediately.
- The network device will drop the arriving packets.
- The network device drops all traffic in the queue.
- The network device queues the received traffic while sending previously received trac.
17. In network design, which technology can be implemented to prioritize traffic based on its importance and technical requirements?
18. What functionality is required on routers to provide remote workers with VoIP and videoconferencing capabilities?
19. What are the three categories of tools that can be used in IP networks to implement QoS? (Choose three.)
- classification and marking
- congestion management
- congestion avoidance
- integrated services
- differentiated services
- best effort
20. When using the IP phones, users complain that sound quality is poor and sometimes the voice heard is broken. Which section of the router configuration should the network administrator check in order to find the possible cause?
- access control lists
- interface bandwidth
- traffic queuing parameters
- routing protocol update settings
21. What type of queuing provides the best quality for voice applications?
- custom queuing
- FIFO queuing
- priority queuing
- weighted round robin (WRR) queuing
22. What role do network devices play in the IntServ QoS model?
- Network devices ensure that resources are available before traffic is allowed to be sent by a host through the network.
- Network devices provide a best-effort approach to forwarding traffic.
- Network devices are configured to service multiple classes of traffic and handle traffic as it may arrive.
- Network devices use QoS on a hop-by-hop basis to provide excellent scalability.
23. Which QoS model uses the DSCP bits to mark packets and provides 64 possible classes of service?
24. Which two statements are true about WRED? (Choose two.)
- WRED will use the average queue depth of an interface when determining if a packet should be dropped.
- WRED uses the IP precedence or DSCP marking of a packet when determining if a packet should be dropped.
- WRED does not support ECN.
- WRED uses a tail drop system for its queue buffers.
- WRED will drop packets marked AFx1 more aggressively than it will drop packets marked AFx3 from the queue.
“Do I Know This Already?” Quiz Answers:
1. Which of the following are the leading causes of quality of service issues? (Choose all that apply.)
- Bad hardware
- Lack of bandwidth
- Latency and jitter
- Copper cables
- Packet loss
2. Network latency can be broken down into which of the following types? (Choose all that apply.)
- Propagation delay (fixed)
- Time delay (variable)
- Serialization delay (fixed)
- Processing delay (fixed)
- Packet delay (fixed)
- Delay variation (variable)
3. Which of the following is not a QoS implementation model?
- Expedited forwarding
- Best effort
4. Which of the following is the QoS implementation model that requires a signaling protocol?
- Best Effort
5. Which of the following is the most popular QoS implementation model?
- Best effort
6. True or false: Traffic classification should always be performed in the core of the network.
7. The 16-bit TCI field is composed of which fields? (Choose three.)
- Priority Code Point (PCP)
- Canonical Format Identifier (CFI)
- User Priority (PRI)
- Drop Eligible Indicator (DEI)
- VLAN Identifier (VLAN ID)
8. True or false: The DiffServ field is an 8-bit Differentiated Services Code Point (DSCP) field that allows for classification of up to 64 values (0 to 63).
9. Which of the following is not a QoS PHB?
- Best Effort (BE)
- Class Selector (CS)
- Default Forwarding (DF)
- Assured Forwarding (AF)
- Expedited Forwarding (EF)
10. Which traffic conditioning tool can be used to drop or mark down traffic that goes beyond a desired traffic rate?
- None of the above
11. What does Tc stand for? (Choose two.)
- Committed time interval
- Token credits
- Bc bucket token count
- Traffic control
12. Which of the following are the recommended congestion management mechanisms for modern rich-media networks? (Choose two.)
- Class-based weighted fair queuing (CBWFQ)
- Priority queuing (PQ)
- Weighted RED (WRED)
- Low-latency queuing (LLQ)
13. Which of the following is a recommended congestion-avoidance mechanism for modern rich-media networks?
- Weighted RED (WRED)
- Tail drop