JNCIE Junos CoS Configuration Quiz

1. What does DSCP stand for in the context of Junos CoS?

Differentiated Services Code Point

Data Service Classification Protocol

Dynamic Service Control Point

Distributed System Code Priority

2. What is the relationship between 'behavior aggregate' (BA) classifiers and 'multifield' (MF) classifiers in Junos?

BA uses single fields; MF uses multiple fields for classification

Both are identical in function and purpose

MF is deprecated and BA is the only current method

BA is used only for internal traffic; MF for external

3. In Junos CoS, what does 'rewrite' accomplish?

Modifies the source IP address

Changes the forwarding class of a packet

Marks outgoing packets with appropriate QoS values

Encrypts packet headers

4. Which Junos configuration hierarchy level contains forwarding class definitions?

[edit interfaces]

[edit class-of-service]

[edit routing-options]

[edit security]

5. What is 'ingress classification' in Junos CoS?

Classifying traffic as it exits the device

Classifying traffic as it enters the device

Classifying internal routing traffic

Classifying traffic based on destination only

6. In Junos, at which layer of the device hierarchy is CoS typically configured?

At the routing instance level only

At the interface level and in the forwarding plane

Only in the control plane

At the physical port level exclusively

7. What does a 'drop profile' define in Junos CoS?

Which forwarding classes to disable

How many packets to drop per second

The probability of dropping packets based on queue depth

The source IP addresses to block

8. Which scheduling algorithm is commonly used in Junos to ensure fair bandwidth distribution?

First In First Out (FIFO)

Weighted Round Robin (WRR)

Last In First Out (LIFO)

Random Early Detection (RED)

9. In Junos, what is a 'queue' in the context of CoS?

A temporary storage area for packets awaiting transmission

A routing table entry

A security filter list

A bandwidth reservation protocol

10. How many bits does DSCP use for marking traffic in the IP header?

2 bits

4 bits

6 bits

8 bits

11. What is the primary purpose of Class of Service (CoS) in Juniper Junos?

To encrypt all traffic on the network

To classify, mark, and prioritize traffic based on business requirements

To increase bandwidth for all users equally

To block unauthorized traffic at the firewall

12. In Junos, which field is commonly used to classify traffic at Layer 3?

MAC address

DSCP or IP precedence

VLAN tag only

Source port number

13. What is the purpose of a traffic classifier in Junos CoS?

To mark packets with QoS values

To identify and assign traffic to forwarding classes

To drop excess packets

To encrypt sensitive traffic

14. Which Junos component determines the order in which packets are transmitted from an interface?

Classifier

Policer

Scheduler

Marker

15. In Junos CoS, what action can a policer take on traffic that exceeds the configured rate?

Encrypt it

Forward it immediately

Discard it or mark it with a different code point

Duplicate it

16. What does a policer do in a Junos CoS configuration?

Encrypts traffic based on source IP

Limits traffic rate and takes action on excess traffic

Compresses all outgoing packets

Duplicates traffic for redundancy

17. Which of the following is NOT a standard forwarding class in Junos?

Best Effort

Assured Forwarding

Expedited Forwarding

Premium Priority

18. What is the maximum number of forwarding classes supported on most Juniper platforms?

4

8

16

32

19. In Junos, what does the term 'forwarding class' represent?

A physical network interface

A logical grouping of traffic with similar QoS requirements

A routing protocol configuration

A security zone definition

20. Which Junos component is responsible for mapping incoming traffic to forwarding classes?