which two statements are true?

A customer’s traffic is traversing your network, which consists of Junos devices. You must configure class of
service for the traffic to meet a service-level agreement.
In this scenario, which two statements are true? (Choose two.)

A.
By default, a packet’s loss priority can be either low or high.

B.
A packet’s loss priority can be set using classifiers or rewrite markers.

C.
By default, a packet’s loss priority can be either low, medium-low, medium-high, or high.

D.
A packet’s loss priority can be set using classifiers or policers.

Explanation:
A: Loss priority settings help determine which packets are dropped from the network during periods of
congestion. The software supports multiple packet loss priority (PLP) designations: low and high. (In addition,
medium-low and medium-high PLPs are supported when you configure tricolor marking.)
D: Packet loss priorities (PLPs) allow you to set the priority for dropping packets. You can use the PLP setting
to identify packets that have experienced congestion. Typically, you mark packets exceeding some service
level with a high loss priority—that is, a greater likelihood of being dropped. You set PLP by configuring a
classifier or a policer.

http://www.juniper.net/techpubs/en_US/junos15.1/topics/usage-guidelines/cos-setting-packet-loss-priority.html
http://www.juniper.net/documentation/en_US/junos15.1×49/topics/concept/cos-packet-loss-priorityunderstanding-security.html