You need to ensure that your high-priority traffic uses the best-possible route while your best-effort traffic uses a
lower preference route. You want to use CoS-based forwarding to use the DSCP values of the different types of
traffic to assign the LSP that should be used for the next hop.
Which three additions must be made to the configuration to satisfy the requirement? (Choose three.)

A.
a class-of-service forwarding policy

B.
a policy statement for LSP next-hop selection

C.
an important policy applied to the forwarding table

D.
an export policy applied to the forwarding table

E.
a multifield firewall filter for LSP next-hop selection

Explanation:
D: The final step is to apply the route filter to routes exported to the forwarding engine. This is shown in the
following example:
routing-options {
forwarding-table {
export my-cos-forwarding;
}
}
This configuration instructs the routing process to insert routes to the forwarding engine matching my-cosforwarding with the associated next-hop CBF rules.
A: Assigning Forwarding Class and DSCP Value for Routing Engine-Generated Traffic You can set the
forwarding class and differentiated service code point (DSCP) value for traffic originating in the Routing Engine.
To configure forwarding class and DSCP values that apply to Routing Engine–generated traffic only, apply an
output filter to the loopback (lo.0) interface and set the appropriate forwarding class and DSCP bit configuration
for various protocols.
E: The following example assigns Routing Engine sourced ping packets (using ICMP) a DSCP value of 38 and
a forwarding class of af17, OSPF packets a DSCP value of 12 and a forwarding class of af11, and BGP
packets (using TCP ) a DSCP value of 10 and a forwarding class of af16.
[edit class-of-service]
forwarding-classes {
class af11 queue-num 7;
class af12 queue-num 1;
class af13 queue-num 2;
class af14 queue-num 4;
class af15 queue-num 5;
class af16 queue-num 4;
class af17 queue-num 6;
class af18 queue-num 7;
}
[edit firewall filter family inet]
filter loopback-filter {
term t1 {
from {
protocol icmp; # For pings
}
then {
forwarding-class af17;
dscp 38;
}
}
term t2 {
from {
protocol ospf; # For OSPF
}
then {
forwarding-class af11;
dscp 12;
}
}
}
Etc.
https://www.juniper.net/techpubs/en_US/junos16.1/topics/usage-guidelines/cos-assigning-fc-dscpto-re-pkts.html
http://www.juniper.net/techpubs/en_US/junos13.3/information-products/pathway-pages/cos/forwardingclasses.pdf (page 42)