Class OF Service

Which standard Junos forwarding class is reserved for control plane traffic such as routing protocols and management traffic?

You are troubleshooting a scenario where multi-field classifiers and behavior aggregate classifiers are both configured on the same ingress interface. In what order does Junos process classification?

You are deploying a Junos EX Series switch in a campus network. Voice packets arrive untagged from IP phones on access ports, while a trunk uplink carries traffic already marked with DSCP values from the core. You need to ensure that all ingress traffic on the uplink is classified into forwarding classes based solely on the existing DSCP bits without inspecting Layer 3 or Layer 4 headers. Which classifier type should you apply to the uplink interface?

You need to configure a classifier that inspects the Multiprotocol Label Switching (MPLS) experimental (EXP) bits. Which classifier type must you specify?

In Junos CoS architecture, what role does a forwarding class play?

When applying a rewrite rule on an interface, you notice that packets are being remarked incorrectly. You realize that both a DSCP rewrite rule and an IEEE 802.1p rewrite rule are configured on the same physical interface. What is the rule regarding multiple rewrite rules on a single interface in Junos?

Which statement describes the function of a drop-profile in Junos CoS?

You are configuring a Junos router where a customer wants assured forwarding for three classes of traffic: AF11, AF21, and AF31. Each class must receive its own bandwidth guarantee and its own congestion behaviour. You are defining the behavior aggregate classifier. Which configuration element maps the incoming DSCP values to the correct forwarding classes and loss priorities?

When configuring a hierarchical scheduler map on an MX Series router, what is the primary purpose of the aggregate level shaping?

You are troubleshooting a CoS issue on a Juniper EX Series switch. You have configured a policer to limit traffic to 100 Mbps with a burst size of 10 KB. You notice that traffic occasionally exceeds 100 Mbps for short periods but is not being dropped. Which statement explains this behavior?

An engineer configures a two-color policer on an MX router. What are the two states or outcomes for evaluated packets in a standard two-color policer?

Which TWO parameters can be configured within a Junos scheduler definition? (Choose two)

You are configuring Class of Service on an MX Series router. You want to ensure that the best-effort forwarding class receives at least 10 Mbps of bandwidth during congestion on a 1 Gbps interface, but you also want to allow it to use additional bandwidth if other queues are idle. Which scheduler configuration should you apply?

An administrator configures a scheduler map on a Junos MX Series router with three queues: best-effort with transmit-rate remainder, expedited-forwarding with a strict-high transmit rate, and assured-forwarding with a transmit rate of 30 percent. Users report that voice quality degrades whenever assured-forwarding traffic bursts, even though expedited-forwarding is marked strict-high. Which statement explains this behavior?

An administrator applies a DSCP rewrite rule to an SRX Series device interface that faces an untrusted WAN. The goal is to mark voice packets with EF (46) and best-effort traffic with 0 before they leave the device. After applying the rewrite rule, the administrator notices that some packets still leave with their original DSCP values. Which statement explains the most likely cause?

Which TWO statements describe the characteristics of Random Early Detection (RED) and drop profiles in Junos? (Choose two)

A network engineer notices that on a Junos EX Series switch, the voice queue is configured with strict-high priority, but during periods of congestion, data traffic is being dropped while voice traffic is unaffected. The engineer wants to ensure that voice traffic is not only prioritized but also limited so it cannot consume all interface bandwidth. Which scheduler property should be added to the voice queue to cap its maximum transmission rate?

Which THREE types of classifiers are natively supported in Junos Class of Service? (Choose three)

You are configuring a Junos SRX Series device to protect the control plane from a flood of BGP keepalives. You want to police traffic destined to the Routing Engine and apply a rate limit that drops excess packets while allowing normal protocol operation. Which CoS mechanism should you use?

You are tuning an egress interface on a Junos device for a service provider environment. You have configured three drop profiles and applied them to a scheduler map. You need to verify that the weighted random early detection (WRED) behaviour is operating as intended under congestion. Which TWO statements correctly describe how Junos implements drop profiles and WRED? (Choose two.)

What is the primary function of a behavior aggregate (BA) classifier in Junos CoS?

Which TWO statements are correct regarding the behavior of policers in Junos? (Choose two)

You want to map three loss priorities (low, medium-low, high) to different drop profiles within a specific forwarding class. Which statement should you use inside the scheduler configuration?

An enterprise WAN edge router running Junos OS has a single 1 Gbps uplink. The design requires that when total egress congestion occurs, the queue carrying business-critical database replication traffic must be guaranteed a minimum of 400 Mbps, while the queue carrying guest internet traffic must never consume more than 200 Mbps even if bandwidth is idle. Which CoS configuration accomplishes this requirement?

Which configuration stanza is used to define custom forwarding classes in Junos?

A network engineer is configuring class of service on a Junos switch and wants to guarantee that the network control traffic forwarding class always has bandwidth available for routing protocol updates, even during heavy data congestion. The engineer also wants to ensure that this class is not starved by other queues. Which scheduler configuration should the engineer apply to the network control forwarding class?

Which THREE methods are valid for marking packet headers using CoS rewrite rules in Junos? (Choose three)

Which command displays the configured scheduler maps and their association with forwarding classes on a Junos device?

A network administrator is configuring CoS on a Junos EX Series switch and wants to verify the mapping between forwarding classes and queues as currently applied to a specific interface. Which operational command should the administrator use to display the forwarding class to queue mapping along with scheduler and classifier details for a given interface?

Which TWO statements are true regarding traffic shapers versus policers in Junos? (Choose two)

Which command is used to verify the operational state of forwarding classes and their assigned queues on a specific interface on Junos?

You are configuring a rewrite rule on a Junos device to mark outgoing packets with the appropriate DSCP value based on their forwarding class. You want to ensure that packets in the expedited-forwarding class are marked with DSCP EF (46). Which configuration correctly accomplishes this?

Which THREE actions can be executed by a firewall filter policer when traffic exceeds the specified rate? (Choose three)

You need to ensure that delay-sensitive voice traffic is serviced before all other queues on an egress interface. Which scheduler property should you configure for the voice forwarding class?

You are troubleshooting a Junos EX Series switch where a firewall filter applied to an ingress interface uses a policer to mark excess traffic as loss priority high. Downstream, a scheduler map on the egress interface is supposed to drop those high-loss-priority packets first using a drop profile. However, all excess packets are being dropped immediately at ingress instead of being forwarded and selectively discarded at egress. What is the most likely cause?

You are deploying a Junos EX Series switch in a campus network. Voice traffic arrives untagged and must be placed into the expedited-forwarding forwarding class based solely on the Differentiated Services Code Point (DSCP) value carried in the IP header. No firewall filter is allowed on the ingress interface. Which classifier type should you apply to the interface?

You have configured a custom scheduler map, but traffic in the best-effort queue is being starved during periods of heavy congestion. Which scheduler parameter should you adjust to guarantee a minimum bandwidth for this queue?

You are deploying a Junos device where a single physical interface carries both a latency-sensitive multicast video stream and best-effort file transfers. You must ensure that the video traffic is transmitted with the lowest possible per-hop latency and jitter, even when the best-effort queue is congested, without starving the other queues. Which CoS feature should you configure on the egress interface to meet this requirement?

You want to apply a rewrite rule on an outgoing interface to remark the DSCP bits of packets leaving your Juniper router. Where must this rewrite rule be applied within the CoS hierarchy?