Juniper JN0-664 Exam Dumps [2023] Practice Valid Exam Dumps Question [Q21-Q39]

NO.21 Which three mechanisms are used by Junos platforms to evaluate incoming traffic for CoS purposes? (Choose three )

rewrite rules

behavior aggregate classifiers

traffic shapers

fixed classifiers

multifield classifiers

NO.22 Exhibit
user@Rl show configuration interpolated-profile { interpolate {
fill-level [ 50 75 drop-probability [ > }
class-of-service drop-profiles
];
20 60 ];
Which two statements are correct about the class-of-service configuration shown in the exhibit? (Choose two.)

The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full.

The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to
75% full

To use this drop profile, you reference it in a scheduler.

To use this drop profile, you apply it directly to an interface.

Explanation
class-of-service (CoS) is a feature that allows you to prioritize and manage network traffic based on various criteria, such as application type, user group, or packet loss priority. CoS uses different components to classify, mark, queue, schedule, shape, and drop traffic according to the configured policies.
One of the components of CoS is drop profiles, which define how packets are dropped when a queue is congested. Drop profiles use random early detection (RED) algorithm to drop packets randomly before the queue is full, which helps to avoid global synchronization and improve network performance. Drop profiles can be discrete or interpolated. A discrete drop profile maps a specific fill level of a queue to a specific drop probability. An interpolated drop profile maps a range of fill levels of a queue to a range of drop probabilities and interpolates the values in between.
In the exhibit, we can see that the class-of-service configuration shows an interpolated drop profile with two fill levels (50 and 75) and two drop probabilities (20 and 60). Based on this configuration, we can infer the following statements:
* The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full. This is not correct because the drop profile is interpolated, not discrete. This means that the drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full. The drop probability for any fill level between 50% and 75% can be calculated by using linear interpolation formula.
* The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to
75% full. This is correct because the drop profile is interpolated and uses linear interpolation formula to calculate the drop probability for any fill level between 50% and 75%. For example, if the fill level is
60%, the drop probability is 28%, which is calculated by using the formula: (60 – 50) / (75 – 50) * (60 –
20) + 20 = 28.
* To use this drop profile, you reference it in a scheduler. This is correct because a scheduler is a component of CoS that determines how packets are dequeued from different queues and transmitted on an interface. A scheduler can reference a drop profile by using the random-detect statement under the
[edit class-of-service schedulers] hierarchy level. For example: scheduler test { transmit-rate percent 10; buffer-size percent 10; random-detect test-profile; }
* To use this drop profile, you apply it directly to an interface. This is not correct because a drop profile cannot be applied directly to an interface. A drop profile can only be referenced by a scheduler, which can be applied to an interface by using the scheduler-map statement under the [edit class-of-service interfaces] hierarchy level. For example: interfaces ge-0/0/0 { unit 0 { scheduler-map test-map; } }

NO.23 You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. In this scenario, which statement is correct?

You must assign a unique site number to each attached site’s configuration.

This type of VPN only supports Ethernet interfaces when connecting to CE devices.

This type of VPN requires the support of the inet-vpn NLRI on all core BGP devices

You must use the same route-distinguiaher value on both PE devices.

NO.24 You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. Your PE-2 device connects to two sites within the s VPN In this scenario, which statement is correct?

By default on PE-2, the site’s local ID is automatically assigned a value of 0 and must be configured to match the total number of attached sites.

You must create a unique Layer 2 VPN routing instance for each site on the PE-2 device.

You must use separate physical interfaces to connect PE-2 to each site.

By default on PE-2, the remote site IDs are automatically assigned based on the order that you add the interfaces to the site configuration.

NO.25 Exhibit

Referring to the exhibit, PIM-SM is configured on all routers, and Anycast-RP with Anycast-PIM is used for the discovery mechanism on RP1 and RP2. The interface metric values are shown for the OSPF area.
In this scenario, which two statements are correct about which RP is used? (Choose two.)

Source2 will use RP2 and Received will use RP2 for group 224.2.2.2.

Source2 will use RP1 and Receiver2 will use RP1 for group 224.2.2.2.

Source1 will use RP1 and Receiver1 will use RP1 for group 224.1.1.1.

Source1 will use RP1 and Receiver1 will use RP2 for group 224.1 1 1

NO.26 When building an interprovider VPN, you notice on the PE router that you have hidden routes which are received from your BGP peer with family inet labeled-unica3t configured.
Which parameter must you configure to solve this problem?

Under the family inet labeled-unicast hierarchy, add the explicit null parameter.

Under the protocols ospf hierarchy, add the traffic-engineering parameter.

Under the family inet labeled-unicast hierarchy, add the resolve-vpn parameter.

Under the protocols mpls hierarchy, add the traffic-engineering parameter

NO.27 What is the correct order of packet flow through configurable components in the Junos OS CoS features?

Multifield Classifier -> Behavior Aggregate Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Rewrite Marker -> Scheduler/Shaper/RED

Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker

Behavior Aggregate Classifier -> Input Policer -> Multifield Classifier -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker

Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Scheduler/Shaper/RED -> Output Policer -> Rewrite Marker

NO.28 Exhibit

Referring to the exhibit, you are receiving the 192.168 0 0/16 route on both R3 and R4 from your EBGP neighbor You must ensure that R1 and R2 receive both BGP routes from the route reflector In this scenario, which BGP feature should you configure to accomplish this behavior?

add-path

multihop

multipath

route-target

NO.29 Exhibit

You are running a service provider network and must transport a customer’s IPv6 traffic across your IPv4-based MPLS network using BGP You have already configured mpis ipv6-tunneling on your PE routers.
Which two statements are correct about the BGP configuration in this scenario? (Choose two.)

You must configure family inet6 labcled-unicast between PE routers.

You must configure family inet6 unicaat between PE and CE routers.

You must configure family inet6 add-path between PE and CE routers.

You must configure family inet6 unicast between PE routers

NO.30 Exhibit

Click the Exhibit button-Referring to the exhibit, which two statements are correct about BGP routes on R3 that are learned from the ISP-A neighbor? (Choose two.)

By default, the next-hop value for these routes is not changed by ISP-A before being sent to R3.

The BGP local-preference value that is used by ISP-A is not advertised to R3.

All BGP attribute values must be removed before receiving the routes.

The next-hop value for these routes is changed by ISP-A before being sent to R3.

Explanation
BGP is an exterior gateway protocol that uses path vector routing to exchange routing information among autonomous systems. BGP uses various attributes to select the best path to each destination and to propagate routing policies. Some of the common BGP attributes are AS path, next hop, local preference, MED, origin, weight, and community. BGP attributes can be classified into four categories: well-known mandatory, well-known discretionary, optional transitive, and optional nontransitive. Well-known mandatory attributes are attributes that must be present in every BGP update message and must be recognized by every BGP speaker.
Well-known discretionary attributes are attributes that may or may not be present in a BGP update message but must be recognized by every BGP speaker. Optional transitive attributes are attributes that may or may not be present in a BGP update message and may or may not be recognized by a BGP speaker. If an optional transitive attribute is not recognized by a BGP speaker, it is passed along to the next BGP speaker. Optional nontransitive attributes are attributes that may or may not be present in a BGP update message and may or may not be recognized by a BGP speaker. If an optional nontransitive attribute is not recognized by a BGP speaker, it is not passed along to the next BGP speaker. In this question, we have four routers (R1, R2, R3, and R4) that are connected in a full mesh topology and running IBGP. R3 receives the 192.168.0.0/16 route from its EBGP neighbor and advertises it to R1 and R4 with different BGP attribute values. We are asked which statements are correct about the BGP routes on R3 that are learned from the ISP-A neighbor. Based on the information given, we can infer that the correct statements are:
* By default, the next-hop value for these routes is not changed by ISP-A before being sent to R3. This is because the default behavior of EBGP is to preserve the next-hop attribute of the routes received from another EBGP neighbor. The next-hop attribute indicates the IP address of the router that should be used as the next hop to reach the destination network.
* The BGP local-preference value that is used by ISP-A is not advertised to R3. This is because the local-preference attribute is a well-known discretionary attribute that is used to influence the outbound traffic from an autonomous system. The local-preference attribute is only propagated within an autonomous system and is not advertised to external neighbors.
References: : https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html :
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html :
https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13759-37.html

NO.31 Exhibit

Which two statements about the output shown in the exhibit are correct? (Choose two.)

The PE is attached to a single local site.

The connection has not flapped since it was initiated.

There has been a VLAN ID mismatch.

The PE router has the capability to pop flow labels

Explanation
According to 1 and 2, BGP Layer 2 VPNs use BGP to distribute endpoint provisioning information and set up pseudowires between PE devices. BGP uses the Layer 2 VPN (L2VPN) Routing Information Base (RIB) to store endpoint provisioning information, which is updated each time any Layer 2 virtual forwarding instance (VFI) is configured. The prefix and path information is stored in the L2VPN database, which allows BGP to make decisions about the best path.
In the output shown in the exhibit, we can see some information about the L2VPN RIB and the pseudowire state. Based on this information, we can infer the following statements:
* The PE is attached to a single local site. This is correct because the output shows only one local site ID (1) under the L2VPN RIB section. A local site ID is a unique identifier for a site within a VPLS domain.
If there were multiple local sites attached to the PE, we would see multiple local site IDs with different prefixes.
* The connection has not flapped since it was initiated. This is correct because the output shows that the uptime of the pseudowire is equal to its total uptime (1w6d). This means that the pseudowire has been up for one week and six days without any interruption or flap.
* There has been a VLAN ID mismatch. This is not correct because the output shows that the remote and local VLAN IDs are both 0 under the pseudowire state section. A VLAN ID mismatch occurs when the remote and local VLAN IDs are different, which can cause traffic loss or misdelivery. If there was a VLAN ID mismatch, we would see different values for the remote and local VLAN IDs.
* The PE router has the capability to pop flow labels. This is correct because the output shows that the flow label pop bit is set under the pseudowire state section. The flow label pop bit indicates that the PE router can pop (remove) the MPLS flow label from the packet before forwarding it to the CE device.
The flow label is an optional MPLS label that can be used for load balancing or traffic engineering purposes.

NO.32 Exhibit

Referring to the exhibit, which statement is true?

The 10.101.1.0/24 route will be shared if the vrf-table-label parameter is configured.

The 10.101.1.0/24 route will only be shared if BGP is configured in the routing instance

The 10.101.1 0/24 route will be shared if there are other VRFs that use the same route target community

The 10.101.1.0/24 route will be shared if the auto-export parameter is configured

NO.33 In IS-IS, which two statements are correct about the designated intermediate system (DIS) on a multi-access network segment? (Choose two)

A router with a priority of 10 wins the DIS election over a router with a priority of 1.

A router with a priority of 1 wins the DIS election over a router with a priority of 10.

On the multi-access network, each router forms an adjacency to every other router on the segment

On the multi-access network, each router only forms an adjacency to the DIS.

NO.34 Exhibit

CE-1 must advertise ten subnets to PE-1 using BGP Once CE-1 starts advertising the subnets to PE-1, the BGP peering state changes to Active.
Referring to the CLI output shown in the exhibit, which statement is correct?

CE-1 is advertising its entire routing table.

CE-1 is configured with an incorrect peer AS

The prefix limit has been reached on PE-1

CE-1 is unreachable

NO.35 Exhibit

You want to implement the BGP Generalized TTL Security Mechanism (GTSM) on the network Which three statements are correct in this scenario? (Choose three)

You can implement BGP GTSM between R2, R3, and R4

BGP GTSM requires a firewall filter to discard packets with incorrect TTL.

You can implement BGP GTSM between R2 and R1.

BGP GTSM requires a TTL of 1 to be configured between neighbors.

BGP GTSM requires a TTL of 255 to be configured between neighbors.

Explanation
BGP GTSM is a technique that protects a BGP session by comparing the TTL value in the IP header of incoming BGP packets against a valid TTL range. If the TTL value is within the valid TTL range, the packet is accepted. If not, the packet is discarded. The valid TTL range is from 255 – the configured hop count + 1 to
255. When GTSM is configured, the BGP packets sent by the device have a TTL of 255. GTSM provides best protection for directly connected EBGP sessions, but not for multihop EBGP or IBGP sessions because the TTL of packets might be modified by intermediate devices.
In the exhibit, we can see that R2, R3, and R4 are in the same AS (AS 20) and R1 is in a different AS (AS 10).
Based on this information, we can infer the following statements:
* You can implement BGP GTSM between R2, R3, and R4. This is not correct because R2, R3, and R4 are IBGP peers and GTSM does not provide effective protection for IBGP sessions. The TTL of packets between IBGP peers might be changed by intermediate devices or routing protocols.
* BGP GTSM requires a firewall filter to discard packets with incorrect TTL. This is not correct because BGP GTSM does not require a firewall filter to discard packets with incorrect TTL. BGP GTSM uses TCP option 19 to negotiate GTSM capability between peers and uses TCP option 20 to carry the expected TTL value in each packet. The receiver checks the expected TTL value against the actual TTL value and discards packets with incorrect TTL values.
* You can implement BGP GTSM between R2 and R1. This is correct because R2 and R1 are EBGP peers and GTSM provides effective protection for directly connected EBGP sessions. The TTL of packets between directly connected EBGP peers is not changed by intermediate devices or routing protocols.
* BGP GTSM requires a TTL of 1 to be configured between neighbors. This is not correct because BGP GTSM requires a TTL of 255 to be configured between neighbors. The sender sets the TTL of packets to 255 and the receiver expects the TTL of packets to be 255 minus the configured hop count.
* BGP GTSM requires a TTL of 255 to be configured between neighbors. This is correct because BGP GTSM requires a TTL of 255 to be configured between neighbors. The sender sets the TTL of packets to 255 and the receiver expects the TTL of packets to be 255 minus the configured hop count.

NO.36 Exhibit

Referring to the exhibit, which three statements are correct about route 10 0 0.0/16 when using the default BGP advertisement rules’? (Choose three.)