A Review Of Best Quality JN0-664 Test

NEW QUESTION 1
An interface is configured with a behavior aggregate classifier and a multifield classifier How will the packet be processed when received on this interface?

• A. The packet will be discarded.
• B. The packet will be processed by the BA classifier first, then the MF classifier.
• C. The packet will be forwarded with no classification changes.
• D. The packet will be processed by the MF classifier first, then the BA classifier.

Answer: C

Explanation:
behavior aggregate (BA) classifiers and multifield (MF) classifiers are two types of classifiers that are used to assign packets to a forwarding class and a loss priority based on different criteria. The forwarding class determines the output queue for a packet. The loss priority is used by a scheduler to control packet discard during periods of congestion.
A BA classifier maps packets to a forwarding class and a loss priority based on a fixed- length field in the packet header, such as DSCP, IP precedence, MPLS EXP, or IEEE 802.1p CoS bits. A BA classifier is computationally efficient and suitable for core devices that handle high traffic volumes. A BA classifier is useful if the traffic comes from a trusted source and the CoS value in the packet header is trusted.
An MF classifier maps packets to a forwarding class and a loss priority based on multiple fields in the packet header, such as source address, destination address, protocol type, port number, or VLAN ID. An MF classifier is more flexible and granular than a BA classifier and can match packets based on complex filter rules. An MF classifier is suitable for edge devices that need to classify traffic from untrusted sources or rewrite packet headers.
You can configure both a BA classifier and an MF classifier on an interface. If you do this, the BA classification is performed first and then the MF classification. If the two classification results conflict, the MF classification result overrides the BA classification result.
Based on this information, we can infer the following statements:
✑ The packet will be discarded. This is not correct because the packet will not be discarded by the classifiers unless it matches a filter rule that specifies discard as an action. The classifiers only assign packets to a forwarding class and a loss priority based on their match criteria.
✑ The packet will be processed by the BA classifier first, then the MF classifier. This is correct because if both a BA classifier and an MF classifier are configured on an interface, the BA classification is performed first and then the MF classification. If they conflict, the MF classification result overrides the BA classification result.
✑ The packet will be forwarded with no classification changes. This is not correct because the packet will be classified by both the BA classifier and the MF classifier if they are configured on an interface. The final classification result will determine which output queue and which discard policy will be applied to the packet.
✑ The packet will be processed by the MF classifier first, then the BA classifier. This is not correct because if both a BA classifier and an MF classifier are configured on an interface, the BA classification is performed first and then the MF classification. If they conflict, the MF classification result overrides the BA classification result.

NEW QUESTION 2
Exhibit

Referring to the exhibit, a working L3VPN exists that connects VPN-A sites CoS is configured correctly to match on the MPLS EXP bits of the LSP, but when traffic is sent from Site-1 to Site-2, PE-2 is not classifying the traffic correctly
What should you do to solve the problem?

• A. Configure the explicit-null statement on PE-1.
• B. Configure the explicit-null statement on PE-2
• C. Configure VPN prefix mapping for the PE-1_to_PE-2 LSP
• D. Set a static CoS value for the PE-1_to_PE-2 LSP

Answer: A

Explanation:
The explicit-null statement enables the PE router to send an MPLS label with a value of 0 (explicit null) instead of an IP header for packets destined to the VPN customer sites. This allows the penultimate hop router (the router before the egress PE router) to preserve the EXP bits of the MPLS label and pass them to the egress PE router. The egress PE router can then use these EXP bits to classify the traffic according to the CoS policy2. In this example, PE-1 should configure the explicit-null statement under [edit protocols mpls label-switched-path PE-1_to_PE-2] hierarchy level.

NEW QUESTION 3
Which statement is correct about IS-IS when it performs the Dijkstra algorithm?

• A. The local router moves its own local tuples into the candidate database
• B. When a new neighbor ID in the tree database matches a router ID in the LSDB, the neighbor ID is moved to the candidate database
• C. Tuples with the lowest cost are moved from the tree database to the LSDB.
• D. The algorithm will stop processing once the tree database is empty.

Answer: A

Explanation:
IS-IS is a link-state routing protocol that uses the Dijkstra algorithm to compute the shortest paths between nodes in a network. The Dijkstra algorithm maintains three data structures: a tree database, a candidate database, and a link-state database (LSDB). The tree database contains the nodes that have been visited and their shortest distances from the source node. The candidate database contains the nodes that have not been visited yet and their tentative distances from the source node. The LSDB contains the topology information of the network, such as the links and their costs.
The Dijkstra algorithm works as follows:
✑ The local router moves its own local tuples into the tree database. A tuple consists of a node ID, a distance, and a parent node ID. The local router’s tuple has a distance of zero and no parent node.
✑ The local router moves its neighbors’ tuples into the candidate database. The neighbors’ tuples have distances equal to the costs of the links to them and parent node IDs equal to the local router’s node ID.
✑ The local router selects the tuple with the lowest distance from the candidate database and moves it to the tree database. This tuple becomes the current node.
✑ The local router updates the distances of the current node’s neighbors in the candidate database by adding the current node’s distance to the link costs. If a shorter distance is found, the parent node ID is also updated.
✑ The algorithm repeats steps 3 and 4 until either the destination node is reached or the candidate database is empty.

NEW QUESTION 4
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?

• A. 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.
• B. You must create a unique Layer 2 VPN routing instance for each site on the PE-2 device.
• C. You must use separate physical interfaces to connect PE-2 to each site.
• D. 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.

Answer: D

Explanation:
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 BGP Layer 2 VPNs, each site has a unique site ID that identifies it within a VFI. The site ID can be manually configured or automatically assigned by the PE device. By default, the site ID is automatically assigned based on the order that you add the interfaces to the site configuration. The first interface added to a site configuration has a site ID of 1, the second interface added has a site ID of 2, and so on.
Option D is correct because 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. Option A is not correct because by default on PE-2, the site’s local ID is automatically assigned a value of 0 and does not need to be configured to match the total number of attached sites. Option B is not correct because you do not need to create a unique Layer 2 VPN routing instance for each site on the PE-2 device. You can create one routing instance for all sites within a VFI. Option C is not correct because you do not need to use separate physical interfaces to connect PE-2 to each site. You can use subinterfaces or service instances on a single physical interface.

NEW QUESTION 5
Exhibit

Referring to the exhibit, which two statements are true? (Choose two.)

• A. This route is learned through EBGP
• B. This is an EVPN Type-2 route.
• C. The device advertising this route into EVPN is 192.168.101.5.
• D. The devices advertising this route into EVPN are 10 0 2 12 and 10.0.2.22.

Answer: BC

Explanation:
This is an EVPN Type-2 route, also called a MAC/IP advertisement route, that is used to advertise host IP and MAC address information to other VTEPs in an EVPN network. The route type field in the EVPN NLRI has a value of 2, indicating a Type-2 route. The device advertising this route into EVPN is 192.168.101.5, which is the IP address of the VTEP that learned the host information from the local CE device. This IP address is carried in the MPLS label field of the route as part of the VXLAN encapsulation.

NEW QUESTION 6
Which two statements are correct about IS-IS interfaces? (Choose two.)

• A. If a broadcast interface is in both L1 and L2, one combined hello message is sent for both levels.
• B. If a point-to-point interface is in both L1 and L2, separate hello messages are sent for each level.
• C. If a point-to-point interface is in both L1 and L2, one combined hello message is sent for both levels.
• D. If a broadcast interface is in both L1 and L2, separate hello messages are sent for each level

Answer: BD

Explanation:
IS-IS supports two levels of routing: Level 1 (intra-area) and Level 2 (interarea). An IS-IS router can be either Level 1 only, Level 2 only, or both Level 1 and Level 2. A router that is both Level 1 and Level 2 is called a Level 1-2 router. A Level 1-2 router sends separate hello messages for each level on both point-to-point and broadcast interfaces1. A point-to-point interface provides a connection between a single source and a single destination. A broadcast interface behaves as if the router is connected to a LAN.

NEW QUESTION 7
Exhibit

Referring to the exhibit, PE-1 and PE-2 are getting route updates for VPN-B when neither of them service that VPN
Which two actions would optimize this process? (Choose two.)

• A. Configure the family route-target statement on the PEs.
• B. Configure the family route-target statement on the RR
• C. Configure the resolution rib bgp . 13vpn . 0 resolution-ribs ine
• D. 0 Statement on the PEs.
• E. Configure the resolution rib bgp.l3vpn.O resolution-ribs ine
• F. 0 Statement on the RR

Answer: BD

Explanation:
BGP route target filtering is a technique that reduces the number of routers that receive VPN routes and route updates, helping to limit the amount of overhead associated with running a VPN. BGP route target filtering is based on the exchange of the route-target address family, which contains information about the VPN membership of each PE device. Based on this information, a PE device can decide whether to accept or reject VPN routes from another PE device.
BGP route target filtering can be configured on PE devices or on route reflectors (RRs). Configuring BGP route target filtering on RRs is more efficient and scalable, as it reduces the number of BGP sessions and updates between PE devices. To configure BGP route target filtering on RRs, the following steps are required:
✑ Configure the family route-target statement under the BGP group or neighbor configuration on the RRs. This enables the exchange of the route-target address family between the RRs and their clients (PE devices).
✑ Configure the resolution rib bgp.l3vpn.0 resolution-ribs inet.0 statement under the routing-options configuration on the RRs. This enables the RRs to resolve next hops for VPN routes using the inet.0 routing table.
✑ Configure an export policy for BGP route target filtering under the routing-options configuration on the RRs. This policy controls which route targets are advertised to each PE device based on their VPN membership.

NEW QUESTION 8
You are responding to an RFP for a new MPLS VPN implementation. The solution must use LDP for signaling and support Layer 2 connectivity without using BGP The solution must be scalable and support multiple VPN connections over a single MPLS LSP The customer wants to maintain all routing for their Private network
In this scenario, which solution do you propose?

• A. circuit cross-connect
• B. BGP Layer 2 VPN
• C. LDP Layer 2 circuit
• D. translational cross-connect

Answer: C

Explanation:
AToM (Any Transport over MPLS) is a framework that supports various Layer 2 transport types over an MPLS network core. One of the transport types supported by AToM is LDP Layer 2 circuit, which is a point-to-point Layer 2 connection that uses LDP for signaling and MPLS for forwarding. LDP Layer 2 circuit can support Layer 2 connectivity without using BGP and can be scalable and efficient by using a single MPLS LSP for multiple VPN connections. The customer can maintain all routing for their private network by using their own CE switches.

NEW QUESTION 9
Which two statements about IS-IS are correct? (Choose two.)

• A. PSNPs are flooded periodically.
• B. PSNPs contain only descriptions of LSPs.
• C. CSNPs are flooded periodically
• D. CSNPs contain only descriptions of LSPs.

Answer: BC

Explanation:
IS-IS is an interior gateway protocol that uses link-state routing to exchange routing information among routers within a single autonomous system. IS-IS uses two types of packets to synchronize link-state databases among routers: Link State Packets (LSPs) and Partial Sequence Number Packets (PSNPs). LSPs contain information about the state and cost of links in the network, and are flooded periodically throughout the network. PSNPs are used to acknowledge receipt of LSPs and request retransmission of missing or corrupted LSPs. PSNPs contain only descriptions of LSPs, such as their sequence numbers and checksums3. IS-IS also uses another type of packet called Complete Sequence Number Packets (CSNPs), which are used to summarize the entire link-state database at regular intervals or when a new adjacency is formed. CSNPs are flooded periodically throughout the network and contain only descriptions of LSPs4. Therefore, PSNPs contain only descriptions of LSPs and CSNPs are flooded periodically. References: 3: https://www.juniper.net/documentation/us/en/software/junos/routing-
policy/topics/concept/routing-policy-is-is-partial-sequence-number-packet-psnp.html 4: https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/routing-policy-is-is-complete-sequence-number-packet-csnp.html

NEW QUESTION 10
Which statement is true regarding BGP FlowSpec?

• A. It uses a remote triggered black hole to protect a network from a denial-of-service attack.
• B. It uses dynamically created routing policies to protect a network from denial-of-service attacks
• C. It is used to protect a network from denial-of-service attacks dynamically
• D. It verifies that the source IP of the incoming packet has a resolvable route in the routing table

Answer: B

Explanation:
BGP FlowSpec is a feature that extends the Border Gateway Protocol (BGP) to enable routers to exchange traffic flow specifications, allowing for more precise control of network traffic. The BGP FlowSpec feature enables routers to advertise and receive information about specific flows in the network, such as those originating from a particular source or destined for a particular destination. Routers can then use this information to construct traffic filters that allow or deny packets of a certain type, rate limit flows, or perform other actions1. BGP FlowSpec can also help in filtering traffic and taking action against distributed denial of service (DDoS) attacks by dropping the DDoS traffic or diverting it to an analyzer2. BGP FlowSpec rules are internally converted to equivalent Cisco Common Classification Policy Language (C3PL) representing corresponding match and action parameters2. Therefore, BGP FlowSpec uses dynamically created routing policies to protect a network from denial-of-service attacks.
References: 1: https://www.networkingsignal.com/what-is-bgp-flowspec/ 2: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-16/irg-xe-16-book/bgp-flowspec-route-reflector-support.html

NEW QUESTION 11
Exhibit

Which two statements are true about the OSPF adjacency displayed in the exhibit? (Choose two.)

• A. There is a mismatch in the hello interval parameter between routers R1 and R2
• B. There is a mismatch in the dead interval parameter between routers R1 and R2.
• C. There is a mismatch in the OSPF hold timer parameter between routers R1 and R2.
• D. There is a mismatch in the poll interval parameter between routers R1 and R2.

Answer: AB

Explanation:
The hello interval is the time interval between two consecutive hello packets sent by an OSPF router on an interface. The dead interval is the time interval after which a neighbor is declared down if no hello packets are received from it. These parameters must match between two OSPF routers for them to form an adjacency. In the exhibit, router R1 has a hello interval of 10 seconds and a dead interval of 40 seconds, while router R2 has a hello interval of 30 seconds and a dead interval of 120 seconds. This causes a mismatch and prevents them from becoming neighbors23.

NEW QUESTION 12
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.)

• A. The drop probability jumps immediately from 20% to 60% when the queue level reaches 75% full.
• B. The drop probability gradually increases from 20% to 60% as the queue level increases from 50% full to 75% full
• C. To use this drop profile, you reference it in a scheduler.
• D. To use this drop profile, you apply it directly to an interface.

Answer: BC

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; } }

NEW QUESTION 13
Exhibit

R4 is directly connected to both RPs (R2 and R3) R4 is currently sending all ,o,ns upstream to R3 but you want all joins to go to R2 instead Referring to the exhibit, which configuration change will solve this issue?

• A. Change the bootstrap priority on R2 to be higher than R3
• B. Change the default route in inet.2 on R4 from R3 as the next hop to R2
• C. Change the local address on R2 to be higher than R3.
• D. Change the group-range to be more specific on R2 than R3.

Answer: A

Explanation:
PIM Bootstrap Router (BSR) is a mechanism that allows PIM routers to discover and announce rendezvous point (RP) information for multicast groups. BSR uses two roles: candidate BSR and candidate RP. Candidate BSR is the router that collects information from all available RPs in the network and advertises it throughout the network. Candidate RP is the router that wants to become the RP and registers itself with the BSR. There can be only one active BSR in the network, which is elected based on the highest priority or highest IP address if the priority is the same. The BSR priority can be configured manually or assigned automatically. The default priority is 0 and the highest priority is 2515. In this question, R4 is directly connected to both RPs (R2 and R3) and is currently sending all joins upstream to R3 but we want all joins to go to R2 instead. To achieve this, we need to change the BSR priority on R2 to be higher than R3 so that R2 becomes the active BSR and advertises its RP information to R4.
Reference: 1: https://study-ccnp.com/multicast-rendezvous-points-explained/

NEW QUESTION 14
You are configuring a BGP signaled Layer 2 VPN across your MPLS enabled core network. In this scenario, which statement is correct?

• A. You must assign a unique site number to each attached site's configuration.
• B. This type of VPN only supports Ethernet interfaces when connecting to CE devices.
• C. This type of VPN requires the support of the inet-vpn NLRI on all core BGP devices
• D. You must use the same route-distinguiaher value on both PE devices.

Answer: C

Explanation:
BGP signaled Layer 2 VPN is a type of VPN that uses BGP to distribute VPN labels and information for Layer 2 connectivity between sites over an MPLS network. BGP signaled Layer 2 VPN requires the support of the l2vpn NLRI on all core BGP devices1. The l2vpn NLRI is a new address family that carries Layer 2 VPN information such as the VPN identifier, the attachment circuit identifier, and the route distinguisher. The l2vpn NLRI is used for both auto-discovery and signaling of Layer 2 VPNs2. In this scenario, we are configuring a BGP signaled Layer 2 VPN across an MPLS enabled core network.
Therefore, we need to ensure that all core BGP devices support the l2vpn NLRI. References: 1: https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/topics/concept/vpn-layer-2-overview.html 2: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_l2_vpns/configuration/xe-16/mp-l2-vpns-xe-16-book/vpls-bgp-signaling-l2vpn- inter-as-option-a.html

NEW QUESTION 15
Exhibit

You want Site 1 to access three VLANs that are located in Site 2 and Site 3 The customer- facing interface on the PE-1 router is configured for Ethernet-VLAN encapsulation.
What is the minimum number of L2VPN routing instances to be configured to accomplish this task?

• A. 1
• B. 3
• C. 2
• D. 6

Answer: B

Explanation:
To allow Site 1 to access three VLANs that are located in Site 2 and Site 3, you need to configure three L2VPN routing instances on PE-1, one for each VLAN. Each L2VPN routing instance will have a different VLAN ID and a different VNI for VXLAN encapsulation. Each L2VPN routing instance will also have a different vrf-target export value to identify which VPN routes belong to which VLAN. This way, PE-1 can forward traffic from Site 1 to Site 2 and Site 3 based on the VLAN tags and VNIs.

NEW QUESTION 16
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