How Many Questions Of JN0-664 Testing Engine

NEW QUESTION 1
Exhibit

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

• A. The PE is attached to a single local site.
• B. The connection has not flapped since it was initiated.
• C. There has been a VLAN ID mismatch.
• D. The PE router has the capability to pop flow labels

Answer: AD

Explanation:
According to 1 and2, 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.

NEW QUESTION 2
Which two statements are correct about reflecting inet-vpn unicast prefixes in BGP route reflection? (Choose two.)

• A. Route reflectors do not change any existing BGP attributes by default when advertising routes.
• B. A BGP peer does not require any configuration changes to become a route reflector client.
• C. Clients add their originator ID when advertising routes to their route reflector
• D. Route reflectors add their cluster ID to the AS path when readvertising client routes.

Answer: AB

Explanation:
Route reflection is a BGP feature that allows a router to reflect routes learned from one IBGP peer to another IBGP peer, without requiring a full-mesh IBGP topology. Route reflectors do not change any existing BGP attributes by default when advertising routes, unless explicitly configured to do so. A BGP peer does not require any configuration changes to become a route reflector client, only the route reflector needs to be configured with the client parameter under [edit protocols bgp group group-name neighbor neighbor- address] hierarchy level.

NEW QUESTION 3
Exhibit.

Referring to the exhibit; the 10.0.0.0/24 EBGP route is received on R5; however, the route is being hidden.
What are two solutions that will solve this problem? (Choose two.)

• A. On R4, create a policy to change the BGP next hop to itself and apply it to IBGP as an export policy
• B. Add the external interface prefix to the IGP routing tables
• C. Add the internal interface prefix to the BGP routing tables.
• D. On R4, create a policy to change the BGP next hop to 172.16.1.1 and apply it to IBGP as an export policy

Answer: AB

Explanation:
the default behavior for iBGP is to propagate EBGP-learned prefixes without changing the next-hop. This can cause issues if the next-hop is not reachable via the IGP. One solution is to use the next-hop self command on R4, which will change the next-hop attribute to its own loopback address. This way, R5 can reach the next-hop via the IGP and install the route in its routing table.
Another solution is to add the external interface prefix (120.0.4.16/30) to the IGP routing tables of R4 and R5. This will also make the next-hop reachable via the IGP and allow R5 to use the route. According to2, this is a possible workaround for a pure IP network, but it may not work well for an MPLS network.

NEW QUESTION 4
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 5
After a recent power outage, your manager asks you to investigate ways to automatically reduce the impact caused by suboptimal routing in your OSPF and OSPFv3 network after devices reboot.
Which three configuration statements accomplish this task? (Choose three.)

• A. set protocols ospf overload timeout 900
• B. set protocols ospf3 realm ipv4-unicast overload timeout 900
• C. set protocols ospf overload
• D. set protocols oapf3 overload timeout 900
• E. set protocols ospf3 overload

Answer: AE

Explanation:
To reduce the impact of suboptimal routing in OSPF and OSPFv3 after devices reboot, you can use the overload feature to prevent a router from being used as a transit router for a specified period of time. This allows the router to stabilize its routing table before forwarding traffic for other routers. To enable the overload feature, you need to do the following:
✑ For OSPF, configure the overload statement under [edit protocols ospf] hierarchy level. You can also specify a timeout value in seconds to indicate how long the router should remain in overload state after it boots up. For example, set protocols ospf overload timeout 900 means that the router will be in overload state for 15 minutes after it boots up.
✑ For OSPFv3, configure the overload statement under [edit protocols ospf3] hierarchy level. You can also specify a realm (ipv4-unicast or ipv6-unicast) and a timeout value in seconds to indicate how long the router should remain in overload state after it boots up for each realm. For example, set protocols ospf3 realm ipv4- unicast overload timeout 900 means that the router will be in overload state for 15 minutes after it boots up for IPv4 unicast routing.

NEW QUESTION 6
Exhibit

The environment is using BGP All devices are in the same AS with reachability redundancy Referring to the exhibit, which statement is correct?

• A. RR1 is peered to Client2 and RR2
• B. RR2 is in an OpenConfirm State until RR1 becomes unreachable.
• C. Client1 is peered to Client2 and Client3.
• D. Peering is dynamically discovered between all devices.

Answer: A

Explanation:
BGP route reflectors are BGP routers that are allowed to ignore the IBGP loop avoidance rule and advertise IBGP learned routes to other IBGP peers under specific conditions. BGP route reflectors can reduce the number of IBGP sessions and updates in a network by eliminating the need for a full mesh of IBGP peers. BGP route reflectors can have three types of peerings:
✑ EBGP neighbor: A BGP router that belongs to a different autonomous system (AS) than the route reflector.
✑ IBGP client neighbor: An IBGP router that receives reflected routes from the route reflector. A client does not need to peer with other clients or non-clients.
✑ IBGP non-client neighbor: An IBGP router that does not receive reflected routes from the route reflector. A non-client needs to peer with other non-clients and the route reflector.
In the exhibit, we can see that RR1 and RR2 are route reflectors in the same AS with reachability redundancy. They have two types of peerings: EBGP neighbors (R1 and R4) and IBGP client neighbors (Client1, Client2, and Client3). RR1 and RR2 are also peered with each other as IBGP non-client neighbors.

NEW QUESTION 7
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 8
Which two statements are correct regarding bootstrap messages that are forwarded within a PIM sparse mode domain? (Choose two.)

• A. Bootstrap messages are forwarded only to routers that explicitly requested the messages within the PIM sparse-mode domain
• B. Bootstrap messages distribute RP information dynamically during an RP election.
• C. Bootstrap messages are used to notify which router is the PIM RP
• D. Bootstrap messages are forwarded to all routers within a PIM sparse-mode domain.

Answer: BD

Explanation:
Bootstrap messages are PIM messages that are used to distribute rendezvous point (RP) information dynamically during an RP election. Bootstrap messages are sent by bootstrap routers (BSRs), which are routers that are elected to perform the RP discovery function for a PIM sparse-mode domain. Bootstrap messages contain information about candidate RPs and their multicast groups, as well as BSR priority and hash mask length. Bootstrap messages are forwarded to all routers within a PIM sparse-mode domain using hop-by-hop flooding.

NEW QUESTION 9
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 10
Exhibit

R1 and R8 are not receiving each other's routes
Referring to the exhibit, what are three configuration commands that would solve this problem? (Choose three.)

• A. Configure loops and advertise-peer-as on routers in AS 64497 and AS 64450.
• B. Configure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498.
• C. Configure as-override on advertisement from AS 64500 toward AS 64512.
• D. Configure remove-private on advertisements from AS 64497 toward AS 64498
• E. Configure remove-private on advertisements from AS 64500 toward AS 64499

Answer: BDE

Explanation:
The problem in this scenario is that R1 and R8 are not receiving each other’s routes because of private AS numbers in the AS path. Private AS numbers are not globally unique and are not advertised to external BGP peers. To solve this problem, you need to do the following:
✑ Configure loops on routers in AS 65412 and advertise-peer-as on routers in AS 64498. This allows R5 and R6 to advertise their own AS number (65412) instead of their peer’s AS number (64498) when sending updates to R7 and R8. This prevents a loop detection issue that would cause R7 and R8 to reject the routes from R5 and R62.
✑ Configure remove-private on advertisements from AS 64497 toward AS 64498 and from AS 64500 toward AS 64499. This removes any private AS numbers from the AS path before sending updates to external BGP peers. This allows R2 and R3 to receive the routes from R1 and R4, respectively3.

NEW QUESTION 11
Which two statements describe PIM-SM? (Choose two)

• A. Routers with receivers send join messages to their upstream neighbors.
• B. Routers without receivers must periodically prune themselves from the SPT.
• C. Traffic is initially flooded to all routers and an S,G is maintained for each group
• D. Traffic is only forwarded to routers that request to join the distribution tree.

Answer: AD

Explanation:
PIM sparse mode (PIM-SM) is a multicast routing protocol that uses a pull model to deliver multicast traffic. In PIM-SM, routers with receivers send join messages to their upstream neighbors toward a rendezvous point (RP) or a source-specific tree (SPT). The RP or SPT acts as the root of a shared distribution tree for a multicast group. Traffic is only forwarded to routers that request to join the distribution tree by sending join messages. PIM-SM does not flood traffic to all routers or prune routers without receivers, as PIM dense mode does.

NEW QUESTION 12
Exhibit

You are asked to exchange routes between R1 and R4 as shown in the exhibit. These two routers use the same AS number Which two steps will accomplish this task? (Choose two.)

• A. Configure the BGP group with the advertise-peer-as parameter on R1 and R4.
• B. Configure the BGP group with the as-override parameter on R2 and R3
• C. Configure the BGP group with the advertise-peer-as parameter on R2 and R3.
• D. Configure the BGP group with the as-override parameter on R1 and R4

Answer: AB

Explanation:
The advertise-peer-as parameter allows a router to advertise its peer’s AS number as part of the AS path attribute when sending BGP updates to other peers. This parameter is useful when two routers in the same AS need to exchange routes through another AS, such as in the case of R1 and R4. By configuring this parameter on R1 and R4, they can advertise each other’s AS number to R2 and R3, respectively.
The as-override parameter allows a router to replace the AS number of its peer with its own AS number when receiving BGP updates from that peer. This parameter is useful when two routers in different ASes need to exchange routes through another AS that has the same AS number as one of them, such as in the case of R2 and R3. By configuring this parameter on R2 and R3, they can override the AS number of R1 and R4 with their own AS number when sending BGP updates to each other.

NEW QUESTION 13
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 14
Which two statements are correct about a sham link? (Choose two.)

• A. It creates an OSPF multihop neighborship between two PE routers.
• B. It creates a BGP multihop neighborship between two PE routers.
• C. The PEs exchange Type 1 OSPF LSAs instead of Type 3 OSPF LSAs for the L3VPN routes
• D. The PEs exchange Type 3 OSPF LSAs instead of Type 1 OSPF LSAs for the L3VPN routes.

Answer: AC

Explanation:
A sham link is a logical link between two PE routers that belong to the same OSPF area but are connected through an L3VPN. A sham link makes the PE routers appear as if they are directly connected, and prevents OSPF from preferring an intra-area back door link over the VPN backbone. A sham link creates an OSPF multihop neighborship between the PE routers using TCP port 646. The PEs exchange Type 1 OSPF LSAs instead of Type 3 OSPF LSAs for the L3VPN routes, which allows OSPF to use the correct metric for route selection1.

NEW QUESTION 15
Exhibit

You are examining an L3VPN route that includes the information shown in the exhibit Which statement is correct in this scenario?

• A. The information shows a Type 1 route distinguisher.
• B. The information shows a Type 0 route distinguisher
• C. The information shows a Type 2 route distinguisher.
• D. The information shows a route target

Answer: B

Explanation:
The information shows a Type 0 route distinguisher, which is one of the three types of route distinguishers defined by RFC 4364. A route distinguisher is a 64-bit value that is prepended to an IPv4 address to create a VPN-IPv4 address, which is unique within a VPN routing and forwarding (VRF) table. A Type 0 route distinguisher has two fields: an administrator subfield (2 bytes) and an assigned number subfield (6 bytes). The administrator subfield can be an AS number or an IP address, and the assigned number subfield can be any value assigned by the administrator. In this example, the administrator subfield is 65530 (an AS number) and the assigned number subfield is 1.

NEW QUESTION 16
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?

• A. Under the family inet labeled-unicast hierarchy, add the explicit null parameter.
• B. Under the protocols ospf hierarchy, add the traffic-engineering parameter.
• C. Under the family inet labeled-unicast hierarchy, add the resolve-vpn parameter.
• D. Under the protocols mpls hierarchy, add the traffic-engineering parameter

Answer: C

Explanation:
The resolve-vpn parameter is a BGP option that allows a router to resolve labeled VPN-IPv4 routes using unlabeled IPv4 routes received from another BGP peer with family inet labeled-unicast configured. This option enables interprovider VPNs without requiring MPLS labels between ASBRs or using VRF tables on ASBRs. In this scenario, you need to configure the resolve-vpn parameter under [edit protocols bgp group external family inet labeled-unicast] hierarchy level on both ASBRs.

NEW QUESTION 17
Exhibit

Referring to the exhibit, what do the brackets [ ] in the AS path identify?

• A. They identify the local AS number associated with the AS path if configured on the router, or if AS path prepending is configured
• B. They identify an AS set, which are groups of AS numbers in which the order does not matter
• C. They identify that the autonomous system number is incomplete and awaiting more information from the BGP protocol.
• D. They identify that a BGP confederation is being used to ensure that there are no routing loops.

Answer: B

Explanation:
The brackets [ ] in the AS path identify an AS set, which are groups of AS numbers in which the order does not matter. An AS set is used when BGP aggregates routes from different ASs into a single prefix. For example, if BGP aggregates routes 10.0.0.0/16 and 10.1.0.0/16 from AS 100 and AS 200, respectively, into a single prefix 10.0.0.0/15, then the AS path for this prefix will be [100 200]. An AS set reduces the length of the AS path and prevents routing loops.

NEW QUESTION 18
By default, which statement is correct about OSPF summary LSAs?

• A. All Type 2 and Type 7 LSAs will be summanzed into a single Type 5 LSA
• B. The area-range command must be installed on all routers.
• C. Type 3 LSAs are advertised for routes in Type 1 LSAs.
• D. The metric associated with a summary route will be equal to the lowest metric associated with an individual contributing route

Answer: C

Explanation:
OSPF uses different types of LSAs to describe different aspects of the network topology. Type 1 LSAs are also known as router LSAs, and they describe the links and interfaces of a router within an area. Type 3 LSAs are also known as summary LSAs, and they describe routes to networks outside an area but within the same autonomous system (AS). By default, OSPF will summarize routes from Type 1 LSAs into Type 3 LSAs when advertising them across area boundaries .

NEW QUESTION 19
Exhibit

The network shown in the exhibit is based on IS-IS Which statement is correct in this scenario?

• A. The NSEL byte for Area 0001 is 00.
• B. The area address is two bytes.
• C. The routers are using unnumbered interfaces
• D. The system IDofR1_2 is 192.168.16.1

Answer: A

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 addresses to identify routers and areas: system ID and area address. The system ID is a unique identifier for each router in an IS-IS domain. The system ID is 6 octets long and can be derived from the MAC address or manually configured. The area address is a variable-length identifier for each area in an IS-IS domain. The area address can be 1 to 13 octets long and is composed of high-order octets of the address. An IS-IS instance may be assigned multiple area addresses, which are considered synonymous. Multiple synonymous area addresses are useful when merging or splitting areas in the domain1. In this question, we have a network based on IS-IS with four routers (R1_1, R1_2, R2_1, and R2_2) belonging to area 0001. The area address for area 0001 is 49.0001. The NSEL byte for area 0001 is the last octet of the address, which is 01. The NSEL byte stands for Network Service Access Point Selector (NSAP Selector) and indicates the type of service requested from the network layer2. Therefore, the correct statement in this scenario is that the NSEL byte for area 0001 is 01.
References: 1: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_isis/configuration/xe-16/irs-xe-16-book/irs-ovrvw-cf.html 2:
https://www.juniper.net/documentation/us/en/software/junos/is-is/topics/concept/is-is-routing-overview.html

NEW QUESTION 20
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