JN0-664 | Actual Juniper JN0-664 Free Demo Online

NEW QUESTION 1
You want to ensure that L1 IS-IS routers have only the most specific routes available from L2 IS-IS routers. Which action accomplishes this task?

• A. Configure the ignore-attached-bit parameter on all L2 routers.
• B. Configure all routers to allow wide metrics.
• C. Configure all routers to be L1.
• D. Configure the ignore-attached-bit parameter on all L1 routers

Answer: D

Explanation:
The attached bit is a flag in an IS-IS LSP that indicates whether a router is connected to another area or level (L2) of the network. By default, L2 routers set this bit when they advertise their LSPs to L1 routers, and L1 routers use this bit to select a default route to reach other areas or levels through L2 routers. However, this may result in suboptimal routing if there are multiple L2 routers with different paths to other areas or levels. To ensure that L1 routers have only the most specific routes available from L2 routers, you can configure the ignore-attached-bit parameter on all L1 routers. This makes L1 routers ignore the attached bit and install all interarea routes learned from L2 routers in their routing tables.

NEW QUESTION 2
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 3
What is the correct order of packet flow through configurable components in the Junos OS CoS features?

• A. Multifield Classifier -> Behavior Aggregate Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Rewrite Marker -> Scheduler/Shaper/RED
• B. Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker
• C. Behavior Aggregate Classifier -> Input Policer -> Multifield Classifier -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker
• D. Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Scheduler/Shaper/RED -> Output Policer -> Rewrite Marker

Answer: C

Explanation:
The correct order of packet flow through configurable components in the Junos OS CoS features is as follows:
✑ Behavior Aggregate Classifier: This component uses a single field in a packet header to classify traffic into different forwarding classes and loss priorities based on predefined or user-defined values.
✑ Input Policer: This component applies rate-limiting and marking actions to incoming traffic based on the forwarding class and loss priority assigned by the classifier.
✑ Multifield Classifier: This component uses multiple fields in a packet header to classify traffic into different forwarding classes and loss priorities based on user- defined values and filters.
✑ Forwarding Policy Options: This component applies actions such as load balancing, filtering, or routing to traffic based on the forwarding class and loss priority assigned by the classifier.
✑ Fabric Scheduler: This component schedules traffic across the switch fabric based on the forwarding class and loss priority assigned by the classifier.
✑ Output Policer: This component applies rate-limiting and marking actions to outgoing traffic based on the forwarding class and loss priority assigned by the classifier.
✑ Scheduler/Shaper/RED: This component schedules, shapes, and drops traffic at the egress interface based on the forwarding class and loss priority assigned by the classifier.
✑ Rewrite Marker: This component rewrites the code-point bits of packets leaving an interface based on the forwarding class and loss priority assigned by the classifier.

NEW QUESTION 4
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 5
Your organization manages a Layer 3 VPN for multiple customers To support advanced route than one BGP community on advertised VPN routes to remote PE routers.
Which routing-instance configuration parameter would support this requirement?

• A. vrf-export
• B. vrf-import
• C. vrf-target export
• D. vrf-target import

Answer: C

Explanation:
The vrf-target export parameter is used to specify one or more BGP extended community attributes that are attached to VPN routes when they are exported from a VRF routing instance to remote PE routers. This parameter allows you to control which VPN routes are accepted by remote PE routers based on their import policies. You can specify more than one vrf-target export value for a VRF routing instance to support advanced route filtering or route leaking scenarios.

NEW QUESTION 6
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 7
When using OSPFv3 for an IPv4 environment, which statement is correct?

• A. OSPFv3 only supports IPv4.
• B. OSPFv3 supports both IPv6 and IPv4, but not in the same routing instance.
• C. OSPFv3 is not backward compatible with IPv4
• D. OSPFv3 supports IPv4 only on interfaces with family inet6 defined

Answer: C

Explanation:
OSPFv3 is an extension of OSPFv2 that supports IPv6 routing and addressing. OSPFv3 is not backward compatible with IPv4 because it uses a different packet format and a different link-state advertisement (LSA) structure than OSPFv2. OSPFv3 also uses IPv6 link-local addresses as router IDs and neighbor addresses, instead of IPv4 addresses. To use OSPFv3 for an IPv4 environment, you need to enable the IPv4 unicast address family under [edit protocols ospf3] hierarchy level and configure IPv4 addresses on the interfaces.

NEW QUESTION 8
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.)

• A. Source2 will use RP2 and Received will use RP2 for group 224.2.2.2.
• B. Source2 will use RP1 and Receiver2 will use RP1 for group 224.2.2.2.
• C. Source1 will use RP1 and Receiver1 will use RP1 for group 224.1.1.1.
• D. Source1 will use RP1 and Receiver1 will use RP2 for group 224.1 1 1

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 9
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)

• A. You can implement BGP GTSM between R2, R3, and R4
• B. BGP GTSM requires a firewall filter to discard packets with incorrect TTL.
• C. You can implement BGP GTSM between R2 and R1.
• D. BGP GTSM requires a TTL of 1 to be configured between neighbors.
• E. BGP GTSM requires a TTL of 255 to be configured between neighbors.

Answer: ADE

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.

NEW QUESTION 10
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 11
Exhibit

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

• A. This VPN connects customer sites that use different AS numbers.
• B. This VPN connects customer sites that use the same AS number
• C. A Layer 2 VPN is configured.
• D. A Layer 3 VPN is configured.

Answer: AD

Explanation:
The configuration shown in the exhibit is for a Layer 3 VPN that connects customer sites that use different AS numbers. A Layer 3 VPN is a type of VPN that uses MPLS labels to forward packets across a provider network and BGP to exchange routing information between PE routers and CE routers. A Layer 3 VPN allows customers to use different routing protocols and AS numbers at their sites, as long as they can peer with BGP at the PE-CE interface. In this example, CE-1 is using AS 65530 and CE-2 is using AS 65531, but they can still communicate through the VPN because they have BGP sessions with PE-1 and PE-2, respectively.

NEW QUESTION 12
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 13
A packet is received on an interface configured with transmission scheduling. One of the configured queues In this scenario, which two actions will be taken by default on a Junos device? (Choose two.)

• A. The excess traffic will be discarded
• B. The exceeding queue will be considered to have negative bandwidth credit.
• C. The excess traffic will use bandwidth available from other queueses
• D. The exceeding queue will be considered to have positive bandwidth credit

Answer: AB

Explanation:
Transmission scheduling is a CoS feature that allows you to allocate bandwidth among different queues on an interface. Each queue has a configured bandwidth percentage that determines how much of the available bandwidth it can use. If a queue exceeds its allocated bandwidth, it is considered to have negative bandwidth credit and its excess traffic will be discarded by default. If a queue does not use all of its allocated bandwidth, it is considered to have positive bandwidth credit and its unused bandwidth can be shared by other queues.

NEW QUESTION 14
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 15
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.)

• A. By default, the next-hop value for these routes is not changed by ISP-A before being sent to R3.
• B. The BGP local-preference value that is used by ISP-A is not advertised to R3.
• C. All BGP attribute values must be removed before receiving the routes.
• D. The next-hop value for these routes is changed by ISP-A before being sent to R3.

Answer: AB

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

NEW QUESTION 16
Exhibit

CE-1 and CE-2 are part of a VPLS called Customer1 No connectivity exists between CE-1 and CE-2. In the process of troubleshooting, you notice PE-1 is not learning any routes for this VPLS from PE-2, and PE-2 is not learning any routes for this VPLS from PE-1.

• A. The route target must match on PE-1 and PE-2.
• B. The route distinguisher must match on PE-1 and PE-2.
• C. The instance type should be changed to I2vpn.
• D. The no-tunnel-services statement should be deleted on both PEs.

Answer: A

Explanation:
VPLS is a technology that provides Layer 2 VPN services over an MPLS network. VPLS uses BGP as its control protocol to exchange VPN membership information between PE routers. The route target is a BGP extended community attribute that identifies which VPN a route belongs to. The route target must match on PE routers that participate in the same VPLS instance, otherwise they will not accept or advertise routes for that VPLS.

NEW QUESTION 17
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 18
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