[2024] JN0-664 Actual Exam Dumps, JN0-664 Practice Test
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NEW QUESTION # 54
Which statement is correct about IS-IS when it performs the Dijkstra algorithm?
- A. 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
- B. The local router moves its own local tuples into 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: B
NEW QUESTION # 55
Exhibit
Which two statements about the output shown in the exhibit are correct? (Choose two.)
- A. The PE router has the capability to pop flow labels
- B. The connection has not flapped since it was initiated.
- C. The PE is attached to a single local site.
- D. There has been a VLAN ID mismatch.
Answer: A,C
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.
NEW QUESTION # 56
Which two statements are correct about reflecting inet-vpn unicast prefixes in BGP route reflection? (Choose two.)
- A. A BGP peer does not require any configuration changes to become a route reflector client.
- B. Route reflectors do not change any existing BGP attributes by default when advertising routes.
- C. Route reflectors add their cluster ID to the AS path when readvertising client routes.
- D. Clients add their originator ID when advertising routes to their route reflector.
Answer: A,B
NEW QUESTION # 57
Referring to the exhibit, which statement is correct?
- A. The vrf-target configuration will stop routes from being shared between CE-1 and CE-2.
- B. The route-distinguisher configuration will allow overlapping routes to be shared between CE-1 and CE-2.
- C. The route-distinguisher configuration will stop routes from being shared between CE-1 and CE-2.
- D. The vrf-target configuration will allow routes to be shared between CE-1 and CE-2.
Answer: D
NEW QUESTION # 58
Which origin code is preferred by BGP?
- A. Internal
- B. Null
- C. External
- D. Incomplete
Answer: A
Explanation:
Prefer the route with the lower origin code.
Routes learned from an IGP have a lower origin code than those learned from an exterior gateway protocol (EGP), and both have lower origin codes than incomplete routes (routes whose origin is unknown).
https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/bgp/topics/concept/routing- protocols-address-representation.html
NEW QUESTION # 59
A network designer would like to advertise a single summary route from R4 to IS-IS level 2 neighbors as shown in the exhibit, but the configuration is not working.
Which three configuration changes will accomplish this task? (Choose three.)
- A. delete policy-options policy-statement summary-v6 term DC-routes from route-filter
2001:db5:a:fa00::/61 longer - B. delete protocols isis export summary-v6
- C. set policy-options policy-statement summary-v6 term suppress then reject
- D. set policy-options policy-statement summary-v6 term DC-routes from route-filter
2001:dbS:a:fa00::/6l exact - E. set protocols isis import summary-v6
Answer: A,C,D
NEW QUESTION # 60
In which two ways does OSPF prevent routing loops in multi-area networks? (Choose two.)
- A. The LFA algorithm prunes all looped paths within an area.
- B. The SPF algorithm prunes looped paths within an area.
- C. All areas are required to connect to area 0.
- D. All areas are required to connect as a full mesh.
Answer: B,C
Explanation:
Explanation
OSPF is an interior gateway protocol that uses link-state routing to exchange routing information among routers within a single autonomous system. OSPF prevents routing loops in multi-area networks by using two methods: area hierarchy and SPF algorithm. Area hierarchy is the concept of dividing a large OSPF network into smaller areas that are connected to a backbone area (area 0). This reduces the amount of routing information that each router has to store and process, and also limits the scope of link-state updates within each area. All areas are required to connect to area 0 either directly or through virtual links2. SPF algorithm is the method that OSPF uses to calculate the shortest path to each destination in the network based on link-state information. The SPF algorithm runs on each router and builds a shortest-path tree that represents the topology of the network from the router's perspective. The SPF algorithm prunes looped paths within an area by choosing only one best path for each destination3.
References: 2:
https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/concept/ospf-area-overview.html 3:
https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/concept/ospf-spf-algorithm-overview.ht
NEW QUESTION # 61
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 RP1 and Receiver2 will use RP1 for group 224.2.2.2.
- B. Source2 will use RP2 and Received will use RP2 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: B,C
Explanation:
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 # 62
Which two statements are correct about IS-IS interfaces? (Choose two.)
- A. If a broadcast interface is in both L1 and L2, separate hello messages are sent for each level
- B. If a point-to-point interface is in both L1 and L2, one combined hello message is sent for both levels.
- C. If a broadcast interface is in both L1 and L2, one combined hello message is sent for both levels.
- D. If a point-to-point interface is in both L1 and L2, separate hello messages are sent for each level.
Answer: A,D
Explanation:
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 # 63
Exhibit
Referring to the exhibit, CE-1 is providing NAT services for the hosts at Site 1 and you must provide Internet access for those hosts Which two statements are correct in this scenario? (Choose two.)
- A. You must configure a static route in the main routing instance for the 203.0.113.1/32 prefix that uses the VPN-A.inet.0 table as the next hop.
- B. You must configure a RIB group on PE-1 to leak the 10 1 2.0/24 prefix from the VPN-A.inet.0 table to the inet.0 table.
- C. You must configure a RIB group on PE-1 to leak a default route from the inet.0 table to the VPN-A.inet.0 table.
- D. You must configure a static route in the main routing instance for the 10 1 2.0/24 prefix that uses the VPN-A.inet.0 table as the next hop
Answer: A,C
NEW QUESTION # 64
Exhibit
R2 is receiving the same route from R1 and R3. You must ensure that you can load balance traffic for that route.
Referring to the exhibit, which configuration change will allow load balancing?
- A. Apply the prepend policy as an import policy under group R1.
- B. Configure the multipath multiple-as parameter under the global BGP configuration.
- C. Configure the multipath parameter under the global BGP configuration.
- D. Apply the prepend policy as an import policy under group R3.
Answer: B
NEW QUESTION # 65
You are asked to protect your company's customers from amplification attacks. In this scenario, what is Juniper's recommended protection method?
- A. BGP FlowSpec
- B. ASN prepending
- C. unicast Reverse Path Forwarding
- D. destination-based Remote Triggered Black Hole
Answer: D
Explanation:
amplification attacks are a type of distributed denial-of-service (DDoS) attack that exploit the characteristics of certain protocols to amplify the traffic sent to a victim. For example, an attacker can send a small DNS query with a spoofed source IP address to a DNS server, which will reply with a much larger response to the victim. This way, the attacker can generate a large amount of traffic with minimal resources.
One of the methods to protect against amplification attacks is destination-based Remote Triggered Black Hole (RTBH) filtering. This technique allows a network operator to drop traffic destined to a specific IP address or prefix at the edge of the network, thus preventing it from reaching the victim and consuming bandwidth and resources. RTBH filtering can be implemented using BGP to propagate a special route with a next hop of
192.0.2.1 (a reserved address) to the edge routers. Any traffic matching this route will be discarded by the edge routers.
NEW QUESTION # 66
What is the correct order of packet flow through configurable components in the Junos OS CoS features?
- A. Behavior Aggregate Classifier -> Input Policer -> Multifield Classifier -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Scheduler/Shaper/RED -> Rewrite Marker
- B. Multifield Classifier -> Behavior Aggregate Classifier -> Input Policer -> Forwarding Policy Options -> Fabric Scheduler -> Output Policer -> Rewrite Marker -> Scheduler/Shaper/RED
- C. Behavior Aggregate Classifier -> Multifield Classifier -> Input Policer -> 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: A
Explanation:
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 # 67
In IS-IS, which two statements are correct about the designated intermediate system (DIS) on a multi-access network segment? (Choose two)
- A. On the multi-access network, each router only forms an adjacency to the DIS.
- B. A router with a priority of 1 wins the DIS election over a router with a priority of 10.
- C. A router with a priority of 10 wins the DIS election over a router with a priority of 1.
- D. On the multi-access network, each router forms an adjacency to every other router on the segment
Answer: A,C
Explanation:
In IS-IS, a designated intermediate system (DIS) is a router that is elected on a multi-access network segment (such as Ethernet) to perform some functions on behalf of other routers on the same segment. A DIS is responsible for sending network link-state advertisements (LSPs), which describe all the routers attached to the network. These LSPs are flooded throughout a single area. A DIS also generates pseudonode LSPs, which represent the multi-access network as a single node in the link-state database. A DIS election is based on the priority value configured on each router's interface connected to the multi-access network. The priority value ranges from 0 to 127, with higher values indicating higher priority. The router with the highest priority becomes the DIS for the area (Level 1, Level 2, or both). If routers have the same priority, then the router with the highest MAC address is elected as the DIS. By default, routers have a priority value of 64. On a multi-access network, each router only forms an adjacency to the DIS, not to every other router on the segment. This reduces the amount of hello packets and LSP
NEW QUESTION # 68
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.)
- A. R1 will prepend AS 65531 when advertising 10 0.0 0/16 to R2.
- B. R2 will advertise 10.0.0.0/16 to R3 with 192.168.1 1 as the next hop
- C. R2 will advertise 10.0.0.0/16 to R4 with 172.16.1.1 as the next hop
- D. R1 will advertise 10.0.0.0/16 to R2 with 192 168 1 1 as the next hop.
- E. R4 will advertise 10 0.0 0/16 to R6 with 172.16 1 1 as the next hop
Answer: A,B,C
NEW QUESTION # 69
Which two statements about IS-IS are correct? (Choose two.)
- A. PSNPs are flooded periodically.
- B. CSNPs contain only descriptions of LSPs.
- C. CSNPs are flooded periodically
- D. PSNPs contain only descriptions of LSPs.
Answer: C,D
Explanation:
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-p
4:
https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/concept/routing-policy-is-is-c
NEW QUESTION # 70
You are configuring anycast RP for load balancing and redundancy in your PIM-SM domain. You want to share active sources between RPs.
In this scenario, what are two solutions that will accomplish this task? (Choose two.)
- A. Configure MSDP on each RP router.
- B. Configure anycast PIM with the rp-set statement on each source DR router.
- C. Configure MSDP on each source DR router.
- D. Configure anycast PIM with the rp-set statement on each RP router.
Answer: A,D
NEW QUESTION # 71 
Click the Exhibit button.
You have an EVI implemented between PE-1, PE-2, and PE-3 to allow communication between CE-1 and CE-2. CE-2 receives unicast traffic from CE-1 on both links to PE-2 and PE-3. When CE-1 sends broadcast traffic, CE-2 receives it on only one of the multihomed links.
Referring to the exhibit, which EVPN route type enables this behavior?
- A. Type 3
- B. Type 2
- C. Type 1
- D. Type 4
Answer: A
Explanation:
In the context of Ethernet VPN (EVPN) and the behavior described in the exhibit, it's essential to understand the different EVPN route types and their specific functionalities. Here, CE-2 is receiving unicast traffic on both of its multihomed links to PE-2 and PE-3, but broadcast traffic is received only on one of these links.
**Explanation of EVPN Route Types**:
1. **Type 1 (Ethernet Auto-Discovery Routes)**:
- These routes are used for auto-discovery of Ethernet segments and for advertising VLAN membership.
- They do not directly influence the behavior described in the question.
2. **Type 2 (MAC/IP Advertisement Routes)**:
- These routes are used to advertise MAC addresses and IP-to-MAC bindings within the EVPN.
- They handle unicast traffic forwarding and are crucial for populating the MAC address tables on the PE devices.
- While important, they do not explain the selective broadcast behavior.
3. **Type 3 (Inclusive Multicast Ethernet Tag Routes)**:
- These routes are used to build multicast distribution trees for delivering broadcast, unknown unicast, and multicast (BUM) traffic.
- They ensure that BUM traffic is sent only once per Ethernet segment, preventing duplicate frames from being sent to multihomed CEs.
- This aligns with the behavior described where CE-2 receives broadcast traffic on only one link to prevent duplication.
4. **Type 4 (Ethernet Segment Routes)**:
- These routes are used to advertise the presence of an Ethernet segment and are crucial for Designated Forwarder (DF) election processes in multihoming scenarios.
- While relevant to multihoming, they are not directly responsible for the selective broadcast behavior.
**Conclusion**:
The behavior described, where CE-2 receives broadcast traffic on only one of its multihomed links, is controlled by Type 3 routes. These routes are specifically designed to handle inclusive multicast and broadcast traffic efficiently in EVPN environments, ensuring that such traffic is not duplicated across multiple links to the same CE.
**References**:
- Juniper Networks EVPN Documentation: [EVPN
Overview](https://www.juniper.net/documentation/en_US/junos/topics/concept/evpn-overview.html)
- RFC 7432, BGP MPLS-Based Ethernet VPN: [RFC 7432](https://tools.ietf.org/html/rfc7432) provides detailed descriptions of EVPN route types and their functions.
- Junos OS EVPN Configuration Guide: [Junos OS EVPN Configuration
Guide](https://www.juniper.net/documentation/en_US/junos/topics/topic-map/evpn.html)
NEW QUESTION # 72 
Click the Exhibit button.
PE-1 and PE-2 are configured with LDP-signaled pseudowires to provide connectivity between CE-1 and CE-2. You notice no connectivity exists between CE-1 and CE-2.
Referring to the exhibit, which two statements describe potential causes for this fault? (Choose two.)
- A. There is no LSP configured from PE-1 to PE-2.
- B. There is no LSP configured from PE-2 to PE-1.
- C. The VC IDs are mismatched.
- D. Interface ge-0/0/0 on PE-1 is down.
Answer: A,C
Explanation:
In the provided exhibit, PE-1 and PE-2 are configured with LDP-signaled pseudowires to provide Layer 2 connectivity between CE-1 and CE-2. The issue is that there is no connectivity between CE-1 and CE-2. Let's analyze the potential causes for this fault.
1. **LDP-Signaled Pseudowire (L2 Circuit) Configuration**:
- Pseudowires in MPLS networks use LDP (Label Distribution Protocol) to signal the virtual circuit (VC) labels between PE routers.
- For successful connectivity, the VC ID (Virtual Circuit Identifier) and LSPs (Label Switched Paths) between the PE routers must be correctly configured and operational.
2. **Analysis of the Exhibit**:
- The output shows the status of the L2 circuit connection on PE-1.
- The status (St) for the interface is `rmt Dn`, which indicates that the remote site (PE-2) is down or unreachable.
3. **Potential Causes**:
- **A. The VC IDs are mismatched**:
- Correct. If the VC IDs configured on PE-1 and PE-2 do not match, the L2 circuit cannot be established.
Mismatched VC IDs prevent the pseudowire from forming correctly.
- **B. There is no LSP configured from PE-1 to PE-2**:
- Correct. LSPs are required for MPLS forwarding. If there is no LSP from PE-1 to PE-2, the LDP session cannot establish a path for the pseudowire. This results in the pseudowire being down.
- **C. Interface ge-0/0/0 on PE-1 is down**:
- Incorrect. The interface status is shown as `Up`, meaning the physical interface is operational.
- **D. There is no LSP configured from PE-2 to PE-1**:
- While this might seem like a potential issue, the specific problem of the remote site being down (`rmt Dn`) typically relates more directly to the forward path from PE-1 to PE-2 (i.e., no LSP from PE-1 to PE-2). Hence, the more accurate immediate cause is covered in Option B.
**Conclusion**:
Given the analysis, the correct statements describing potential causes for the fault are:
**A. The VC IDs are mismatched.**
**B. There is no LSP configured from PE-1 to PE-2.**
**References**:
- Juniper Networks Documentation on L2 Circuits: [Configuring Layer 2
Circuits](https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/layer-2-circuits-configur
- MPLS Configuration Guide: [Juniper MPLS
Configuration](https://www.juniper.net/documentation/en_US/junos/topics/topic-map/mpls-overview.html)
NEW QUESTION # 73
Exhibit
Referring to the exhibit, which statement is true?
- A. The 10.101.1.0/24 route will only be shared if BGP is configured in the routing instance
- B. The 10.101.1.0/24 route will be shared if the auto-export parameter is configured
- C. The 10.101.1 0/24 route will be shared if there are other VRFs that use the same route target community
- D. The 10.101.1.0/24 route will be shared if the vrf-table-label parameter is configured.
Answer: B
Explanation:
The auto-export parameter is a routing option that allows a routing instance to share routes with other routing instances or the master routing table. The auto-export parameter automatically exports routes from one routing instance to another based on the route target communities attached to the routes. In this scenario, the
10.101.1.0/24 route will be shared if the auto-export parameter is configured under [edit routing-options] hierarchy level.
NEW QUESTION # 74
You are using a Layer 3 VPN to connect two customer sites. The VPN routes for the customer networks appear as hidden in the bgp. 13vpn. o routing table on the PE routers.
What is causing this problem?
- A. There is not an established MPLS LSP between the two PE routers.
- B. There is a routing loop in the service provider backbone.
- C. The routes use overlapping IP addresses.
- D. Route targets are not configured.
Answer: A
Explanation:
For a Layer 3 VPN to function correctly, an MPLS Label Switched Path (LSP) must be established between the Provider Edge (PE) routers. The MPLS LSP is necessary for the transport of VPN traffic across the service provider's backbone network. If the MPLS LSP is not established, the PE routers cannot forward the VPN traffic properly, causing the routes to be hidden in the BGP routing table.
Here's a breakdown of why the other options are less likely:
A: The routes use overlapping IP addresses.
* Overlapping IP addresses might cause issues with route advertisement and selection, but they would not typically cause routes to be hidden in the bgp.l3vpn.0 table.
C: There is a routing loop in the service provider backbone.
* While routing loops are problematic, they would not specifically cause the routes to be hidden in the bgp.l3vpn.0 table. Routing loops would more likely result in dropped packets or increased latency.
D: Route targets are not configured.
* Incorrect or missing route target configuration would prevent routes from being imported into the correct VRF, but it would not usually result in the routes being hidden. Instead, they would simply not appear in the relevant VRF.
Thus, the absence of an established MPLS LSP is the most plausible cause for the routes being hidden.
NEW QUESTION # 75
Your network is receiving the 203.0.113.0/24 network using EBGP from AS 64500 and AS 64501.
Both of these advertisements have identical local-preference values, AS-path lengths, and BGP origin codes. You want to influence the way your AS sends traffic to the 203.0.113.0/24 network.
In this scenario, which attribute would you consider next when selecting the best path?
- A. peer IP address
- B. IGP metric
- C. MED value
- D. router ID
Answer: D
Explanation:
By default, the MED attribute is only compared for routes received from the same neighbouring AS.
The next feasible tiebreaker in the BGP route selection algorithm would be Router ID.
NEW QUESTION # 76
......
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