JN0-351 Exam Dumps, JN0-351 Practice Test Questions
PDF (New 2024) Actual Juniper JN0-351 Exam Questions
Juniper JN0-351 Exam Syllabus Topics:
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NEW QUESTION # 30
Exhibit
Your BGP neighbors, one in the USA and one in France, are not establishing a connection with each other.
Referring to the exhibit, which statement is correct?
- A. The BFD liveness is set too high.
- B. The BFD liveness must be configured on the BGP group.
- C. The BFD liveness is set too low.
- D. The BFD liveness must be configured on the BGP neighbor.
Answer: D
Explanation:
Explanation
The exhibit shows the configuration of BFD liveness detection for BGP at the global level, which applies to all BGP neighbors by default1. However, this configuration does not specify the session mode, which determines whether BFD uses single-hop or multihop mode to communicate with a neighbor2.
For single-hop BGP neighbors, which are directly connected on the same subnet, the session mode can be either automatic or single-hop. For multihop BGPneighbors, which are not directly connected and require multiple hops to reach, the session mode must be multihop2.
Since your BGP neighbors are in different countries, they are likely to be multihop neighbors. Therefore, you need to configure the session mode as multihop for each neighbor individually at the [edit protocols bgp group group-name neighbor address bfd-liveness-detection] hierarchy level2. For example:
protocols { bgp { group usa { neighbor 192.0.2.1 { bfd-liveness-detection { session-mode multihop; } } } group france { neighbor 198.51.100.1 { bfd-liveness-detection { session-mode multihop; } } } } } If you do not configure the session mode for multihop neighbors, BFD will use the default mode of automatic, which will try to use single-hop mode and fail to establish a BFD session with the remote neighbor2. This will prevent BGP from using BFD to detect liveliness and failover.
Therefore, the answer B is correct, as you need to configure the BFD liveness detection on the BGP neighbor level with the appropriate session mode for multihop neighbors.
NEW QUESTION # 31
What are two reasons for creating multiple areas in OSPF? (Choose two.)
- A. to reduce the convergence time
- B. to reduce LSA flooding across the network
- C. to increase the size of the LSDB
- D. to increase the number of adjacencies in the backbone
Answer: A,B
Explanation:
Explanation
Option A is correct. Creating multiple areas in OSPF can help to reduce the convergence time . This is because changes in one area do not affect other areas, so fewer routers need to run the SPF algorithm in response to a change.
Option D is correct. Creating multiple areas in OSPF can help to reduce Link State Advertisement (LSA) flooding across the network. This is because LSAs are not flooded out of their area of origin.
NEW QUESTION # 32
Which statement is correct about IP-IP tunnels?
- A. IP-IP tunnels only support encapsulating IP traffic.
- B. There are 24 bytes of overhead with IP-IP encapsulation.
- C. IP-IP tunnels only support encapsulating non-IP traffic.
- D. The TTL in the inner packet is decremented during transit to the tunnel endpoint.
Answer: A
Explanation:
Explanation
IP-IP tunnels are a type of tunnels that use IP as both the encapsulating and encapsulated protocol. IP-IP tunnels are simple and easy to configure, but they do not provide any security or authentication features. IP-IP tunnels only support encapsulating IP traffic, which means that the payload of the inner packet must be an IP packet. IP-IP tunnels cannot encapsulate non-IP traffic, such as Ethernet frames or MPLS labels1.
Option A is correct, because IP-IP tunnels only support encapsulating IP traffic. Option B is incorrect, because IP-IP tunnels only support encapsulating non-IP traffic. Option C is incorrect, because the TTL in the inner packet is not decremented during transit to the tunnel endpoint. The TTL in the outer packet is decremented by each router along the path, but the TTL in the inner packet is preserved until it reaches the tunnel endpoint2.
Option D is incorrect, because there are 20 bytes of overhead with IP-IP encapsulation. The overhead consists of the header of the outer packet, which has a fixed size of 20 bytes for IPv43.
References:
1: IP-IP Tunneling 2: What is tunneling? | Tunneling in networking 3: IPv4 - Header
NEW QUESTION # 33
Which two statements about redundant trunk groups on EX Series switches are correct? (Choose two.)
- A. Redundant trunk groups use spanning tree to provide loop-free redundant uplinks.
- B. Redundant trunk groups load balance traffic across two designated uplink interfaces.
- C. If the active link fails, then the secondary link automatically takes over.
- D. Layer 2 control traffic is permitted on the secondary link.
Answer: C,D
Explanation:
C is correct because Layer 2 control traffic is permitted on the secondary link of a redundant trunk group (RTG) on EX Series switches. Layer 2 control traffic includes protocols such as LLDP, LACP, and STP, which are used to exchange information and coordinate actions between switches1. According to the Juniper Networks documentation2, Layer 2 control traffic is allowed to pass through both the active and the secondary links of an RTG, but data traffic is only forwarded through the active link. This allows the switches to maintain their Layer 2 adjacencies and monitor the link status on both links.
D is correct because if the active link fails, then the secondary link automatically takes over in an RTG on EX Series switches. An RTG consists of two trunk links: an active or primary link, and a secondary or backup link2. The active link is used to forward data traffic, while the secondary link is in standby mode. If the active link fails or becomes unavailable, the secondary link immediately transitions to a forwarding state and takes over the data traffic without waiting for normal STP convergence2. This provides fast recovery and redundancy for the network.
NEW QUESTION # 34
You need to configure a LAG between your switches. In this scenario, which two statements are correct?
(Choose two.)
- A. Member links are not required to be contiguous ports.
- B. Member links are required to be contiguous ports.
- C. Duplex and speed settings are not required to match on both participating devices.
- D. Duplex and speed settings are required to match on both participating devices.
Answer: A,D
Explanation:
B is correct because duplex and speed settings are required to match on both participating devices. According to the Juniper Networks documentation1, all the interfaces in a LAG must have the same speed and be in full-duplex mode. This ensures that the LAG can operate as a single logical link without any performance or compatibility issues.
C is correct because member links are not required to be contiguous ports. According to the Juniper Networks documentation2, you can group any Ethernet interfaces on a switch into a LAG, regardless of their physical location or slot number. This provides flexibility and scalability for configuring LAGs on switches.
NEW QUESTION # 35
Which statement is correct about the storm control feature?
- A. The storm control feature is enabled in the factory-default configuration on EX Series switches.
- B. The storm control configuration only applies to traffic being sent between the forwarding and control plane.
- C. The storm control feature requires a special license on EX Series switches.
- D. The storm control feature is not supported on aggregate Ethernet interfaces.
Answer: A
Explanation:
Option A is correct. The storm control feature is enabled in the factory-default configuration on EX Series switches12. On EX2200, EX3200, EX3300, EX4200, and EX6200 switches, the factory default configuration enables storm control for broadcast and unknown unicast traffic on all switch interfaces2. On EX4300 switches, the factory default configuration enables storm control on all Layer 2 switch interfaces1.
Option B is incorrect. The storm control feature does not require a special license on EX Series switches34.
Option C is incorrect. There's no information available that suggests the storm control feature is not supported on aggregate Ethernet interfaces.
Option D is incorrect. The storm control configuration applies to traffic at the ingress of an interface5, not just between the forwarding and control plane.
NEW QUESTION # 36
Exhibit.
Why is this OSPF adjacency remaining in this state?
- A. A hello interval mismatch exists between the OSPF neighbors.
- B. A subnet mask mismatch exists between the OSPF neighbors.
- C. An MTU mismatch exists between the OSPF neighbors.
- D. An area ID mismatch exists between the OSPF neighbors
Answer: C
Explanation:
The exhibit shows the output of the command , which displays information about the OSPF neighbors on a router1.
The output shows that the OSPF neighbor with the address 172.26.1.1 and the interface ge-0/0/3.0 is in the Exstart state1.
The Exstart state is the fourth state in the OSPF neighbor formation process, after Down, Init, and
2-Way states2. In this state, the OSPF neighbors establish a master-slave relationship and exchange database description (DBD) packets, which contain summaries of their link-state databases2.
The most common reason for OSPF neighbors to be stuck in the Exstart state is an MTU mismatch between the interfaces3. MTU stands for maximum transmission unit, which is the largest size of a packet that can be transmitted on a network segment4. If the MTU values of two OSPF neighbors are different, theymay not be able to exchange DBD packets successfully, as some packets may be dropped or fragmented due to their size exceeding the MTU limit3.
To solve this problem, you need to ensure that the MTU values of both OSPF neighbors are the same or compatible. You can use the command show interfaces to display the MTU value of an interface5. You can also use the command ping with the do-not-fragment option to test the MTU size between two routers. You can change the MTU value of an interface by using the command set interfaces interface-name mtu mtu-value in configuration mode5.
NEW QUESTION # 37
Exhibit.
You have configured the four EX Series switches with RSTP, as shown in the exhibit. You discover that whenever a link between switches goes up or down, the switches take longer than expected for RSTP to converge, using the default settings.
In this scenario, which action would solve the delay in RSTP convergence?
- A. The force-version must be removed.
- B. The max-age must be increased to 20
- C. The hello-time must be increased.
- D. The bridge priority for EX-4 must be set at 4000.
Answer: A
Explanation:
The exhibit shows the configuration of RSTP on EX-4, which has the command force-version stp. This command forces the switch to use the legacy STP protocol instead of RSTP, even though the switch supports RSTP1. This means that EX-4 will not be able to take advantage of the faster convergence and enhanced features of RSTP, such as edge ports, link type, and proposal/agreement sequence2.
The other switches in the network are likely to be running RSTP, as it is the default protocol for EX Series switches3. Therefore, there will be a compatibility issue between EX-4 and the other switches, which will result in longer convergence times and suboptimal performance. The switch will also generate a warning message that says "Warning: STP version mismatch with neighbor" when it receives a BPDU from a RSTP neighbor1.
To solve this problem, the force-version command must be removed from EX-4, so that it can run RSTP natively and interoperate with the other switches in the network. This will enable faster convergence and better stability for the network topology. To remove the command, you can use the delete protocols rstp force-version command in configuration mode1.
NEW QUESTION # 38
You implemented the MAC address limit feature with the shutdown action on all interfaces on your switch.
In this scenario, which statement is correct when a violation occurs?
- A. By default, devices that are learned before the violation occurs are still allowed to send and receive traffic through the specific interface.
- B. By default, the interface will continue to send and receive traffic for all connected devices after a violation has occurred.
- C. By default, you must manually clear the violation for the interface to send and receive traffic again.
- D. By default, the violation will automatically be cleared after 300 seconds and the interface will resume sending and receiving traffic for all learned devices.
Answer: C
Explanation:
Explanation
When the MAC address limit feature with the shutdown action is implemented on a switch, if a violation occurs, the interface is disabled and a system log entry is generated1. If the switch has been configured with the port-error-disable statement, the disabled interface recovers automatically upon expiration of the specified disable timeout1. However, if the switch has not been configured for auto-recovery from port error disabled conditions, you must manually clearthe violation by running the clear ethernet-switching port-error command for the interface to send and receive traffic again1. This explanation is based on the Enterprise Routing and Switching Specialist (JNCIS-ENT) documents and learning resources available at Juniper Networks1.
NEW QUESTION # 39
What are two characteristics of RSTP alternate ports? (Choose two.)
- A. RSTP alternate ports are active ports used to forward frames toward the root bridge.
- B. RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch.
- C. RSTP alternate ports provide an alternate higher cost path to the root bridge.
- D. RSTP alternate ports provide an alternate lower cost path to the root bridge.
Answer: B,C
Explanation:
A is correct because RSTP alternate ports block traffic while receiving superior BPDUs from a neighboring switch. An alternate port is a backup port for a root port, which means it receives better BPDUs from another bridge than the current root port1. However, an alternate port does not forward any traffic, as it is in a discarding state2. It only listens to BPDUs and waits for the root port to fail. If the root port fails, the alternate port can immediately transition to a forwarding state and become the new root port1.
C is correct because RSTP alternate ports provide an alternate higher cost path to the root bridge. An alternate port is selected based on the same criteria as the root port, which are the lowest bridge ID, the lowest path cost, the lowest sender port ID, and the lowest receiver port ID3. However, an alternate port receives a higher cost BPDU than the root port, otherwise it would be the root port itself1. Therefore, an alternate port provides an alternate higher cost path to the root bridge than the root port.
NEW QUESTION # 40
Which two statements about redundant trunk groups on EX Series switches are correct? (Choose two.)
- A. Layer 2 control traffic is permitted on the secondary link
- B. Redundant trunk groups must be connected to the same aggregation switch.
- C. If the active link fails, then the secondary link automatically takes over.
- D. Redundant trunk groups load-balance traffic across two designated uplink interfaces.
Answer: B,C
Explanation:
Explanation
Redundant Trunk Groups (RTGs) on EX Series switches provide a simple solution for network recovery when a trunk port on a switch goes down1. They are configured on the access switch and contain two links: a primary or active link, and a secondary link1. Therefore, option B is correct because if the active link fails, the secondary link automatically starts forwarding data traffic without waiting for normal spanning-tree protocol convergence1.
Option D is also correct. In a typical enterprise network composed of distribution and access layers, RTGs are used where one Access switch is connected to two different uplink switches2. This implies that RTGs must be connected to the same aggregation switch2.
NEW QUESTION # 41
Which three protocols support BFD? (Choose three.)
- A. FTP
- B. BGP
- C. RSTP
- D. LACP
- E. OSPF
Answer: B,D,E
Explanation:
Explanation
BFD is a protocol that can be used to quickly detect failures in the forwarding path between two adjacent routers or switches. BFD can be integrated with various routing protocols and link aggregation protocols to provide faster convergence and fault recovery.
According to the Juniper Networks documentation, the following protocols support BFD on Junos OS devices1:
BGP: BFD can be used to monitor the connectivity between BGP peers and trigger a session reset if a failure is detected. BFD can be configured for both internal and external BGP sessions, as well as for IPv4 and IPv6 address families2.
OSPF: BFD can be used to monitor the connectivity between OSPF neighbors and trigger a state change if a failure is detected. BFD can be configured for both OSPFv2 and OSPFv3 protocols, as well as for point-to-point and broadcast network types3.
LACP: BFD can be used to monitor the connectivity between LACP members and trigger a link state change if a failure is detected. BFD can be configured for both active and passive LACP modes, as well as for static and dynamic LAGs4.
Other protocols that support BFD on Junos OS devices are:
IS-IS: BFD can be used to monitor the connectivity between IS-IS neighbors and trigger a state change if a failure is detected. BFD can be configured for both level 1 and level 2 IS-IS adjacencies, as well as for point-to-point and broadcast network types.
RIP: BFD can be used to monitor the connectivity between RIP neighbors and trigger a route update if a failure is detected. BFD can be configured for both RIP version 1 and version 2 protocols, as well as for IPv4 and IPv6 address families.
VRRP: BFD can be used to monitor the connectivity between VRRP routers and trigger a priority change if a failure is detected. BFD can be configured for both VRRP version 2 and version 3 protocols, as well as for IPv4 and IPv6 address families.
The protocols that do not support BFD on Junos OS devices are:
RSTP: RSTP is a spanning tree protocol that provides loop prevention and rapid convergence in layer 2 networks. RSTP does not use BFD to detect link failures, but relies on its own hello mechanism that sends BPDU packets every 2 seconds by default.
FTP: FTP is an application layer protocol that is used to transfer files between hosts over a TCP connection. FTP does not use BFD to detect connection failures, but relies on TCP's own retransmission and timeout mechanisms.
References:
1: [Configuring Bidirectional Forwarding Detection] 2: [Configuring Bidirectional Forwarding Detection for BGP] 3: [Configuring Bidirectional Forwarding Detection for OSPF] 4: [Configuring Bidirectional Forwarding Detection for Link Aggregation Control Protocol] : [Configuring Bidirectional Forwarding Detection for IS-IS] : [Configuring Bidirectional Forwarding Detection for RIP] : [Configuring Bidirectional Forwarding Detection for VRRP] : [Understanding Rapid Spanning Tree Protocol] : [Understanding FTP]
NEW QUESTION # 42
Which two mechanisms are part of building and maintaining a Layer 2 bridge table? (Choose two.)
- A. listening
- B. learning
- C. blocking
- D. flooding
Answer: B,D
Explanation:
Option B is correct. Flooding is a mechanism used in Layer 2 bridging where the switch sends incoming packets to all its ports except for the port where the packet originated1. This is done when the switch doesn't know the destination MAC address or when the packet is a broadcast or multicast1.
Option C is correct. Learning is another mechanism used in Layer 2 bridging where the switch learns the source MAC addresses of incoming packets and associates them with the port on which they were received23. This information is stored in a MAC address table, also known as a bridge table23.
Option A is incorrect. Blocking is a state in Spanning Tree Protocol (STP) used to prevent loops in a network2. It's not a mechanism used in building and maintaining a Layer 2 bridge table2.
Option D is incorrect. Listening is also a state in Spanning Tree Protocol (STP) where the switch listens for BPDUs to make sure no loops occur in the network before transitioning to the learning state2. It's not a mechanism used in building and maintaining a Layer 2 bridge table2.
NEW QUESTION # 43
You are configuring an IS-IS IGP network and do not see the IS-IS adjacencies established. In this scenario, what are two reasons for this problem? (Choose two.)
- A. MTU is not at least 1492 bytes.
- B. The lo0 interface is not included as an IS-IS interface.
- C. The Level 2 routers have mismatched areas.
- D. IP subnets are not a /30 address.
Answer: A,B
Explanation:
Explanation
Option A suggests that the MTU is not at least 1492 bytes. This is correct because IS-IS requires a minimum MTU of 1492 bytes to establish adjacencies1. If the MTU is less than this, IS-IS adjacencies will not be established1.
Option D suggests that the lo0 interface is not included as an IS-IS interface. This is also correct because the loopback interface (lo0) is typically used as the router ID in IS-IS1. If the loopback interface is not included in IS-IS, it could prevent IS-IS adjacencies from being established1.
Therefore, options A and D are correct.
NEW QUESTION # 44
Exhibit.
You are using OSPF to advertise the subnets that are used by the Denver and Dallas offices. The routers that are directly connected to the Dallas and Denver subnets are not advertising the connected subnets.
Referring to the exhibit, which two statements are correct? (Choose two.)
- A. Configure and apply a routing policy that redistributes the Dallas and Denver subnets using Type 5 LSAs.
- B. Enable the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets.
- C. Create static routes on the switches using the local vMX router's loopback interface for the next hop.
- D. Configure and apply a routing policy that redistributes the connected Dallas and Denver subnets.
Answer: B,D
Explanation:
Explanation
The routers that are directly connected to the Dallas and Denver subnets are not advertising the connected subnets. This can be resolved by redistributing the connected subnets into OSPF1.
Option C suggests to configure and apply a routing policy that redistributes the connected Dallas and Denver subnets. This is correct because redistribution allows routes from one routing protocol to be communicated to another, and in this case, it allows the connected subnets to be advertised through OSPF1.
Option D suggests enabling the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets. This is also correct because in OSPF, a passive interface is an interface that belongs to the OSPF router, but does not send OSPF Hello packets1. It's typically used on an interface that you don't want to use for OSPF adjacencies, but you still want to advertise its IP address1. Therefore, enabling passive interface can help in advertising the Dallas and Denver subnets.
NEW QUESTION # 45
Exhibit
Referring to the exhibit, which two configuration changes must you apply for packets to reach from R1 to R3 using IS-IS? (Choose two.)
- A. On R1, enable Level 1 on the ge-0/0/1 interface.
- B. On R1, disable Level 2 on the ge-0/0/1 interface.
- C. On R3 enable Level 1 on the ge-0/0/4 interface
- D. On R3 disable Level 2 on the ge-0/0/4 interface.
Answer: A,C
Explanation:
Explanation
A: On R1, enable Level 1 on the ge-0/0/1 interface. In IS-IS, both levels (Level 1 and Level 2) are enabled by default when you enable IS-IS on an interface1. Level 1 systems route within an area2. If the destination is outside an area, Level 1 systems route toward a Level 2 system2. Therefore, enabling Level 1 on the ge-0/0/1 interface on R1 would allow packets to reach from R1 to R3.
D: On R3 enable Level 1 on the ge-0/0/4 interface Similarly, enabling Level 1 on the ge-0/0/4 interface on R3 would allow packets to reach from R1 to R3.
These explanations are based on the IS-IS configuration documents and learning resources available at Juniper Networks1 and Cisco34.
NEW QUESTION # 46
After receiving a BGP route, which two conditions are verified by the receiving router to ensure that the received route is valid? (Choose two)
- A. The local preference is greater than 0.
- B. The AS-path length is greater than 0.
- C. The loops do not exist.
- D. The next hop is reachable.
Answer: C,D
Explanation:
B is correct because the loops do not exist is one of the conditions that are verified by the receiving router to ensure that the received BGP route is valid. A loop in BGP means that a route has been advertised by the same AS more than once, which can cause routing instability and inefficiency1. To prevent loops, BGP uses the AS-path attribute, which lists the AS numbers that a route has traversed from the origin to the destination2. The receiving router checks the AS-path attribute of the received route and discards it if it finds its own AS number in the list2. This way, BGP avoids accepting routes that contain loops.
C is correct because the next hop is reachable is one of the conditions that are verified by the receiving router to ensure that the received BGP route is valid. The next hop is the IP address of the next router that is used to forward packets to the destination network3. The receiving router checks the next hop attribute of the received route and verifies that it has a valid route to reach it3. If the next hop is not reachable, the received route is not usable and is rejected by the receiving router3. This way, BGP ensures that only feasible routes are accepted.
NEW QUESTION # 47
A new network requires multiple topology support. You decide to use IS-IS in this situation. Which three protocol topologies are supported in this scenario? (Choose three.)
- A. anycast
- B. IPv4
- C. IPv6
- D. IPsec
- E. multicast
Answer: B,C,E
Explanation:
Explanation
IS-IS (Intermediate System to Intermediate System) is a routing protocol that is designed to move information efficiently within a computer network12. It supports multiple protocol topologies, including IPv4, IPv6, and multicast12. Therefore, options C, E, and D are correct.
NEW QUESTION # 48
Exhibit
You have configured a GRE tunnel. To reduce the risk of dropping traffic, you have configured a keepalive OAM probe to monitor the state of the tunnel; however, traffic drops are still occurring.
Referring to the exhibit, what is the problem?
- A. The hold-time value must be two times the keepalive-time value
- B. LLDP needs to be removed from the gr-1/1/10.1 interface.
- C. The "event link-adjacency-loss" option must be set.
- D. For GRE tunnels, the OAM protocol requires that the BFD protocols also be used.
Answer: A
Explanation:
Explanation
A keepalive OAM probe is a mechanism that can be used to monitor the state of a GRE tunnel and detect any failures in the tunnel path. A keepalive OAM probe consists of sending periodic packets from one end of the tunnel to the other and expecting a reply. If no reply is received within a specified time, the tunnel is considered down and the line protocol of the tunnel interface is changed to down1.
To configure a keepalive OAM probe for a GRE tunnel, you need to specify two parameters: the keepalive-time and the hold-time. The keepalive-time is the interval between each keepalive packet sent by the local router. The hold-time is the maximum time that the local router waits for a reply from the remote router before declaring the tunnel down2.
According to the Juniper Networks documentation, the hold-time value must be two times the keepalive-time value for a GRE tunnel2. This is because the hold-time value must account for both the round-trip time of the keepalive packet and the processing time of the remote router. If the hold-time value is too small, it may cause false positives and unnecessary tunnel flaps.
In the exhibit, the configuration shows that the keepalive-time is set to 10 seconds and the hold-time is set to
15 seconds for the gr-1/1/10.1 interface. This means that the local router will send a keepalive packet every 10 seconds and will wait for 15 seconds for a reply from the remote router. However, this hold-time value is not two times the keepalive-time value, which violates the recommended configuration. This may cause traffic drops if the remote router takes longer than 15 seconds to reply.
Therefore, option D is correct, because the hold-time value must be two times the keepalive-time value for a GRE tunnel. Option A is incorrect, because BFD is not required for GRE tunnels; BFD is another protocol that can be used to monitor tunnels, but it is not compatible with GRE keepalives3. Option B is incorrect, because the "event link-adjacency-loss" option is not related to GRE tunnels; it is an option that can be used to trigger an action when a link goes down4. Option C is incorrect, because LLDP does not need to be removed from the gr-1/1/10.1 interface; LLDP is a protocol that can be used to discover neighboring devices and their capabilities, but it does not interfere with GRE tunnels5.
References:
1: Configuring Keepalive Time and Hold time for a GRE Tunnel Interface 2: keepalive | Junos OS | Juniper Networks 3: Configuring Bidirectional Forwarding Detection 4: event link-adjacency-loss | Junos OS | Juniper Networks 5: Understanding Link Layer Discovery Protocol
NEW QUESTION # 49
Exhibit
What does the * indicate in the output shown in the exhibit?
- A. The interface is active.
- B. All interfaces have elected a root bridge.
- C. The switch ports have a router attached.
- D. The interface is down.
Answer: A
Explanation:
The exhibit shows the output of the command show vlans brief, which displays brief information about VLANs and their associated interfaces1.
The output has four columns: Routing instance, VLAN name, Interfaces, and Tagging.
The * symbol indicates that the interface is active, meaning that it is up and forwarding traffic1. This can be verified by the command , which displays the status of the interfaces2.
NEW QUESTION # 50
What is the default MAC age-out timer on an EX Series switch?
- A. 300 seconds
- B. 300 minutes
- C. 30 seconds
- D. 30 minutes
Answer: A
Explanation:
Explanation
The default MAC age-out timer on an EX Series switch is 300 seconds12. The MAC age-out timer is the maximum time that an entry can remain in the MAC table before it "ages out," or is removed31. This configuration can influence efficiency of network resource use by affecting the amount of traffic that is flooded to all interfaces1. When traffic is received for MAC addresses no longer in the Ethernet routing table, the router floods the traffic to all interfaces1.
NEW QUESTION # 51
You are attempting to configure the initial two aggregated Ethernet interfaces on a router but there are no aggregated Ethernet interfaces available.
In this scenario, which configuration will enable these interfaces on this router?
- A.
- B.
- C.
- D.
Answer: D
Explanation:
Explanation
The correct answer to your question is
Option C shows the configuration of the statement, which defines the properties of the router chassis, such as the number of aggregated Ethernet interfaces, the number of FPCs, and the number of PICs1.
To enable aggregated Ethernet interfaces on a router, you need to specify the aggregated-devices statement under the chassis parameter to the desired number of interfaces2. For example, to enable two aggregated Ethernet interfaces, you can use the following configuration:
chassis { aggregated-devices { ethernet { device-count 2; } } }
Option C shows this configuration with the device-count set to 2, which will enable two aggregated Ethernet interfaces on the router. The other options do not show this configuration and will not enable any aggregated Ethernet interfaces on the router.
Therefore, option C is the correct answer to your question.
NEW QUESTION # 52
Exhibit
Referring to the exhibit, which statement is correct?
- A. The local device is the root bridge for this RSTP topology.
- B. The root bridge is using a bridge priority of 4k.
- C. The root bridge has not been elected for this RSTP topology.
- D. The local device is using a bridge priority of 4k.
Answer: A
Explanation:
Explanation
In a Rapid Spanning Tree Protocol (RSTP) topology, the root bridge is determined by the switch with the lowest bridge priority value12. If all switches have the same priority, then the root bridge is assigned to the switch whose MAC address's hex value is the lowest2. The default bridge priority value is 3276832. However, without the actual exhibit, it's difficult to definitively determine which device is the root bridge. But based on the options provided, if we assume that the local device has a lower bridge priority or a lower MAC address than other devices in the network, then it could be considered as the root bridge for this RSTP topology45.
NEW QUESTION # 53
You are an operator for a network running 1S-IS. Two routers are failing to form an adjacency. What are two reasons for this problem? (Choose two.)
- A. The family iso configuration is missing from the adjacency interface.
- B. There is a mismatched area ID between the L2 routers.
- C. There is no configured ISO address on any IS-IS interface.
- D. There are mismatched router IDs on the L2 routers.
Answer: A,C
Explanation:
Explanation
The two reasons for the failure to form an adjacency in a network running IS-IS could be:
B: There is no configured ISO address on any IS-IS interface. IS-IS requires each router interface to have an ISO address configured. Without this address, the routers cannot form an adjacency1.
D: The family iso configuration is missing from the adjacency interface. The 'family iso' configuration is essential for IS-IS to function correctly. If this configuration is missing from the adjacency interface, it could prevent the formation of an adjacency1.
These explanations are based on the Enterprise Routing and Switching Specialist (JNCIS-ENT) documents and learning resources available at Juniper Networks23.
NEW QUESTION # 54
You are asked to connect an IP phone and a user computer using the same interface on an EX Series switch.
The traffic from the computer does not use a VLAN tag, whereas the traffic from the IP phone uses a VLAN tag.
Which feature enables the interface to receive both types of traffic?
- A. MAC limiting
- B. native VLAN
- C. voice VLAN
- D. DHCP snooping
Answer: C
Explanation:
Explanation
The feature that enables an interface on an EX Series switch to receive both untagged traffic (from the computer) and tagged traffic (from the IP phone) is the voice VLAN12.
The voice VLAN feature in EX-series switches enables access ports to accept both data (untagged) and voice (tagged) traffic and separate that traffic into different VLANs12. This allows the switch to differentiate between voice and data traffic, ensuring that voice traffic can be treated with a higher priority12. Therefore, option D is correct.
NEW QUESTION # 55
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Updated Mar-2024 Pass JN0-351 Exam - Real Practice Test Questions: https://pass4lead.newpassleader.com/Juniper/JN0-351-exam-preparation-materials.html