Juniper Enterprise Routing and Switching, Specialist JN0-351 Exam Questions

Page: 1 / 14
Total 65 questions
Question 1

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?



Answer : B

The exhibit shows the configuration of RSTP on EX-4, which has the commandforce-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 thedelete protocols rstp force-versioncommand in configuration mode1.


Question 2

What is the default keepalive time for BGP?



Answer : B

The default keepalive time for BGP is60 seconds1.The keepalive time is the interval at which BGP sends keepalive messages to maintain the connection with its peer1.If the keepalive message is not received within the hold time, the connection is considered lost1.By default, the hold time is three times the keepalive time, which is180 seconds1.


Question 3

Which two types of tunnels are able to be created on all Junos devices? (Choose two.)



Answer : B, D

Junos devices support various types of tunnels for different purposes12.

Option B is correct.Generic Routing Encapsulation (GRE) is a tunneling protocol that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links over an Internet Protocol network1.Junos devices support GRE tunnels1.

Option D is correct.IPsec (Internet Protocol Security) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session1.Junos devices support IPsec tunnels1.

Option A is incorrect. Spanning Tree Protocol (STP) is not a type of tunnel.It's a network protocol designed to prevent loops in a bridged Ethernet local area network2.

Option C is incorrect.While Junos devices do support IP-IP (also known as IP tunneling), it's not supported on all Junos devices1.


Question 4

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.)



Answer : C, D

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.


Question 5

Exhibit

You are receiving the BGP route shown in the exhibit from four different upstream ISPs.

Referring to the exhibit, which ISP will be selected as the active path?



Answer : C

In BGP, the path selection process is based on a set of attributes1.The process starts by preferring the path with the highest weight, then the highest local preference, then the locally originated routes, and so on1.If all these attributes are the same, then it prefers the path with the shortest AS path1.

Referring to the exhibit, all four ISPs have the same weight, local preference, and origin1.However, ISP 4 has the shortest AS path1. Therefore, ISP 4 will be selected as the active path. So, option C is correct.


Question 6

You have two OSPF routers forming an adjacency. R1 has a priority of 32 and a router ID of 192.168.1.2. R2 has a priority of 64 and a router ID of 192.168.1.1. The routers were started at the same time and all other OSPF settings are the default settings.

Which statement is correct in this scenario?



Answer : D

In OSPF, the Designated Router (DR) and Backup Designated Router (BDR) are elected based on the priority of the routers1.The router with the highest priority becomes the DR, and the router with the second highest priority becomes the BDR1.If there is a tie in priority, then the router with the highest Router ID is chosen1.

In this scenario, R2 has a higher priority (64) than R1 (32), so R2 will become the DR1.Since R1 has the second highest priority, it will become the BDR1. Therefore, option D is correct.


Question 7

What is a purpose of using a spanning tree protocol?



Answer : B

A broadcast storm is a network condition where a large number of broadcast packets are sent and received by multiple devices, causing congestion and performance degradation1.A broadcast storm can occur when there are loops in the network topology, meaning that there are multiple paths between two devices2.

A spanning tree protocol is a network protocol that prevents loops from being formed when switches or bridges are interconnected via multiple paths.It does this by creating a logical tree structure that spans all the devices in the network, and disabling or blocking the links that are not part of the tree, leaving a single active path between any two devices3.

By eliminating loops, a spanning tree protocol also eliminates broadcast storms, as broadcast packets will not be forwarded endlessly along the looped paths.Instead, broadcast packets will be sent only along the tree structure, reaching each device once and avoiding congestion3.


Page:    1 / 14   
Total 65 questions