Juniper JN0-351 Enterprise Routing and Switching, Specialist (JNCIS-ENT) Online Training

Question #1

Exhibit.

Which router will become the OSPF BDR if all routers are powered on at the same time?

A . R4
B . R1
C . R3
D . R2

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Question #2

Exhibit.

What is the management IP address of the device shown in the exhibit?

A . 10.210.20.233
B . 172.23.12.100
C . 128.0.0.1
D . 172.23.11.10

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Question #3

Which three protocols support BFD? (Choose three.)

A . RSTP
B . BGP
C . OSPF
D . LACP
E . FTP

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Correct Answer: BCD
BCD

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.

Explanation:

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]

Question #4

Exhibit.

The ispi _ inet. 0 route table has currently no routes in it.

What will happen when you commit the configuration shown on the exhibit?

A . The inet. 0 route table will be completely overwritten by the ispi . inet. 0 route table.
B . The inet. 0 route table will be imported into the ispi . inet. 0 route table.
C . The ISPI . inet. 0 route table will be completely overwritten by the inet. o route table.
D . The ISPI . inet. 0 route table will be imported into the inet. 0 route table.

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Question #5

Which statement is correct about graceful Routing Engine switchover (GRES)?

A . The PFE restarts and the kernel and interface information is lost.
B . GRES has a helper mode and a restarting mode.
C . When combined with NSR, routing is preserved and the new master RE does not restart rpd.
D . With no other high availability features enabled, routing is preserved and the new master RE does not restart rpd.

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Question #6

Which statement is correct about controlling the routes installed by a RIB group?

A . An import policy is applied to the RIB group.
B . Only routes in the last table are installed.
C . A firewall filter must be configured to install routes in the RIB groups.
D . An export policy is applied to the RIB group.

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Question #7

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 . Create static routes on the switches using the local vMX router’s loopback interface for the next hop.
B . Configure and apply a routing policy that redistributes the Dallas and Denver subnets using Type 5 LSAs.
C . Configure and apply a routing policy that redistributes the connected Dallas and Denver subnets.
D . Enable the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets.

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Question #8

Exhibit.

You want to verify prefix information being sent from 10.36.1.4.

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

A . The routes displayed have traversed one or more autonomous systems.
B . The output shows routes that were received prior to the application of any BGP import policies.
C . The output shows routes that are active and rejected by an import policy.
D . The routes displayed are being learned from an I BGP peer.

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Question #9

What is the default keepalive time for BGP?

A . 10 seconds
B . 60 seconds
C . 30 seconds
D . 90 seconds

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Question #10

Which two statements are correct about tunnels? (Choose two.)

A . BFD cannot be used to monitor tunnels.
B . Tunnel endpoints must have a valid route to the remote tunnel endpoint.
C . IP-IP tunnels are stateful.
D . Tunnels add additional overhead to packet size.

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Correct Answer: BD
BD

Explanation:

A tunnel is a connection between two computer networks, in which data is sent from one network to another through an encrypted link. Tunnels are commonly used to secure data communications between two networks or to connect two networks that use different protocols.

Option B is correct, because tunnel endpoints must have a valid route to the remote tunnel endpoint. A tunnel endpoint is the device that initiates or terminates a tunnel connection. For a tunnel to be established, both endpoints must be able to reach each other over the underlying network. This means that they must have a valid route to the IP address of the remote endpoint1.

Option D is correct, because tunnels add additional overhead to packet size. Tunnels work by encapsulating packets: wrapping packets inside of other packets. This means that the original packet becomes the payload of the surrounding packet, and the surrounding packet has its own header and trailer. The header and trailer of the surrounding packet add extra bytes to the packet size, which is called overhead. Overhead can reduce the efficiency and performance of a network, as it consumes more bandwidth and processing power2.

Option A is incorrect, because BFD can be used to monitor tunnels. 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. BFD can also be used to monitor the connectivity of tunnels, such as GRE, IPsec, or MPLS.

Option C is incorrect, because IP-IP tunnels are stateless. 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 are stateless, which means that they do not keep track of the state or status of the tunnel connection. Stateless tunnels do not require any signaling or negotiation between the endpoints, but they also do not provide any error detection or recovery mechanisms.

Reference: 1: What is Tunneling? | Tunneling in Networking 2: What Is Tunnel In Networking, Its Types, And Its

Benefits? : [Configuring Bidirectional Forwarding Detection] : [IP-IP Tunneling]

Juniper JN0-351 Enterprise Routing and Switching, Specialist (JNCIS-ENT) Online Training