Juniper JN0-280 Online Practice Questions and Exam Preparation

Juniper JN0-280 Online Questions & Answers

• Question 71:

  Referring to the exhibit, what needs to be done to make this a valid IP fabric?

  

  A. Remove the connection between the leaf nodes
  B. Remove one of the redundant links between a leaf node and a spine node
  C. Add two connections between the spine nodes
  D. Add a connection between the spine nodes
  A. Remove the connection between the leaf nodes

• Question 72:

  What are two device roles in a five-member Virtual Chassis? (Choose two.)

  A. PFE
  B. Control-board
  C. Line card
  D. Routing-engine
  C. Line card
  D. Routing-engine

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  Explanation/Reference:

  In a Virtual Chassis (VC) configuration, multiple Juniper switches are interconnected to form a single logical device. Each member switch in the Virtual Chassis plays a specific role.

  Step-by-Step Breakdown:

  Line Card Role:

  Member switches acting as line cards provide additional ports for traffic forwarding but do not perform control or routing functions. These switches depend on the routing engine to handle control-plane tasks.

  Routing Engine Role:

  A switch in the routing-engine role is responsible for control-plane operations such as routing protocol management and control of the Virtual Chassis.

  Virtual Chassis Roles:

  Master Routing Engine: Handles control-plane functions and manages the entire Virtual Chassis.

  Backup Routing Engine: Takes over if the master fails.

  Line Card: Provides additional ports and handles data-plane operations.

  Juniper Reference:

  Virtual Chassis: In a five-member Virtual Chassis, multiple switches act as line cards , while one or more switches are designated as the routing engines (master and backup).

• Question 73:

  How can OSPF be configured to prefer one route over another?

  A. By setting a higher cost on the preferred route.
  B. By configuring route redistribution.
  C. By adjusting interface bandwidth.
  D. By setting a lower cost on the preferred route.
  D. By setting a lower cost on the preferred route.

• Question 74:

  Referring to the exhibit,

  

  which behavior does this configuration enable on the ge-0/0/1.0 interface?

  A. This configuration enables a MAC address learned on the interface to be persistently retained in the Ethernet-switching table, even after a reboot.
  B. This configuration enables the device to place a MAC address that persistently causes network errors into a special protected VLAN.
  C. This configuration enables the device to shut down the interface when a particular MAC address persistently sends broadcast traffic.
  D. This configuration enables the interface to learn and remember MAC addresses, until the device is rebooted.
  A. This configuration enables a MAC address learned on the interface to be persistently retained in the Ethernet-switching table, even after a reboot.

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  Explanation/Reference:

  The configuration in the exhibit shows the persistent-learning feature enabled on interface ge-0/0/1.0 .

  Step-by-Step Breakdown:

  Persistent Learning:

  Persistent-learningensures that the MAC addresses learned on the interface are retained in the Ethernet-switching table , even after a device reboot. This prevents the need to re-learn MAC addresses after the device restarts, improving

  stability and reducing downtime.

  Use Case:

  This feature is particularly useful in environments where the re-learning of MAC addresses could cause temporary disruptions or delays in communication, such as in critical Layer 2 network segments.

  Command Example:

  set switch-options interface ge-0/0/1.0 persistent-learning

  Juniper Reference:

  Persistent MAC Learning: In Junos, enabling persistent-learning ensures that learned MAC addresses are not lost during reboots, contributing to smoother network operations in environments where stability is crucial.

• Question 75:

  In a Spine/Leaf IP-Fabric architecture, what is the primary role of the leaf switches?

  A. To provide direct connectivity to servers.
  B. To interconnect different data centers.
  C. To perform deep packet inspection.
  D. To manage the overall data center network.
  A. To provide direct connectivity to servers.

• Question 76:

  What is the purpose of using route reflectors in BGP?

  A. To encrypt BGP messages
  B. To reduce the number of required IBGP sessions in a network
  C. To increase the speed of BGP convergence
  D. To automatically select the best route
  B. To reduce the number of required IBGP sessions in a network

• Question 77:

  What is the function of the 'Weight' attribute in BGP, and where is it used in the route selection process?

  A. It is used to prioritize routes received from different EBGP peers and is considered before the AS_PATH attribute.
  B. It determines the stability of a route and is checked after the Local Preference attribute.
  C. It is a Cisco-specific attribute used to prefer paths from one BGP speaker over another, evaluated before the Local Preference.
  D. It is used to balance load among multiple links and is considered after the MED attribute.
  C. It is a Cisco-specific attribute used to prefer paths from one BGP speaker over another, evaluated before the Local Preference.

• Question 78:

  Referring to the exhibit, how many broadcast domains are present in the topology?

  

  B. 1
  C. 2
  D. 3s
  B. 1

• Question 79:

  When configuring BGP, which command is commonly used to define a BGP neighbor?

  A. bgp set neighbor
  B. neighbor remote-as
  C. set bgp peer
  D. add bgp connection
  B. neighbor remote-as

• Question 80:

  Which statement is correct about member interfaces when creating a LAG?

  A. The interface's MTU settings must match on all member interfaces.
  B. The interface's duplex settings and link speed must be the same on all member interfaces.
  C. Member interfaces must all be allocated on the same chassis when using a Virtual Chassis.
  D. Member interfaces must all be allocated on the same PFE.
  B. The interface's duplex settings and link speed must be the same on all member interfaces.

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  Explanation/Reference:

  When creating a LAG (Link Aggregation Group) in Junos, the duplex settings and link speed must be the same across all member interfaces.

  Step-by-Step Breakdown:

  LAG Overview:A LAG combines multiple physical interfaces into a single logical interface to increase bandwidth and provide redundancy. All member links must act as a single cohesive unit.

  Interface Requirements:

  Duplex: All member interfaces must operate in the same duplex mode (either full-duplex or half- duplex). Mismatched duplex settings can cause performance issues, packet drops, or interface errors. Link Speed: All interfaces in the LAG must

  have the same link speed (e.g., all interfaces must be 1 Gbps or 10 Gbps). Mismatched speeds would prevent the interfaces from functioning correctly within the LAG.

  Configuration and Validation: Ensure that all member interfaces have identical settings before adding them to the LAG. These settings can be checked using the show interfaces command, and the LAG can be configured using:

  set interfaces ae0 aggregated-ether-options link-speed 10g

  set interfaces ge-0/0/1 ether-options 802.3ad ae0

  Juniper Reference:

  LAG Configuration: Duplex and link speed must be consistent across member interfaces to ensure proper LAG operation in Juniper devices.