Juniper JN0-280 Online Practice Questions and Exam Preparation

Juniper JN0-280 Online Questions & Answers

• Question 41:

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

  A. IBGP peers do not advertise routes learned from IBGP peers to other IBGP peers.
  B. EBGP uses the AS path to avoid loops.
  C. IBGP sessions are typically established between physical router interfaces.
  D. EBGP sessions are typically established between router loopback interfaces.
  A. IBGP peers do not advertise routes learned from IBGP peers to other IBGP peers.
  B. EBGP uses the AS path to avoid loops.

• Question 42:

  What are two consequences of having all network devices in a single collision domain? (Choose two.)

  A. The amount of network resource consumption does not change.
  B. The chance of packet collision is decreased.
  C. The chance of packet collision is increased.
  D. The amount of network resource consumption is increased.
  C. The chance of packet collision is increased.
  D. The amount of network resource consumption is increased.

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  Explanation/Reference:

  A collision domain is a network segment where data packets can "collide" with one another when being sent on the same network medium.

  Step-by-Step Breakdown:

  Increased Collision Probability:If all devices are in a single collision domain , the likelihood of packet collisions increases as more devices attempt to send packets simultaneously, leading to network inefficiencies. Increased Resource

  Consumption:More collisions result inincreased network resource consumption as devices need to retransmit packets, causing higher utilization of bandwidth and slowing down network performance.

  Juniper Reference:

  Collision Domains: Proper network segmentation using switches reduces collision domains, thereby improving network performance and reducing packet collisions.

• Question 43:

  Referring to the exhibit, how many milliseconds will pass before the BGP neighbor is considered dead?

  

  A. 1000ms
  B. 9000ms
  C. 2000ms
  D. 3000ms
  D. 3000ms

• Question 44:

  Fill in the blank: In BGP, a route received from an ___________ peer will not be advertised to another ___________ peer by default.

  A. IBGP, IBGP
  B. EBGP, EBGP
  C. EBGP, IBGP
  D. Static, Dynamic
  A. IBGP, IBGP

• Question 45:

  A switch receives a frame with a MAC address of FF-FF-FF-FF-FF-FF. Which action will the switch take on this frame?

  A. It will flood it out of all interfaces, except for the ingress interface.
  B. It will flood it out of all interfaces, except for the directly connected VLAN.
  C. It will flood it out of all interfaces, except for the next-hop interface.
  D. It will flood it out of all interfaces.
  A. It will flood it out of all interfaces, except for the ingress interface.

  ---

  Explanation/Reference:

  A MAC address of FF-FF-FF-FF-FF-FF is the Ethernet broadcast address . When a switch receives a frame with this destination MAC address, it is required to forward the frame to all interfaces except the one it was received on.

  Step-by-Step Breakdown:

  Broadcast Frame Handling:When a frame with the broadcast MAC address is received, the switch will flood it out of all active ports that belong to the same VLAN as the incoming frame. The broadcast frame is not sent back out of the ingress

  interface (the interface where the frame was originally received).

  Purpose of Flooding:Broadcasting is used to ensure that the frame reaches all devices within the broadcast domain (all devices within the same VLAN), which may not have a specific entry for the MAC address in their MAC address table.

  Juniper Reference:

  Layer 2 Frame Forwarding: Juniper switches flood broadcast frames to all ports in the same VLAN, except the port the frame was received on.

• Question 46:

  A generated route is configured under which hierarchy?

  A. [edit policy-options]
  B. [edit routing-instance]
  C. [edit routing-options]
  D. [edit protocols]
  C. [edit routing-options]

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  Explanation/Reference:

  A generated route in Junos OS is configured under the [edit routing-options] hierarchy.

  Step-by-Step Breakdown:

  Generated Routes:A generated route is created based on the presence of more specific routes in the routing table. It acts as a summary route and is generated when any of its contributing routes are active. This is commonly used to create

  aggregate routes in OSPF, BGP, or other protocols.

  Configuration Hierarchy:The configuration for generated routes is placed under[edit routing-options] , where other static and routing policies are also defined.

  Command Example:

  set routing-options generate route 10.10.0.0/16

  Juniper Reference:

  Routing Options: Juniper routers use the routing-options hierarchy to configure generated routes and other static routing behaviors.

• Question 47:

  What is the default route preference for a static route on a Junos device?

  A. 130
  B. 15
  C. 10 D. 5
  D

• Question 48:

  Which of the following are true about Layer 2 and Layer 3 strategies in data center architectures?

  A. Layer 2 strategies are typically used for creating large, flat networks.
  B. Layer 3 strategies cannot be used in conjunction with Layer 2 environments.
  C. Layer 3 strategies help in reducing broadcast domains.
  D. Layer 2 strategies are primarily used for inter-data center connectivity.
  A. Layer 2 strategies are typically used for creating large, flat networks.
  C. Layer 3 strategies help in reducing broadcast domains.

• Question 49:

  Which statement is correct about IBGP?

  A. It requires a physical full mesh.
  B. It requires a logical full mesh.
  C. It ensures that the local and remote peers use different AS numbers.
  D. It ensures that duplicate AS numbers are not present in the AS path.
  B. It requires a logical full mesh.

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  Explanation/Reference:

  In IBGP (Internal Border Gateway Protocol) , all routers within the same AS (Autonomous System) must have a logical full-mesh topology. This means that every IBGP router must be able to communicate with every other IBGP router directly

  or indirectly to ensure proper route propagation.

  Step-by-Step Breakdown:

  Logical Full Mesh:

  In an IBGP setup, routers do not re-advertise routes learned from one IBGP peer to another IBGP peer. This rule is in place to prevent routing loops within the AS. To ensure full route propagation, a logical full mesh is required, meaning every

  IBGP router must peer with every other IBGP router in the AS. This can be done either directly or via route reflection or confederation. Physical Full Mesh Not Required:The physical topology does not need to be a full mesh, but the BGP

  peering relationships must form a logical full mesh. Techniques like route reflectors or BGP confederations can reduce the need for manual full-mesh peering.

  Juniper Reference:

  IBGP Configuration: IBGP logical full mesh requirements can be simplified using route reflectors to avoid the complexity of manually configuring many IBGP peers.

• Question 50:

  What are the different OSPF area types? (Choose two)

  A. Stub Area
  B. Not-So-Stubby Area (NSSA)
  C. Default-Free Zone
  D. Virtual Link Area
  A. Stub Area
  B. Not-So-Stubby Area (NSSA)