Juniper JN0-280 Online Practice Questions and Exam Preparation

Juniper JN0-280 Online Questions & Answers

• Question 61:

  Under which Junos hierarchy is a static route configured?

  A. system
  B. routing-instances
  C. routing-options
  D. protocols
  C. routing-options

• Question 62:

  What is the main purpose of Bidirectional Forwarding Detection (BFD)?

  A. to detect network path failures
  B. to determine if the forwarding routes are correct
  C. to detect the forwarding protocol
  D. to determine packet round-trip latency
  A. to detect network path failures

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  Explanation/Reference:

  Bidirectional Forwarding Detection (BFD)is a network protocol used to detect failures in the network path between two devices quickly.

  Step-by-Step Breakdown:

  Path Failure Detection:BFD provides a low-overhead mechanism for detecting failures in forwarding paths across Layer 3 networks. It is much faster than traditional routing protocol timers and can detect failures within milliseconds. BFD in

  Routing:BFD can be integrated with routing protocols like OSPF, BGP, or IS-IS to trigger a faster convergence when a network path goes down.

  Juniper Reference:

  BFD Configuration: Juniper devices use BFD to monitor network paths and ensure fast failure detection, enhancing network resilience.

• Question 63:

  What is the main advantage of using an Overlay Network in a data center?

  A. It simplifies physical network design by allowing multiple virtual topologies over it.
  B. It replaces the need for physical network infrastructure.
  C. It offers higher physical bandwidth capacity.
  D. It provides direct Internet access to applications.
  A. It simplifies physical network design by allowing multiple virtual topologies over it.

• Question 64:

  What is the primary purpose of using aggregate routes in a network?

  A. To dynamically adjust to network changes
  B. To summarize and reduce the number of routes in the routing table
  C. To filter unwanted traffic
  D. To statically define a route to a specific destination
  B. To summarize and reduce the number of routes in the routing table

• Question 65:

  In Ethernet switching, what is the primary function of a storm control policy?

  A. To prevent loops in the network.
  B. To restrict the rate of certain types of traffic.
  C. To filter MAC addresses.
  D. To segregate broadcast domains.
  B. To restrict the rate of certain types of traffic.

• Question 66:

  In OSPF, what is the function of the Link-State Database (LSDB)?

  A. To store OSPF routing tables.
  B. To maintain a list of OSPF neighbors.
  C. To keep the topology structure of the network.
  D. To log changes in network topology.
  C. To keep the topology structure of the network.

• Question 67:

  Which of the following are true regarding port modes in a VLAN setup? (Choose two)

  A. An access port can carry traffic for multiple VLANs.
  B. A trunk port can carry traffic for multiple VLANs.
  C. An access port carries traffic only for a single VLA
  D. A trunk port is used exclusively for inter-switch links.
  A. An access port can carry traffic for multiple VLANs.
  B. A trunk port can carry traffic for multiple VLANs.
  C. An access port carries traffic only for a single VLA

• Question 68:

  What is a VLAN?

  A. A local network using only virtual machines
  B. A broadcast domain, identified by a VLAN ID
  C. A multicast domain, identified by a VLAN ID
  D. A broadcast domain, using only virtual machines
  B. A broadcast domain, identified by a VLAN ID

• Question 69:

  What are two reasons why you would deploy an IP fabric instead of a traditional Layer 2 network in a data center? (Choose two.)

  A. Layer 2 networks only support a single broadcast domain.
  B. IP fabrics are better suited to smaller networks where scale is less important.
  C. Layer 3 networks support load balancing.
  D. Layer 2 networks are susceptible to loops.
  C. Layer 3 networks support load balancing.
  D. Layer 2 networks are susceptible to loops.

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  Explanation/Reference:

  IP fabricsare Layer 3-centric network designs often used in data centers due to their scalability, efficient routing, and loop-free architecture.

  Step-by-Step Breakdown:

  Layer 3 Load Balancing:IP fabrics use Equal-Cost Multipath (ECMP) to distribute traffic across multiple paths, providing effective load balancing and improving bandwidth utilization. This capability is absent in traditional Layer 2 networks,

  which do not support ECMP for routing decisions.

  Layer 2 Loops: Layer 2 networks are prone to loops because of the lack of TTL (Time-to-Live) mechanisms. Spanning Tree Protocol (STP) is required to prevent loops, but it can introduce inefficiencies by blocking links. In contrast, IP fabrics

  based on Layer 3 protocols are loop-free and do not need STP.

  Juniper Reference:

  IP Fabric: Juniper's IP fabric solutions offer efficient Layer 3 routing with built-in load balancing and loop prevention, making them ideal for modern data center architectures.

• Question 70:

  Which three actions are required to implement filter-based forwarding? (Choose three.)

  A. You must create an instance-type forwarding routing instance.
  B. You must create an instance-type vrf routing instance.
  C. You must create a match filter.
  D. You must create a security policy.
  E. You must create a RIB group.
  A. You must create an instance-type forwarding routing instance.
  C. You must create a match filter.
  E. You must create a RIB group.

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  Explanation/Reference:

  Filter-Based Forwarding (FBF) in Junos OS allows traffic to be routed based on specific criteria such as source address, rather than just the destination address. This is useful in scenarios like policy routing or providing multiple paths for

  different types of traffic.

  Step-by-Step Breakdown:

  Instance-Type Forwarding:You must create an instance-type forwarding routing instance. This routing instance allows for different routing tables based on the incoming packet filter.

  Command:

  set routing-instances FBF-instance instance-type forwarding

  Match Filter:You need to create a filter to match the traffic that will be forwarded according to your custom routing policy. This filter is applied to an interface to determine which traffic will use the custom forwarding instance.

  Command Example:

  set firewall family inet filter FBF-filter term 1 from source-address

  set firewall family inet filter FBF-filter term 1 then routing-instance FBF-instance

  RIB Group:A RIB (Routing Information Base) group is necessary to share routes between the primary routing table and the custom routing instance. This allows FBF traffic to use the routing information from other routing tables.

  Command Example:

  set routing-options rib-groups FBF-group import-rib inet.0

  set routing-instances FBF-instance routing-options rib-group FBF-group

  Juniper Reference:

  FBF Configuration: Filter-based forwarding requires these specific steps to redirect traffic to a custom routing table based on filter criteria.