Free JN0-281 sample questions

Correct answer: Spine-and-leaf architecture

A spine-and-leaf architecture (also known as a Clos network) is designed specifically for modern data centers to optimize east-west traffic. Every leaf switch connects to every spine switch, ensuring a consistent number of hops (predictable latency) and high bandwidth availability (non-blocking) between any two devices connected to the leaf layer. graph TD subgraph Spine Layer S1[Spine 1] S2[Spine 2] end subgraph Leaf Layer L1[Leaf 1] L2[Leaf 2] L3[Leaf 3] end S1 --- L1 S1 --- L2 S1 --- L3 S2 --- L1 S2 --- L2 S2 --- L3

Correct answer: True

This statement refers to EVPN. In an EVPN-VXLAN architecture, EVPN (Ethernet VPN) serves as the control plane. It uses Multiprotocol BGP (MP-BGP) to exchange MAC addresses and IP prefix information between VTEPs, replacing the traditional flood-and-learn mechanism of the data plane with a robust BGP-based control plane.

Correct answers: It provides physical connectivity and IP reachability between network devices.; It typically uses EBGP or OSPF as the routing protocol.

The underlay network is the physical infrastructure that ensures IP reachability between loopback interfaces of the spine and leaf switches, serving as the transport for the overlay.

Underlay networks commonly use robust Layer 3 protocols like EBGP or OSPF to manage loop-free paths and ECMP load balancing between spines and leaves.

Correct answer: set interfaces xe-0/0/1 unit 0 family ethernet-switching interface-mode trunk

In Junos OS, to allow an interface to carry multiple VLANs using 802.1Q tagging, the interface mode must be set to 'trunk'. The command 'set interfaces unit 0 family ethernet-switching interface-mode trunk' accomplishes this.

Correct answer: MAC addresses, associated VLANs, and the interfaces where the MACs were learned

The Ethernet switching table (often called the MAC address table) maps MAC addresses to the specific ports/interfaces where they were learned and associates them with their respective VLANs to facilitate Layer 2 forwarding.

Correct answer: set vlans vlan-100 l3-interface irb.100

To link a VLAN to a Layer 3 IRB interface in Junos, you must configure the 'l3-interface' statement within the VLAN configuration hierarchy, pointing to the specific IRB logical unit (e.g., irb.100). graph LR subgraph Configuration V[VLAN 100] -- references --> I[irb.100] I -- has --> IP[IP Address] end