JNCIP-ENT EVPN Practice Test 3 — 15 Questions

Question 1

You are analyzing BGP EVPN updates and observe an Extended Community attached to a Type-2 route containing a sequence number. What is the primary function of this MAC Mobility Extended Community?

Accepted Answer

It facilitates loop-free MAC movement tracking by incrementing sequence numbers when a host changes attachment PEs.. The MAC Mobility Extended Community carries a sequence number used to resolve MAC moves. If a host moves from one PE to another, the new PE advertises the MAC with an incremented sequence number, causing all other PEs to update their tables to point to the new location.

Answer

It signals the EVPN split-horizon label for BUM traffic.

Answer

It determines the Designated Forwarder for multi-homed Ethernet segments.

Answer

It defines the VXLAN Network Identifier (VNI) mapping for data-plane decapsulation.

Question 2

Which EVPN route type is responsible for establishing ingress replication lists for Broadcast, Unknown Unicast, and Multicast (BUM) traffic?

Accepted Answer

Route Type 3. Route Type 3 (Inclusive Multicast Ethernet Tag Route) is used to build the peer list for BUM traffic distribution using ingress replication (head-end replication).

Answer

Route Type 5

Answer

Route Type 4

Answer

Route Type 1

Question 3

An administrator configures EVPN with VXLAN encapsulation and wants to ensure that interfaces assigned to bridge domains drop frames whose source MAC address is not learned or is unauthorized. Which feature should be enabled?

Accepted Answer

MAC security / MAC limit with drop action. Configuring MAC limit or bpdu protection/port security features on access interfaces prevents unauthorized MAC learning, while EVPN sticky MAC features can lock MACs to specific interfaces.

Answer

Ingress replication disabling

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BGP route filtering

Answer

EVPN Route Type 4 filtering

Question 4

Which command allows an operator to view the local and remote MAC addresses learned via EVPN control plane and data plane across all bridge domains on an MX Series router?

Accepted Answer

show evpn database. The 'show evpn database' command displays the EVPN routing/MAC table containing MAC addresses learned via BGP EVPN control plane and local data plane learning.

Answer

show bridge domain

Answer

show route table inet.0

Answer

show mpls lsp

Question 5

An engineer configures an EVPN instance with multiple bridge domains. Each bridge domain requires a unique VNI. Where are the VNI values mapped to their respective bridge domains in Junos OS?

Accepted Answer

Under routing-instances bridge-domains vni . In Junos OS, VNI values are mapped under the 'bridge-domains' hierarchy using the 'vni ' statement.

Answer

Under protocols bgp neighbor configuration

Answer

Under interfaces loopback unit 0 vni

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Under policy-options community definition

Question 6

Which TWO of the following statements regarding EVPN Route Type 1 (Ethernet Auto-Discovery Route) are correct? (Choose two)

Accepted Answer

Type 1 routes are advertised either per-EVI or per-Ethernet Segment (ES).. Route Type 1 comes in two variants: per-EVI and per-ES. Per-EVI routes provide aliasing for load-balancing across multi-homed PEs, and per-ES routes facilitate fast convergence during node failures.

Answer

Type 1 routes are only used in single-homed network topologies.

Answer

Type 1 routes are exclusively used for mapping IP prefixes to IP-VRFs.

Answer

Type 1 routes replace Type 3 routes for handling BUM traffic replication.

Question 7

Which TWO of the following statements accurately describe EVPN Route Type 2 (MAC/IP Advertisement Route)? (Choose two)

Accepted Answer

It can carry both a MAC address and an IP address in a single control-plane update.. Type 2 routes advertise MAC addresses and optionally host IP addresses. They play a critical role in both Layer 2 bridging and Integrated Routing and Bridging (IRB) host reachability.

Answer

It is exclusively used to elect the Designated Forwarder for multicast traffic.

Answer

It is only generated when BUM traffic flooding occurs.

Answer

It replaces BGP L3VPN route targets for core routing.

Question 8

When configuring EVPN multi-homing in all-active mode, which THREE key components or concepts must be properly established across the PE routers? (Choose three)

Accepted Answer

A Designated Forwarder (DF) election mechanism using Type-4 routes to determine who forwards BUM traffic.. EVPN all-active multi-homing requires a consistent Ethernet Segment Identifier (ESI) across participating PEs, an active Designated Forwarder election (governed by Type-4 routes), and split-horizon filtering to prevent traffic loops.

Answer

Enabling Spanning Tree Protocol root bridge on all leaf nodes.

Answer

Configuring OSPF as the underlay routing protocol for EVPN signaling.

Question 9

When troubleshooting EVPN control plane connectivity in Junos OS, which THREE commands provide essential diagnostic information regarding EVPN routing tables and peers? (Choose three)

Accepted Answer

show route table bgp.evpn.0. To troubleshoot EVPN control plane issues, commands like 'show route table bgp.evpn.0', 'show bgp summary', and 'show evpn database' are essential for verifying route tables, neighbor status, and MAC databases.

Answer

show mpls lsp extensive

Answer

show spanning-tree interface

Question 10

Which THREE parameters are typically included or evaluated when configuring and verifying BGP EVPN peer sessions on Junos OS devices? (Choose three)

Accepted Answer

Route targets (import and export) to control the exchange of EVPN routes between routing instances.. BGP EVPN peering requires the BGP neighbor IP/address family configuration, Route Targets for import/export control, and Route Distinguishers for uniqueness within the routing instance.

Answer

RSVP bandwidth reservation for the BGP TCP session.

Answer

Spanning tree priority configuration for the BGP peering interface.

Question 11

Which THREE of the following statements describe the behavior and purpose of EVPN Route Type 5 (IP Prefix Route)? (Choose three)

Accepted Answer

It is frequently used for inter-subnet routing and integration with MPLS L3VPN backbones.. Route Type 5 carries IP prefixes independently of MAC addresses, supports inter-subnet forwarding in IP-VRF or EVPN-VXLAN integrations, and can carry gateway IP information.

Answer

It is mandatory for establishing basic Layer 2 bridging across a single VLAN.

Answer

It replaces Ethernet Segment Identifiers on multi-homed ports.

Question 12

Which TWO factors can cause an EVPN instance on a Junos device to fail in importing incoming Type-2 MAC/IP routes? (Choose two)

Accepted Answer

The EVPN routing instance is missing or has an incorrect instance-type configured.. Route import failures in EVPN are typically caused by mismatched Route Targets between the advertising and receiving PE, or missing/incorrect EVPN routing instance configurations.

Answer

Configuring an incorrect BGP router ID on the remote peer.

Answer

Enabling MAC limit suppression on access ports.

Answer

Incorrect loopback MTU settings on the physical underlay interfaces.

Question 13

When designing an EVPN-VXLAN fabric with integrated routing and bridging (IRB), which THREE considerations are critical for proper inter-subnet forwarding across VTEPs? (Choose three)

Accepted Answer

Configuring consistent virtual gateway MAC and IP addresses on all IRB interfaces across leaf VTEPs.. Distributed IRB gateways require consistent anycast gateway MAC and IP configurations across all leaf nodes, correct VNI to bridge domain mappings, and EVPN Type-5 or Type-2 route propagation for host/subnet reachability.

Answer

Enforcing physical loopback interfaces to run in layer 2 bridging mode.

Answer

Disabling BGP EVPN signaling on all spine nodes to save CPU resources.

Question 14

Which THREE actions occur during the EVPN Designated Forwarder (DF) election process on a multi-homed Ethernet segment? (Choose three)

Accepted Answer

A Designated Forwarder is elected to forward BUM traffic from the core to the multi-homed site.. DF election uses Route Type 4 (Ethernet Segment routes) to exchange reachability, determines the forwarder based on preference and algorithms, and assigns responsibility for BUM traffic forwarding.

Answer

All participating PEs simultaneously forward BUM traffic to maximize bandwidth utilization.

Answer

MAC mobility sequence numbers are reset to zero during the election.

Question 15

Which TWO of the following statements correctly describe the operation and benefits of EVPN MAC mobility? (Choose two)

Accepted Answer

It uses sequence numbers attached to Type-2 routes to track host movement between different PEs.. EVPN MAC mobility uses sequence numbers in the MAC Mobility Extended Community to detect when a host moves between PEs, preventing blackholing and updating forwarding tables correctly.

Answer

It forces BGP session resets whenever a MAC address moves between subnets.

Answer

It is exclusively used for Route Type 4 Designated Forwarder election.

Answer

It requires Spanning Tree Protocol to be enabled to detect host migration.