JNCIP-ENT EVPN — Timed 10 Questions

Question 1

You are troubleshooting a suboptimal traffic forwarding issue in an EVPN-VXLAN fabric with multi-homed devices. Traffic destined for a multi-homed server is being sent to only one of the PEs despite all-active mode being configured. Which EVPN route type and mechanism are responsible for enabling load balancing across all available PEs attached to the same Ethernet segment?

10 minute time limit — choose an answer to begin.

Accepted Answer

Route Type 1 (Ethernet Auto-Discovery per EVI). Type 1 Ethernet A-D routes per EVI are used for multi-homing aliasing, allowing PEs that do not learn a specific MAC address locally to still load-balance traffic to that MAC across all PEs advertising the ESI via Type 1 routes.

Answer

Route Type 2 with MAC mobility extended community

Answer

Route Type 4 (Ethernet Segment Route)

Answer

Route Type 3 (Inclusive Multicast)

Question 2

You are configuring a Junos EVPN-VXLAN environment where Type-3 (Inclusive Multicast Ethernet Tag) routes are being exchanged. A remote MX router is failing to establish ingress replication tunnels because it does not import the Type-3 route. Which configuration statement under the routing-instance is missing or misconfigured?

Accepted Answer

route-target import. EVPN Type-3 routes carry the Inclusive Multicast Ethernet Tag and rely on route targets for import and export. If the import route-target does not match the advertising router's export route-target, the tunnel endpoints are not dynamically bound.

Answer

no-normalization

Answer

multicast-snooping

Answer

vtep-source-interface lo0.0

Question 3

During a maintenance window, an administrator needs to manually force a Designated Forwarder (DF) role change on a multi-homed Ethernet segment for an EVPN instance. Which parameter must be adjusted to influence the DF election algorithm in Junos OS?

Accepted Answer

Ethernet segment preference value. Junos OS allows influencing the DF election by adjusting the interface preference or local preference values associated with the Ethernet Segment, altering how the DF election algorithm selects the forwarder.

Answer

BGP AS path prepending

Answer

Route Distinguisher value

Answer

Router ID of the BGP speaker

Question 4

When configuring VXLAN data plane encapsulation inside an EVPN routing instance on Junos OS, which logical interface type must be bound to the bridge domain to provide VXLAN VNI mapping?

Accepted Answer

VLAN interface (vlan statement with vni). In Junos OS, VXLAN encapsulation is configured using logical tunnel interfaces or integrated routing and bridging (IRB) interfaces mapped via a vni statement under the bridge-domains hierarchy.

Answer

lo0.0

Answer

gre0

Answer

fxp0

Question 5

An engineer is troubleshooting EVPN type 2 routes between two MX Series routers and notices that MAC addresses learned locally are not being advertised to the remote VTEP. Which command should the engineer use to verify that the EVPN instance is actively generating and exporting MAC-VRF routes?

Accepted Answer

show route advertising-protocol bgp <neighbor-ip>. The 'show route advertising-protocol bgp' command allows an engineer to verify which routes (including EVPN type 2 MAC/IP routes) are being advertised to a specific BGP peer or peer group for an EVPN routing instance.

Answer

show bridge mac-table

Answer

show bgp summary

Answer

show evpn database

Question 6

An enterprise network architect is designing an EVPN-VXLAN fabric and wants to ensure that MAC address churn (frequent moving of a MAC between ports) does not destabilize the control plane. Which feature should be enabled in the EVPN instance?

Accepted Answer

MAC limit and MAC mobility sequence numbering. MAC mobility features, including MAC move detection and sticky MAC or suppression mechanisms, protect the EVPN control plane from frequent MAC moves by incrementing sequence numbers and applying penalties if movement thresholds are exceeded.

Answer

Spanning Tree BPDU protection

Answer

Fast-reroute backup paths

Answer

BGP route flap damping

Question 7

Which EVPN route type is known as the Ethernet Segment Route and is advertised by a PE router to signal its connectivity to a multi-homed Ethernet segment?

Accepted Answer

Route Type 4. EVPN Route Type 4 is the Ethernet Segment Route, used for discovering other PEs attached to the same Ethernet segment and executing the Designated Forwarder (DF) election.

Answer

Route Type 2

Answer

Route Type 3

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Route Type 1

Question 8

An administrator wishes to configure VXLAN data plane encapsulation on an MX Series router with an EVPN instance. Which statement under the routing-instances hierarchy defines the local VTEP source interface?

Accepted Answer

vtep-source-interface lo0.0;. In Junos OS, the VXLAN source interface is defined using the 'vtep-source-interface' statement under the EVPN routing instance or switch-options hierarchy.

Answer

encapsulation-source-interface fxp0.0;

Answer

vxlan-source-ip lo0.0;

Answer

tunnel-source loopback 0;

Question 9

You are troubleshooting a scenario where an MX Series router running an EVPN-VXLAN instance receives Type-2 routes from a remote PE, but the local data plane fails to install the forwarding entries because of a mismatch in encapsulation types. Where is the encapsulation type for VXLAN defined within a Junos EVPN instance?

Accepted Answer

routing-instances <name> instance-type evpn; ... encapsulation vxlan;. In Junos OS, the encapsulation for the routing instance or switch options is defined using the 'encapsulation vxlan' statement under the routing-instance or switch-options hierarchy.

Answer

protocols bgp group <name> family evpn encapsulation vxlan

Answer

interfaces lo0.0 family vxlan

Answer

bridge-domains vni encapsulation mpls

Question 10

Which TWO of the following characteristics apply to EVPN Route Type 3 (Inclusive Multicast Ethernet Tag Route)? (Choose two)

Accepted Answer

It carries the originating router's IP address and an Ethernet Tag/VNI identifier.. Route Type 3 routes are used to construct the multicast/broadcast distribution tree using ingress replication (head-end replication) by advertising the PE's IP address and Ethernet tag/VNI.

Answer

It advertises host IP prefixes for inter-subnet routing.

Answer

It dynamically triggers MAC mobility sequence number increments.

Answer

It performs Designated Forwarder election on multi-homed links.