Juniper JN0-683 Data Center Professional Exam Practice Test

Answer : D, D

Understanding VRF and Routing Instances:

In an EVPN-VXLAN overlay network, multiple tenants are separated using unique VRF (Virtual Routing and Forwarding) instances. Each VRF instance maintains its own routing table, allowing for isolated routing domains within the same network infrastructure.

Role of Route Distinguisher:

Route Distinguisher (RD): The RD is a unique identifier used in MPLS and EVPN environments to distinguish routes belonging to different VRFs. The RD is prepended to the IP address in the route advertisement, ensuring that routes from different tenants remain unique even if they use the same IP address range.

Correct Property:

Answer : B, D

Understanding the Configuration:

The exhibit shows configurations for two VRFs (Customer_A and Customer_B) with specific VLANs and VNIs assigned. Each VRF has interfaces (IRBs) associated with particular VLANs.

Communication Between VLANs and Routing Instances:

Option B: VLAN 400 (irb.400) is part of Customer_B, and there is no direct connection or routing between Customer_A and Customer_B in the configuration provided. Therefore, devices in irb.400 cannot communicate directly with devices in the Customer_A routing instance.

Option D: Since irb.400 (VLAN 400) and irb.800 (VLAN 800) are part of the same routing instance (Customer_B), they can communicate over the fabric using VXLAN encapsulation.

Conclusion:

Option B: Correct---There is no direct communication between devices in irb.400 (Customer_B) and routing instance Customer_A.

Option D: Correct---Devices in VLAN 400 and VLAN 800 can communicate within the Customer_B routing instance over the fabric.

Answer : C

VXLAN Traffic Verification:

To ensure VXLAN traffic from the xe-0/0/12 interface is correctly encapsulated by the logical vtep.32770 and sent to a remote leaf device, it is essential to monitor the relevant interface statistics.

The command show interfaces terse vtep.32770 statistics provides a concise overview of the traffic statistics for the specific VTEP interface, which can help verify whether traffic is being correctly encapsulated and transmitted.

This command is particularly useful for quickly checking the traffic counters and identifying any potential issues with VXLAN encapsulation or transmission.

It allows you to confirm that traffic is flowing as expected, by checking the transmitted and received packet counters.

Data Center Reference:

Monitoring interface statistics is a crucial step in troubleshooting and validating network traffic, particularly in complex overlay environments like EVPN-VXLAN.

Answer : C

Scenario Overview:

Converting an MX Series router from a VXLAN Layer 2 gateway to a VXLAN Layer 3 gateway involves transitioning the router's functionality from simply bridging traffic within a VXLAN segment to routing traffic between different segments.

Key Configuration Requirement:

IRB (Integrated Routing and Bridging) Interface: An IRB interface allows for both Layer 2 switching and Layer 3 routing. To enable routing for a specific VNI (VXLAN Network Identifier), the IRB interface must be associated with the routing function in the corresponding bridge domain.

Correct Command:

C . set bridge-domains VLAN-100 routing-interface irb.100: This command correctly binds the IRB interface to the bridge domain, enabling Layer 3 routing functionality within the VXLAN for VNI 100. This effectively transitions the device from operating solely as a Layer 2 gateway to a Layer 3 gateway.

Data Center Reference:

This configuration step is essential when converting a Layer 2 VXLAN gateway to a Layer 3 gateway, enabling the MX Series router to route between VXLAN segments.

Answer : A, D

Understanding BGP Configuration in the Exhibit:

The exhibit shows a BGP configuration on spine1 with a group named underlay, configured to peer with directly connected interfaces of other devices in the network.

Multipath multiple-as: This statement allows the router to install multiple paths in the routing table for routes learned from different ASes, facilitating load balancing.

Key Statements:

A . The multihop statement is not required to establish the underlay BGP sessions: In this case, the BGP peers are directly connected (as indicated by their neighbor IP addresses), so the multihop statement is unnecessary. Multihop is typically used when BGP peers are not directly connected and packets need to traverse multiple hops.

D . Load balancing for the underlay is configured correctly: The multipath { multiple-as; } statement in the configuration enables load balancing across multiple paths from different autonomous systems, which is appropriate for underlay networks in data center fabrics.

Incorrect Statements:

C . The multihop statement is required to establish the underlay BGP sessions: This is incorrect because the peers are directly connected, making the multihop statement unnecessary.

B . Load balancing for the underlay is not configured correctly: This is incorrect because the configuration includes the necessary multipath settings for load balancing.

Data Center Reference:

BGP configurations in EVPN-VXLAN underlay networks are crucial for ensuring redundancy, load balancing, and efficient route propagation across the data center fabric.

Answer : D

Understanding the Configuration:

The configuration shown in the exhibit involves an EVPN (Ethernet VPN) setup using BGP as the routing protocol. The export policy named CHANGE_NH is applied to the BGP group evpn-peer, which includes a rule to change the next hop for routes that match the policy.

Issue with Next Hop Not Changing:

The policy CHANGE_NH is correctly configured to change the next hop to 203.0.113.10 for the matching routes. However, the next hop remains unchanged when advertising EVPN routes to the peer 203.0.113.2.

Reason for the Issue:

In Junos OS, when exporting routes for VPNs (including EVPN), the next-hop change defined in a policy will not take effect unless the vpn-apply-export parameter is used in the BGP configuration. This parameter ensures that the export policy is applied specifically to VPN routes.

The vpn-apply-export parameter must be included to apply the next-hop change to EVPN routes.

Correct Answer Explanation:

D . The vpn-apply-export parameter must be applied to this peer: This is the correct solution because the next hop in EVPN routes won't be altered without this parameter in the BGP configuration. It instructs the BGP process to apply the export policy to the EVPN routes.

Data Center Reference:

This behavior is standard in EVPN deployments with Juniper Networks devices, where the export policies applied to VPN routes require explicit invocation using vpn-apply-export to take effect.

Answer : C, E

Issue Analysis:

The problem in the exhibit suggests a mismatch in configuration parameters between Leaf-1 and Leaf-2, leading to communication issues between hosts connected to these leaf devices.

Configuration Mismatches:

Service-ID: Leaf-1 has service-id 1 configured, while Leaf-2 does not have this parameter. For consistency and proper operation, the service-id should be the same across both leaf devices.

VRF Target: Leaf-1 is configured with vrf-target target:65000:1, while Leaf-2 is configured with vrf-target target:65000:2. To allow proper VRF import/export between the two leafs, these should match.

Corrective Actions:

C . Configure the set switch-options vrf-target target:65000:1 parameter on Leaf-2: This aligns the VRF targets between the two leaf devices, ensuring they can correctly import and export routes.

E . Configure the set switch-options service-id 1 parameter on Leaf-2: This ensures that both Leaf-1 and Leaf-2 use the same service ID, which is necessary for consistency in the EVPN-VXLAN setup.

Data Center Reference:

Correct configuration of VRF targets and service IDs is critical in EVPN-VXLAN setups to ensure that routes and services are correctly shared and recognized between different devices in the network fabric.