JN0-683 : BUNDLE PACK LEARNING TOOLS INCLUDED

JN0-683 Data Center Professional Exam

Exam Code JN0-683
Prerequisite Certification JNCIS-DC or JNCIS-ENT
Exam Length 90 minutes
Exam Type 65 multiple-choice questions
Software Versions Junos OS: 23.4
Recommended Training Data Center Fabric with EVPN and VXLAN

Exam Resources
Industry/product knowledge Juniper TechLibrary
Additional Preparation Juniper Learning Portal

The Data Center track enables you to demonstrate competence with advanced data center technologies and related configuration and troubleshooting skills. JNCIP-DC, the professional-level certification in this track, is designed for experienced data center networking professionals with advanced knowledge of the Juniper Networks Junos software and data center devices. The written exam verifies your understanding of data center technologies, related platform configuration, and troubleshooting skills.

This track includes four certifications:
JNCIA-DC: Data Center, Associate. For details, see JNCIA-DC.
JNCIS-DC: Data Center, Specialist. For details, see JNCIS-DC.
JNCIP-DC: Data Center, Professional. For details, see the sections below.
JNCIE-DC: Data Center, Expert. For details, see JNCIE-DC.

Exam Preparation
We recommend the following resources to help you prepare for your exam. However, these resources aren't required, and using them doesn't guarantee you'll pass the exam.

Exam Objectives
Here’s a high-level view of the skillset required to successfully complete the JNCIP-DC certification exam.

Exam Objective
Data Center Deployment and Management
Describe data center deployment concepts.
Zero-touch provisioning (ZTP)
Dynamic Host Configuration Protocol (DHCP)

Describe data center management concepts.
Monitoring
Analytics (telemetry)
Layer 3 Fabrics

Describe IP fabric concepts.
IP fabric architecture
IP fabric routing
IP fabric scaling
IP fabric Class of Service (RDMA/RoCE)
IP fabric best practices

Demonstrate knowledge of configuring, monitoring, or troubleshooting an IP fabric.
VXLAN
Describe VXLAN concepts.
VXLAN control planes
Data plane

Demonstrate knowledge of configuring, monitoring, or troubleshooting VXLAN.
EVPN-VXLAN Signaling

Describe EVPN concepts.
Route types
EVPN multicast
Multiprotocol BGP (MBGP)
EVPN architectures (CRB and ERB)
MAC learning
Symmetric routing

Demonstrate knowledge of configuring, monitoring, or troubleshooting EVPNs.
Data Center Interconnect

Describe Data Center Interconnect (DCI) concepts.
Interconnect network types
Layer 2 and Layer 3 stretch
Stitching
EVPN-signaled VXLAN for DCI

Demonstrate knowledge of configuring, monitoring, or troubleshooting DCI.
Data Center Multitenancy and Security
Describe single tenant and multitenant architectures.
Tenant traffic isolation (Layer 3 or Layer 2)
Multitenancy (for example, routing instances)

Describe data center security concepts.
Filter-based forwarding
Group-based policy (GBP)

Exam Details
Exam questions are derived from the recommended training and the exam resources listed above. Pass/fail status is available immediately after taking the exam. The exam is only provided in English.

Recertification
Juniper certifications are valid for three years. For more information, see Recertification.

Sample Question and Answers

QUESTION 1
Exhibit.
A VXLAN tunnel has been created between leaf1 and Ieaf2 in your data center. Referring to the exhibit, which statement is correct?

A. Traffic sent from server1 to server2 will be dropped on Ieaf2.
B. Traffic sent from server1 to server2 will be tagged with VLAN ID 100 on Ieaf2 and forwarded to server2.
C. Traffic sent from server1 to server2 will be tagged with VLAN ID 200 on Ieaf2 and forwarded to server2.
D. Traffic sent from server1 to server2 will be dropped on leaf1.

Answer: C

Explanation:
Understanding VXLAN Tunneling:
VXLAN (Virtual Extensible LAN) is a network virtualization technology that addresses the scalability
issues associated with traditional VLANs. VXLAN encapsulates Ethernet frames in UDP, allowing Layer
2 connectivity to extend across Layer 3 networks.
Each VXLAN network is identified by a unique VXLAN Network Identifier (VNI). In this exhibit, we
have two VNIs, 5100 and 5200, assigned to the VXLAN tunnels between leaf1 and leaf2.

Network Setup Details:
Leaf1: Connected to Server1 with VLAN ID 100 and associated with VNI 5100.
Leaf2: Connected to Server2 with VLAN ID 200 and associated with VNI 5200.
Spine: Acts as the interconnect between leaf switches.

Traffic Flow Analysis:
When traffic is sent from Server1 to Server2, it is initially tagged with VLAN ID 100 on leaf1.
The traffic is encapsulated into a VXLAN packet with VNI 5100 on leaf1.
The packet is then sent across the network (via the spine) to leaf2.
On leaf2, the VXLAN header is removed, and the original Ethernet frame is decapsulated.
Leaf2 will then associate this traffic with VLAN ID 200 before forwarding it to Server2.

Correct Interpretation of the Exhibit:
The traffic originating from Server1, which is tagged with VLAN ID 100, will be encapsulated into
VXLAN and transmitted to leaf2.
Upon arrival at leaf2, it will be decapsulated, and since it is associated with VNI 5200 on leaf2, the
traffic will be retagged with VLAN ID 200.
Therefore, the traffic will reach Server2 tagged with VLAN ID 200, which matches the network configuration shown in the exhibit.

Data Center Reference:
This configuration is typical in data centers using VXLAN for network virtualization. It allows isolated
Layer 2 segments (VLANs) to be stretched across Layer 3 boundaries while maintaining distinct VLAN IDs at each site.
This approach is efficient for scaling large data center networks while avoiding VLAN ID exhaustion
and enabling easier segmentation.
In summary, the correct behavior, as per the exhibit and the detailed explanation, is that traffic sent
from Server1 will be tagged with VLAN ID 200 when it reaches Server2 via leaf2. This ensures proper
traffic segmentation and handling across the VXLAN-enabled data center network.

QUESTION 2
Exhibit.
You have implemented an EVPN-VXLAN data center. Device served must be able to communicate with device server2.
Referring to the exhibit, which two statements are correct? (Choose two.)

A. An IRB interface must be configured on spinel and spine2.
B. Traffic from server1 to server2 will transit a VXLAN tunnel to spinel or spine2. then a VXLAN tunnel from spinel or spine2 to Ieaf2.
C. An IRB Interface must be configured on leaf1 and Ieaf2.
D. Traffic from server! to server2 will transit the VXLAN tunnel between leaf1 and Ieaf2.

Answer: CD

Explanation:
Understanding the Exhibit Setup:
The network diagram shows an EVPN-VXLAN setup, a common design for modern data centers
enabling Layer 2 and Layer 3 services over an IP fabric.
Leaf1 and Leaf2 are the leaf switches connected to Server1 and Server2, respectively, with each
server in a different subnet (172.16.1.0 and 172.16.2.0).
Spine1 and Spine2 are part of the IP fabric, interconnecting the leaf switches.
EVPN-VXLAN Basics:
EVPN (Ethernet VPN) provides Layer 2 and Layer 3 VPN services using MP-BGP.
VXLAN (Virtual Extensible LAN) encapsulates Layer 2 frames into Layer 3 packets for transmission across an IP network.
VTEP (VXLAN Tunnel Endpoint) interfaces on leaf devices handle VXLAN encapsulation and decapsulation.
Integrated Routing and Bridging (IRB):
IRB interfaces are required on leaf1 and leaf2 (where the endpoints are directly connected) to route
between different subnets (in this case, between 172.16.1.0 and 172.16.2.0).
The IRB interfaces provide the necessary L3 gateway functions for inter-subnet communication.

Traffic Flow Analysis:
Traffic from Server1 (172.16.1.1) destined for Server2 (172.16.2.1) must traverse from leaf1 to leaf2.
The traffic will be VXLAN encapsulated on leaf1, sent over the IP fabric, and decapsulated on leaf2.
Since the communication is between different subnets, the IRB interfaces on leaf1 and leaf2 are
crucial for routing the traffic correctly.

Correct Statements:
C . An IRB Interface must be configured on leaf1 and leaf2: This is necessary to perform the intersubnet routing for traffic between Server1 and Server2.
D . Traffic from server1 to server2 will transit the VXLAN tunnel between leaf1 and leaf2: This describes the correct VXLAN operation where the traffic is encapsulated by leaf1 and decapsulated by leaf2. Data Center Reference: In EVPN-VXLAN architectures, the leaf switches often handle both Layer 2 switching and Layer 3
routing via IRB interfaces. This allows for efficient routing within the data center fabric without the
need to involve the spine switches for every routing decision.
The described traffic flow aligns with standard EVPN-VXLAN designs, where direct VXLAN tunnels
between leaf switches enable seamless and scalable communication across a data center network.

QUESTION 3
Which statement is correct about a collapsed fabric EVPN-VXLAN architecture?

A. Fully meshed back-to-back links are needed between the spine devices.
B. It supports multiple vendors in the fabric as long as all the spine devices are Juniper devices deployed with L2 VTEPs
C. Using Virtual Chassis at the leaf layer increases resiliency.
D. Border gateway functions occur on border leaf devices.

Answer: D

Explanation:
Collapsed Fabric Architecture:
A collapsed fabric refers to a simplified architecture where the spine and leaf roles are combined, often reducing the number of devices and links required.
In this architecture, the spine typically handles core switching, while leaf switches handle both access and distribution roles.
Understanding Border Gateway Functionality:
Border gateway functions include connecting the data center to external networks or other data centers.
In a collapsed fabric, these functions are usually handled at the leaf level, particularly on border leaf
devices that manage the ingress and egress of traffic to and from the data center fabric.

Correct Statement:
D . Border gateway functions occur on border leaf devices: This is accurate in collapsed fabric
architectures, where the border leaf devices take on the role of managing external connections and
handling routes to other data centers or the internet.

Data Center Reference:
The collapsed fabric model is advantageous in smaller deployments or scenarios where simplicity
and cost-effectiveness are prioritized. It reduces complexity by consolidating functions into fewer
devices, and the border leaf handles the critical task of interfacing with external networks.
In conclusion, border gateway functions are effectively managed at the leaf layer in collapsed fabric
architectures, ensuring that the data center can communicate with external networks seamlessly.

QUESTION 4
You are deploying an EVPN-VXLAN overlay. You must ensure that Layer 3 routing happens on the spine devices. In this scenario, which deployment architecture should you use?

A. ERB
B. CRB
C. bridged overlay
D. distributed symmetric routing

Answer: B

Explanation:
Understanding EVPN-VXLAN Architectures:
EVPN-VXLAN overlays allow for scalable Layer 2 and Layer 3 services in modern data centers.
CRB (Centralized Routing and Bridging): In this architecture, the Layer 3 routing is centralized on
spine devices, while the leaf devices focus on Layer 2 switching and VXLAN tunneling. This setup is
optimal when the goal is to centralize routing for ease of management and to avoid complex routing at the leaf level.
ERB (Edge Routing and Bridging): This architecture places routing functions on the leaf devices,
making it a distributed model where each leaf handles routing for its connected hosts.
Architecture Choice for Spine Routing:
Given the requirement to ensure Layer 3 routing happens on the spine devices, the CRB (Centralized
Routing and Bridging) architecture is the correct choice. This configuration offloads routing tasks to
the spine, centralizing control and potentially simplifying the overall design.

Explanation:
With CRB, the spine devices perform all routing between VXLAN segments. Leaf switches handle
local switching and VXLAN encapsulation, but routing decisions are centralized at the spine level.
This model is particularly advantageous in scenarios where centralized management and routing
control are desired, reducing the complexity and configuration burden on the leaf switches.

Data Center Reference:
The CRB architecture is commonly used in data centers where centralized control and simplified
management are key design considerations. It allows the spines to act as the primary routing
engines, ensuring that routing is handled in a consistent and scalable manner across the fabric.

QUESTION 5
You want to ensure that VXLAN traffic from the xe-0/0 interlace is being encapsulated by logical
vlep.32770 and sent to a remote leaf device in this scenario, which command would you use to verify that traffic is flowing?

A. monitor traffic interface xe-0/0
B. show interface terse vtep.32770
C. show interfaces terse vtep.32770 statistics
D. show interfaces vtep.32770 detail

Answer: C

Explanation:
VXLAN Traffic Verification:
To ensure VXLAN traffic from the xe-0/0 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.

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