Juniper JN0-682 Data Center Professional (JNCIP-DC) Exam Practice Test

For building an IP fabric underlay network in a data center, it is recommended that all spine devices are identical models, including the same installed line cards, to ensure uniformity and predictable performance. Additionally, each leaf device should have an identical uplink to every spine device to ensure consistent

and predictable load-balancing behavior across the network. This uniformity in spine and leaf configurations helps in achieving optimal and predictable data paths, thereby enhancing overall network efficiency and stability.References:Juniper Networks Technical Documentation, Data Center Design Considerations.

Setting the Virtual Chassis as auto-provisioned (A) and configuring the auto-sw-update parameter (D) are key to enabling plug-and-play functionality for line card switches in an active VCF. This ensures that new line cards are automatically recognized and updated to the correct Junos version without manual intervention.

References:

• Juniper Networks - Virtual Chassis Fabric Configuration Guide

A. If BGP multipath is not configured, traffic may not be load-balanced across multiple paths. B. Without proper load-balancing policies, traffic distribution might not be optimal. D. Insufficient bandwidth between spine and leaf can lead to congestion and affect load balancing.

In a scenario where RSVP and LDP are restricted, and routes are not appearing in the inet table, the use of "bgp family inet labeled-unicast per-group-label" becomes necessary. This setting is crucial in environments where label distribution protocols like RSVP or LDP are not used. It enables the use of MPLS labels in BGP without relying on these protocols, which is essential for integrating L3VPN with EVPN over WAN links that do not support RSVP or LDP. The “per-group-label” option ensures that a single label is used for all routes exchanged with a BGP neighbor, which simplifies label management and conserves label space.References:

• Junos OS Routing Protocols Library for Routing Devices

Ethernet VPN (EVPN) provides control plane-based MAC address learning. This means that MAC addresses are exchanged and learned via BGP messages rather than through traditional data plane flooding. This approach is more scalable and reliable compared to multicast-based MAC address learning, where MAC addresses are learned through data plane flooding. Control plane learning with EVPN is less prone to issues like broadcast storms and provides a more efficient and stable mechanism for MAC address dissemination in large-scale networks.References:Juniper Networks EVPN Overview and Configuration Guide.

In a DCI (Data Center Interconnect) scenario where IP subnets between data centers are completely unique, Type 5 EVPN routes (IP Prefix routes) are used. These routes allow for the advertisement of IP prefixes over the EVPN, facilitating inter-data center communication without IP overlap issues.

https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/ztp-configuring.html 6. Configure the following DHCP option 43 suboptions: • Suboption 01: The name of the script or configuration file to install.

In a spine and leaf-based IP fabric, when a device or link fails, the traffic is rerouted within the fabric (A), ensuring high availability and resiliency. This architecture is designed to dynamically adapt to changes and reroute traffic as needed. Furthermore, Clos networks, which are the basis for spine-leaf architectures, demonstrate good scaling features (D) as they allow for easy expansion of the network by adding more spine or leaf switches without significant changes to the existing infrastructure.References:

• Juniper Networks - Spine-and-Leaf Architectures
• Understanding Spine-and-Leaf Network Topologies

For enabling visibility into EVPN-VXLAN network traffic through continuous monitoring:

• You must enable sFlow monitoring on each interface individually (Option C):sFlow is a sampling technology used for monitoring network traffic. In a Juniper environment, sFlow needs to be enabled on individual interfaces to start collecting traffic samples. This allows for granular control over which interfaces are monitored.
• You cannot enable sFlow monitoring on each interface individually (Option A):This statement is incorrect, contradicting the above explanation. sFlow can and should be enabled on specific interfaces as needed.

The option stating that the sFlow agent needs to be manually installed on QFX Series switches (Option D) is inaccurate, as the sFlow feature is typically integrated into the Junos OS running on QFX Series switches. The statement about the sFlow agent being installed by default on QFX Series switches (Option B) is partially true but does not directly address the question of enabling visibility into network traffic.

References

• Juniper Networks: Configuring sFlow Technology for Network Monitoring

A. By default, Junos switches operate in non-mixed mode Virtual Chassis, meaning they are configured to operate with similar or identical device models.

B. The commandrequest virtual-chassis mode fabric rebootis used to set the Virtual Chassis to fabric mode with similar devices. This mode is specifically designed for configurations that involve similar devices to optimize performance and capabilities.

B. Configure virtual-gateway-accept-data under the IRB interface. This configuration is necessary to ensure that the IRB interfaces on the spine devices can handle traffic destined to the virtual gateway IP address.

D. Configure proxy-macip-advertisement under the IRB interface. This enables the advertisement of proxy MAC/IP routes to remote VTEPs. This is essential in a CRB (Centralized Routing and Bridging) topology to ensure that all hosts, including those connected to the spine devices, have reachability to all IRB interface addresses.

References:

• Juniper EVPN Configuration Guide

In a Clos data center network, scaling the available bandwidth to support more east-west traffic can be effectively achieved by either adding more leaf devices (A) or more spine devices (C). Adding leaf devices increases the total number of endpoints in the network, thereby providing additional paths and bandwidth for east-west traffic. Similarly, adding spine devices increases the interconnectivity within the network, offering more paths for traffic to flow through, which helps in handling higher volumes of east-west traffic. Both approaches work towards enhancing the overall capacity and efficiency of the network.References:

• Juniper Networks - Understanding Clos Networks
• Juniper Networks - Data Center Network Design Considerations

In an EVPN-VXLAN environment, to ensure that multicast traffic is delivered only to leaf devices with interested receivers, IGMP snooping is required. IGMP snooping enables the leaf devices to listen to IGMP report and leave messages from hosts and make forwarding decisions based on this information. This way, multicast traffic is only forwarded to ports with interested multicast group members, optimizing bandwidth and resource utilization.References:

• EVPN-VXLAN Configuration Guide

A. EVPN signaling reduces ARP flooding, while multicast signaling does not. EVPN uses BGP to distribute MAC address information, which can also include IP address bindings, thereby eliminating the need for ARP flooding across the VXLAN overlay. B. EVPN signaling propagates MAC addresses across the network, while multicast signaling does not. In an EVPN environment, MAC address advertisements are distributed via BGP EVPN routes, enabling efficient and scalable MAC address learning and distribution.

References:

• EVPN Overview

To accommodate the extra header information added by VXLAN, which can be 50 to 54 bytes, it's necessary to increase the MTU (Maximum Transmission Unit) on the physical interfaces connected to the VXLAN network. This ensures that the larger frames can be transmitted without fragmentation, maintaining efficient network performance.

The Ethernet segment router in EVPN is responsible for preventing BUM traffic from looping back to a multi-homed host. It ensures that BUM traffic is properly handled in scenarios where hosts are connected to multiple leaf nodes.

Using separate vSwitches for each tenant's network in conjunction with a vSRX device allows for effective isolation and deep packet inspection of inter-tenant traffic. The vSRX can inspect traffic at the hypervisor level without the need for traffic to leave the physical device.

References:

• Juniper Networks - vSRX Virtual Firewall

The Junos Telemetry Interface (JTI) is the ideal solution for monitoring and telemetry in an IP fabric using QFX Series devices. JTI uses a push model to stream system event data and statistical data from the devices. It provides real-time, granular monitoring capabilities, which is more efficient and scalable compared to

traditional polling methods like SNMP. By pushing data to a telemetry server, JTI allows for more dynamic and immediate insights into network performance and health.References:Juniper Networks QFX Series Documentation - Junos Telemetry Interface.

A. VPLS (Virtual Private LAN Service) learns MAC addresses in the data plane, meaning the learning process occurs as the traffic flows through the network.

D. EVPN (Ethernet VPN) differs from VPLS in that it learns MAC addresses in the control plane, using BGP for MAC address dissemination, which offers better scalability and control.

References:

• Juniper Networks - Understanding VPLS
• Juniper Networks - Understanding EVPN

A. Route distinguishers (RDs) ensure that routes from different clients remain unique within the data center domain by appending a unique identifier to each route, allowing overlapping IP spaces to coexist in the same network.

C. Route targets (RTs) identify the VRF into which the route should be placed. They are used in the import and export policies to control the distribution of routes among different VRFs, ensuring that routes are only shared with the intended VRFs.

Virtual Routing and Forwarding (VRF) instances allow multiple virtual routing tables to exist on a single physical router. Each VRF has its own independent routing table, which allows network paths to be segmented without interference from other VRFs. This design supports overlapping IP address spaces, enabling the same IP subnet to be used in different VRFs without conflict.

References

• Virtual Routing and Forwarding

In Zero Touch Provisioning (ZTP), the process is streamlined to simplify the deployment of new switches in the network. When a switch that supports ZTP boots and does not find a configuration file, it attempts to acquire one using DHCP. If the switch is already running the firmware image specified by the DHCP server (if mentioned), it proceeds to the next step without re-downloading the image. DHCP Option 43 suboption 01 is used by the DHCP server to provide the URL of the configuration file to the switch.

References

• Zero Touch Provisioning

A. Allowing Junos to dynamically create the virtual MAC address of the IRB interface ensures unique MAC addresses for redundancy and avoids conflicts. C. Configuring both IRB interfaces manually with the same address ensures consistency and helps in creating a redundant Layer 3 gateway setup.