The Arista 7500E series is a modular switch platform designed for large-scale cloud and data center environments. It meets all the specified criteria: it is built on a 100% efficient, non-blocking, cell-based fabric architecture. A core feature of its design is Virtual Output Queuing (VOQ) to eliminate head-of-line blocking and ensure lossless performance under congestion. The 7500 platform, which includes the 7500E chassis and compatible line cards (such as the 7500R series), supports line cards that meet and exceed the 3.84 Tbps per-slot capacity requirement, making it the only suitable choice among the options for such a high-performance, large-scale deployment.

A. 7010T: This is a fixed-configuration 1RU switch. It is not a modular chassis and does not have a cell-based fabric or the concept of per-slot capacity.

C. 7300: While the 7300 series is a modular chassis with VOQ, its highest-performing line cards typically offer capacity just below the specified 3.84 Tbps per slot.

D. 7150: This is a fixed-configuration 1RU switch optimized for ultra-low latency. It is not a modular chassis and lacks the specified fabric architecture and scale.

1. Arista 7500E Series Data Sheet: In the "Product Overview," the 7500E is described as a "modular chassis" for "high density data centers." The "Arista EOS" section on page 2 explicitly mentions the "Virtual Output Queue (VOQ) architecture" that "eliminates head-of-line (HOL) blocking."

2. Arista 7500R Series Data Sheet: This document details line cards compatible with the 7500E chassis. The "Product Overview" on page 1 highlights the VOQ architecture. The line card table on page 2 lists modules like the 7500R2-36CQ, which provides 3.6 Tbps of forwarding, demonstrating the platform's ability to meet the high-capacity requirement.

3. Arista 7300X3 and 7320X Series Data Sheet: The line card specifications table on page 2 shows the highest capacity line card, the 7320X-32C, offering "6.4Tbps" of full-duplex throughput, which corresponds to 3.2 Tbps in one direction, falling short of the 3.84 Tbps requirement.

4. Arista Networks, EOS Central - VOQ and Virtual Output Queues: This official documentation explains, "Arista’s 7500, 7300 and 7280R platforms are all VOQ systems... In a VOQ system, there is no head of line blocking." This confirms that both 7500 and 7300 series use VOQ, making the performance per slot the key differentiator in the question.

Arista VMTracer is a feature designed for virtualized data centers that requires the 'V' (Virtualization) license for activation, confirming it is not a free feature. Its functionality allows the switch to communicate with virtualization management systems like VMware vCenter. While VMTracer has broad support across Arista's data center switching platforms and is explicitly supported on vEOS instances, it is not a universal feature across all Arista hardware. For example, it is generally not available on campus-focused switch series. Therefore, its support is limited to certain Arista switches, making both statements A and C correct.

B. VMTracer is not free; it requires the purchase of the Arista 'V' (Virtualization) license to enable its functionality.

D. VMTracer is explicitly supported on vEOS instances, as stated in official Arista configuration guides for use in virtualized environments.

1. Arista Networks, EOS Licensing Philosophy and Guide (2023): The guide details the features included with different EOS software licenses. The 'V' (Virtualization) license section explicitly lists "VM Tracer" as a licensed feature. (Reference: See section on "Virtualization License ('V')").

2. Arista Networks, VM Tracer Configuration Guide, EOS-4.28.0F: This document states, "VM Tracer is supported on all Arista modular and fixed-configuration switches and routers, and on vEOS instances." This confirms support for vEOS (disproving D) and implies the feature is intended for specific classes of devices (routers and modular/fixed switches), not every product. (Reference: "Platform Support" section).

3. Arista Networks, 7050X3 Series Data Sheet: This data sheet for a data center switch lists "VMTracer" under the "Virtualization" software features, confirming its availability on this platform. (Reference: Software Features table).

4. Arista Networks, 720XP Series Data Sheet: This data sheet for a campus access switch does not list VMTracer in its software features, demonstrating that the feature is only supported on "certain" Arista switches and not universally. (Reference: Software Features table).

The Multi-Switch CLI feature in Arista EOS utilizes a concept called "switch-groups" to manage multiple devices from a single point. An administrator can define a named group consisting of several switches. Once a switch-group is created, non-interactive commands (e.g., show commands, configuration changes) can be sent to all switches within that group simultaneously. This capability is central to the Multi-Switch CLI feature, enabling efficient and consistent management across a fleet of devices.

A. groups: This term is too generic. While a "switch-group" is a type of group, the specific feature name within the Multi-Switch CLI context is "switch-groups."

C. chat-rooms: This term is not associated with Arista EOS CLI management. It implies a real-time communication or messaging function, which is unrelated to command execution.

D. chat-groups: Similar to "chat-rooms," this is not a valid Arista EOS feature for managing multiple switches via the CLI.

1. Arista EOS Configuration Guide: In the section detailing Multi-Switch CLI, the guide explicitly states, "Multi-switch CLI allows you to configure and manage multiple switches from a single CLI session. You can create switch groups to send non-interactive commands to multiple switches at once."

Source: Arista EOS 4.27.1F Configuration Guide, Chapter 10: Management Services, Section: "Multi-Switch CLI," Page 225.

2. Arista EOS Central - Multi-Switch CLI: The official documentation on Arista's website describes the feature and its components. It details the creation and usage of switch-group for command distribution.

Source: Arista Networks, EOS Central, "Multi-Switch CLI," section on "Switch Groups." (e.g., https://www.arista.com/en/um-eos/eos-multi-switch-cli) The documentation outlines the command syntax switch-group for creating these entities.

The Extensible Messaging and Presence Protocol (XMPP) management interface on Arista EOS is disabled by default. This is consistent with security best practices for network devices, which advocate for a minimal attack surface upon initial deployment. An administrator must explicitly enter the management xmpp configuration mode, define the required connection parameters (such as server, Jabber ID, and password), and then explicitly enable the service using the no shutdown command within that configuration context.

The statement "True" is incorrect. Enabling a management protocol like XMPP by default would expose the device to unnecessary security risks without explicit configuration and intent from a network administrator. Arista EOS follows a secure-by-default principle where non-essential management services must be deliberately enabled.

1. Arista EOS Configuration Guide: In the section detailing the configuration of management interfaces, the guide explicitly states that the XMPP feature is not active by default. The configuration process requires entering a specific configuration mode and enabling the service.

Source: Arista EOS 4.28.0F Configuration Guide

Reference: Chapter 61: XMPP, Section 61.2 "Configuring XMPP". The section begins with the steps to enter the management xmpp configuration mode, which implies the feature is not pre-configured or active. The inclusion of the no shutdown command in the configuration example further confirms that the service is administratively disabled by default.

2. Arista Design and Deployment Guides: Security and management best practice documents emphasize enabling only necessary services.

Source: Arista Design Guide - Switch Hardening

Reference: Section "Control Plane Hardening". This section typically advises disabling all unused management interfaces and protocols to reduce the device's attack surface. The default state of XMPP being disabled aligns directly with this fundamental security principle.

Arista's Latency Analyzer (LANZ) is a feature designed to detect and report microbursts and network congestion by monitoring queue lengths. When a queue's length surpasses a configured high threshold, LANZ generates a "Start" record, signaling the beginning of a congestion event. While the queue remains congested (above the high threshold), periodic "Update" records are sent, providing details on the ongoing event, such as the maximum queue length observed. Once the queue length drops below a configured low threshold, an "End" record is generated, marking the conclusion of the congestion event. These three record types—Start, Update, and End—provide a complete lifecycle view of each congestion incident.

A. The term "Stop" is incorrect. LANZ uses "End" to signify that the queue length has fallen below the low threshold and the congestion event has concluded.

C. The term "Begin" is incorrect. The official terminology used by Arista LANZ for initiating a congestion record is "Start".

D. Both "Begin" and "Stop" are incorrect terms. The correct terminology used in LANZ event reporting is "Start" and "End" respectively.

1. Arista Networks. (2021). EOS 4.25.1F Configuration Guide. Section 41.2.1, "LANZ Operation", Page 911. "When a queue length exceeds its configured high threshold, LANZ generates a congestion start record... While the queue length remains above the high threshold, LANZ generates congestion update records... When the queue length drops below the configured low threshold, LANZ generates a congestion end record."

2. Arista Networks. (2013). Arista Latency Analyzer (LANZ) White Paper. Page 3, "How LANZ Works". "When a queue length exceeds its configured high threshold, LANZ generates a congestion start record... While the queue length remains above the high threshold, LANZ generates congestion update records... When the queue length drops below the configured low threshold, LANZ generates a congestion end record."

According to Arista EOS documentation, when a scheduled job is created, the system automatically generates a directory to store the output of the commands executed by that job. This directory is created inside the /mnt/flash/schedule/ path. The name of this output directory precisely matches the name assigned to the job during its configuration. EOS job names are case-sensitive, so a job created with the name "Colleen-Job" will have its output stored in a directory named "Colleen-Job", preserving the capitalization.

A. This is incorrect because EOS preserves the case of the job name for the directory. It does not convert the name to lowercase.

B. This path is incorrect as it omits the required /schedule/ parent directory where all scheduled job outputs are placed by default.

C. This is an alias for /mnt/flash/Colleen-Job and is incorrect because it also omits the mandatory /schedule/ parent directory.

1. Arista EOS Configuration Guide: In the "Scheduled Jobs" section, it is stated: "The job name is case-sensitive. When a schedule is created, the switch creates a directory named for the job in /mnt/flash/schedule. The output of the commands in the job is placed in this directory." (Reference: Arista EOS 4.27.2F Configuration Guide, Chapter 48: System Management, Section: Scheduled Jobs).

Zero Touch Provisioning (ZTP) is a foundational feature of the Arista Extensible Operating System (EOS), not a feature exclusive to a specific hardware series. All Arista switches running EOS, including the 7050, 7280E, 7300, and 7500E series, ship from the factory with ZTP enabled by default. This core functionality allows any of these devices to automatically discover a provisioning server, download a boot script, update its EOS image, and apply a device-specific configuration file upon initial power-on. This process eliminates the need for manual console-based configuration for any Arista switch. Therefore, all the listed options are correct.

No options are incorrect. ZTP is a universal feature across all Arista switch platforms running EOS, making all listed series valid answers.

1. Arista Networks, EOS 4.31.1F Configuration Guide: In the "Zero Touch Provisioning" chapter, the overview states, "Zero Touch Provisioning (ZTP) is a process that configures Arista switches automatically without user intervention." The guide does not specify any hardware limitations, indicating its universal applicability across EOS devices.

2. Arista Networks, Design and Implementation Guides, "Zero Touch Provisioning (ZTP)": This official design guide explicitly states in its introduction, "All Arista switches running EOS ship from the factory in ZTP mode." This confirms the feature is present on all platforms, not just a select few.

3. Arista Networks, "Arista 7050X3 Series Datasheet": Under the "Extensible Operating System" section, "Zero Touch Provisioning (ZTP)" is listed as a key feature for provisioning and configuration, confirming its support on the 7050 series. Similar statements are found in the datasheets for the 7280, 7300, and 7500 series switches.

The correct command to specify the boot image for the next reload on an Arista switch is boot system. This command requires the full path to the software image file. The path must include the filesystem where the image is stored (typically flash:), a colon and a forward slash (:/), followed by the exact filename of the EOS image (.swi file). Option C provides the complete and syntactically correct command to set the boot image to EOS-4.15.1F.swi located in the flash memory.

A. This option specifies an incorrect filename (EOS-4.15.1.swi), which is missing the "F" from the version 4.15.1F stated in the question.

B. This command is incomplete as it omits the mandatory filesystem path (flash:/), preventing the switch from locating the specified image file.

D. This command uses incorrect syntax. A space is used between the filesystem (flash) and the filename, whereas the correct syntax requires :/.

1. Arista Networks, EOS User Manual, Release 4.23.0F: In the "Command-Line Interface" section, under "Configuration Commands," the boot system command is detailed. The syntax is shown as boot system flash:/.swi. This confirms the requirement for the flash:/ prefix and the full image name. (Reference: Arista EOS User Manual, specific examples in software upgrade sections).

2. Arista Networks, EOS 4.21.1F System Management Configuration Guide: In the chapter on "Managing System Files," the section "Specifying the Boot Image" explicitly documents the command. An example provided is switch(config)# boot system flash:/EOS-4.21.1F.swi, which directly validates the format used in the correct answer. (Reference: Document ID: EOS-4.21.1F-SysMgmt, Page 15, "Specifying the Boot Image").

When one of two MLAG peer switches is reloaded, all its physical links go down, including the member links of any Port-Channels connected to dual-homed hosts. The remaining active MLAG peer detects the failure via the peer-link heartbeat and continues to forward traffic. The dual-homed host, using LACP, detects the link failure to the rebooting switch and redirects all traffic to the remaining active link connected to the healthy peer. While this prevents a complete network outage for the host, its total available bandwidth through the MLAG domain is halved until the rebooting switch comes back online and its MLAG ports are restored.

B. The peer switch also reboots to ensure network stability.

This is incorrect as it would defeat the primary purpose of MLAG, which is to provide high availability and redundancy by surviving a single switch failure.

C. The peer switch sends out gratuitous BPDUs to let the network know that it has assumed the root-bridge role.

This is a possible secondary effect related to Spanning Tree Protocol (STP) if the rebooting switch was the root, but it is not the most direct or guaranteed result. The primary impact is on the data path capacity.

D. Nothing bad ever happens when MLAG is enabled!

This is incorrect. While MLAG provides resilience against complete outages, the temporary loss of 50% of the available bandwidth is a significant, albeit managed, negative event.

1. Arista Networks, EOS Configuration Guide, Release 4.28.0F: In the "MLAG Concepts" section, under "Failure Scenarios," the documentation describes the behavior during a peer switch failure. It states, "If an MLAG peer fails, the remaining peer continues to forward traffic. From the perspective of the attached device, one of the links in its LAG went down, and it continues to forward traffic on the remaining link(s)." This directly supports the loss of a link and the continuation of traffic on the other, which implies a reduction in capacity.

2. Arista Networks, MLAG - High Availability: This design guide explains the fundamental principle of MLAG. In the section on "MLAG Failure Scenarios," it details that upon the failure of one peer, "traffic from the access device is forwarded to the remaining active MLAG peer." This confirms that connectivity is maintained but through fewer links, hence reduced capacity. (Reference: Arista.com Design and Deployment Guides).

3. Arista Networks, EOS Central (Legacy Documentation Archive), MLAG Basic Configuration: Older configuration guides for versions similar to 4.14 consistently describe MLAG's role in providing hitless forwarding during the failure or upgrade of a single peer. The core mechanism relies on the remaining switch handling all traffic, which inherently means the paths to the failed switch are unavailable. (Reference: Arista EOS Central archives for MLAG).

In Arista's Extensible Operating System (EOS), extensions must be explicitly configured to load automatically upon system boot. The command copy installed-extensions boot-extensions achieves this by taking the list of all currently installed extensions (represented by the keyword installed-extensions) and writing this list to a special configuration file named boot-extensions. During the boot sequence, EOS reads the boot-extensions file and loads each extension listed within it, ensuring their persistence across reboots.

A. install extensions permanent

This is not a valid EOS command. The install extension command does not have a permanent keyword; persistence is managed separately.

B. boot installed-extensions

This is not a valid EOS command. The boot command is used to configure the system's primary boot image (boot system ...), not for managing extensions.

C. copy extensions: boot-extensions:

This command is syntactically incorrect. extensions: refers to the directory, not the list of installed extensions. The correct keyword is installed-extensions (without a colon).

1. Arista EOS Configuration Guide (Version 4.31.1F): In the "Extensions" section, under the subsection "Making an Extension Persistent," the guide explicitly states: "To make all currently installed extensions persistent, copy the list of installed extensions to the boot-extensions file." It then provides the exact command: switch#copy installed-extensions boot-extensions. (Section 11.10.3)

2. Arista Networks Documentation - Managing EOS Extensions: This official article details the lifecycle of extensions. In the section "Making an Extension Persistent," it states: "To ensure that all currently installed extensions are loaded on the next reboot, copy the list of installed extensions to the boot-extensions file: copy installed-extensions boot-extensions". (Arista EOS Central, Document ID: TOI-122)