4A0-D01 Nokia Data Center Fabric Fundamentals Exam Question and Answers

Comprehensive and Detailed Explanation with Exact Extracts:

Exhibit Analysis:

The configuration defines a log file named bgp-log (not a buffer) under system logging.

It includes messages from subsystems bgp and netinst (network-instance).

SR Linux Logging Command Syntax:

show system logging file  is the operational command to display contents of a log file.

show system logging buffer  is used for memory buffers, not files.

info commands display configuration, not log contents.

Verification from Documentation:Extract from Nokia SR Linux CLI Guide (Section: Logging Commands):

"Use show system logging file  to display the current contents of a configured log file. For example:

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A:dc-leaf-1# show system logging file bgp-log

This outputs the log entries stored in the specified file."

Extract from Nokia SR Linux Configuration Guide (Section: Log Files):

"Log files are persistent entities stored in /var/log/srlinux/. Their contents are viewed exclusively via show system logging file, not info or buffer commands."

Why Other Options Are Incorrect:

A: buffer references in-memory logs, not persistent files.

C/D: info displays configuration (e.g., info system logging shows the snippet in the exhibit), not log contents.

Comprehensive and Detailed Explanation:

LLDP (Link Layer Discovery Protocol) frames are link-local multicast frames sent to the destination MAC address 01:80:C2:00:00:0E. They are not routed (eliminating Option D) and operate independently of VRF tables (eliminating Options A/B). SR Linux floods LLDP frames periodically on all active interfaces.

Exact Extract:

*"LLDP frames are transmitted periodically as untagged Ethernet frames to the nearest-bridge multicast address (01:80:C2:00:00:0E). They are flooded locally and not forwarded beyond the local subnet."*

Comprehensive and Detailed Explanation From Exact Extract:

The SR Linux Application Manager (app_mgr):

Option A is TRUE: Monitors application health and restarts failed processes.

"The Application Manager monitors the status of all running applications and triggers recovery actions if failures occur."

— SR Linux System Management Guide, "Application Manager"

Option B is TRUE: Manages both Nokia-provided and user-added containerized applications.

"app_mgr manages the lifecycle of all applications, whether preinstalled by Nokia or custom-developed by users."

— SR Linux DevOps Guide, "Custom Application Deployment"

Option C is TRUE: Parses application manifests and launches applications.

"The Application Manager reads manifest files (including configuration) and starts applications accordingly."

— SR Linux Configuration Fundamentals, "Application Initialization"

Option D is FALSE: Translation of YANG to protobuf is handled by the Management Server (mgmt_server), not app_mgr.

"The Management Server (mgmt_server) compiles YANG models into protobuf schemas for the Interface Database (IDB). The Application Manager does not handle model translation."

— SR Linux Architecture White Paper, "Data Modeling Components"

Comprehensive and Detailed Explanation with Exact Extracts:

Exhibit Analysis:

The output shows real-time ICMP packet captures (echo requests/replies) with detailed metadata (interface, source/destination IP, protocol, size, TTL).

The command tools system traffic-monitor protocol icmp confirms this is a tcpdump-like utility (packet capture tool), not a log file.

Mechanism for Packet Capture:

Capture-filter ACL is required to copy data-plane packets (like ICMP between hosts) to the CPM for analysis by traffic-monitor.

Extract from Nokia SR Linux Troubleshooting Guide:

"traffic-monitor is a CPM-based packet capture tool. To capture data-plane traffic (e.g., host-to-host ICMP), a capture-filter ACL must be applied to interfaces to copy packets to the CPM."

Extract from Nokia SR Linux ACL Configuration Guide:

"Unlike cpm-filter (for control-plane protection), capture-filter ACLs are designed to mirror user traffic to the CPM for debugging via traffic-monitor."

Why Other Options Are False:

A: Generic "ACL filter" is ambiguous. Only capture-filter ACLs copy data-plane traffic to the CPM for traffic-monitor.

C: cpm-filter policer rate-limits control-plane traffic (e.g., ICMP to the router), not host-to-host ICMP. It does not enable packet capture.

D: cpm-filter handles control-plane traffic destined for the router (e.g., ICMP to router IPs), not transit traffic. It does not support traffic-monitor.

Comprehensive and Detailed Explanation with Exact Extracts:

Option A is FALSE: The provisioning script URL is not defined in the TLS profile. It is provided via DHCP (option 239) or DNS.

Extract from Nokia SR Linux ZTP Guide:

"The DHCP server supplies the URL to the provisioning script (via option 239). TLS profiles secure script/image downloads but do not define the script location."

Options B, C, and D are TRUE:

B: ZTP is managed by the ztp application in the management container.

C: DHCP provides initial IP/gateway.

D: ZTP requires no manual configuration.

Extract from Nokia SR Linux Installation Guide:

"The ZTP application automates deployment. It uses DHCP for network parameters and fetches scripts to make the device operational without pre-configuration."

Comprehensive and Detailed Explanation with Exact Extracts:

Option A (TRUE): Type 1 routes enable multi-homing functions.

Extract from Nokia EVPN Multi-Homing Guide:

"Type 1 Ethernet A-D routes signal reachability for an Ethernet Segment (ES) and enable fast convergence/aliasing in multi-homing."

Option B (TRUE): Type 4 routes facilitate DF election.

Extract from Nokia EVPN Fundamentals Guide:

"Type 4 Ethernet Segment routes advertise ESI and VTEP IP to peers for Designated Forwarder (DF) election, which prevents BUM traffic loops."

Option C (FALSE): The ESI is globally unique, not locally significant.

Extract from Nokia SR Linux Configuration Guide (Section: EVPN ESI):

"The ESI must be unique network-wide and consistently configured on all leafs attached to the same multi-homed device. It is not locally significant."

Option D (TRUE): An ES defines the host connectivity model.

Extract from Nokia EVPN Multi-Homing Guide:

"An Ethernet Segment (ES) is a set of links connecting a single host (e.g., server) to one or more leafs for redundancy/load balancing."

Comprehensive and Detailed Explanation From Exact Extract:

Option A: TRUE – Fabric intent is declaratively defined in YAML.

"FSS uses YAML-based declarative intent to define and manage fabric configurations."

— Nokia Fabric Services System User Guide, "Intent-Based Fabric"

Option B: FALSE – The Digital Sandbox is for pre-deployment validation, not performance monitoring.

"The Digital Sandbox simulates configurations for validation before deployment. Performance monitoring is handled by telemetry analytics, not the sandbox."

— Nokia FSS Deployment Guide, "Digital Sandbox"

Option C: TRUE – Telemetry is contextualized with intent.

"Telemetry data is correlated with fabric intent, providing context-aware insights."

— Nokia FSS Operations Guide, "Telemetry and Analytics"

Option D: TRUE – FSS is cloud-native for flexible integration.

"FSS’s cloud-native microservices architecture simplifies integration with customer ecosystems."

— Nokia FSS Architecture White Paper, "Cloud-Native Design"

Conclusion: Option B misrepresents the Digital Sandbox’s purpose.