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

Comprehensive and Detailed Explanation with Exact Extracts:

Option A (Valid):  Log sources can be defined using Linux syslog facilities (e.g.,  local6 ) and priorities.

Extract from Nokia SR Linux Configuration Guide:

"Log sources are identified using  Linux facilities (e.g.,  kernel ,  local6 ) and priorities  (e.g.,  info ,  error )."

Option B (Valid):  The console is a valid source for log messages (e.g., kernel boot logs).

Extract from Nokia SR Linux Fundamentals Guide:

" Console output  is treated as a log source, particularly for kernel and early-boot messages captured before system services initialize."

Option C (Valid):  SR Linux subsystems (e.g.,  bgp ,  system ) generate logs with specific priorities.

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

"Logs generated by  SR Linux subsystems  (e.g.,  network-instance ,  interface ) can be filtered by subsystem name and  priority ."

Option D (Invalid):  "Syslog filter" is  not a source —it is a configuration mechanism.

Extract from Nokia SR Linux System Management Guide:

" Filters  ( /system logging filter ) are applied to log  sources  (facilities/subsystems) to select messages for destinations. Filters themselves  do not generate logs ."

Comprehensive and Detailed Explanation:

Nokia’s Fabric Services System (FSS) employs an  intent-driven approach  where the fabric intent is defined in a  YAML file . This file specifies the  desired state  of the data center fabric, including topology, services, and policies. FSS translates this declarative intent into device-specific configurations.

Exact Extract :

"Fabric Services System uses intent-based YAML templates to define the fabric’s target state. The system automates configuration generation and deployment, ensuring consistency across the fabric."

Comprehensive and Detailed Explanation with Exact Extracts:

Option A (TRUE):  SR Linux uses  local6  as the default syslog facility.

Extract from Nokia SR Linux System Management Guide:

"System logs are emitted with the  syslog facility  local6  by default, allowing integration with standard Linux syslog utilities."

Option B (TRUE):  SR Linux supports local encrypted log storage.

Extract from Nokia SR Linux Security Guide:

"Log files stored locally can be  encrypted  using AES-256 to ensure confidentiality and integrity of audit trails."

Option C (TRUE):  Log filters are fully supported for message selection.

Extract from Nokia SR Linux Configuration Guide (Section: Logging):

" Filters  can be applied to log messages based on severity, subsystem, or content, enabling granular control over log destinations."

Option D (FALSE):  SR Linux uses  systemd-journald , not rsyslog, for log management.

*Extract from Nokia SR Linux Release Notes (v21.11+):*

"SR Linux logging configurations are  not  translated to  /etc/rsyslog.conf . The system relies on  systemd-journald  for log collection and storage, with configurations managed via SR Linux CLI and stored in  /etc/journald.conf ."

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 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 < filename >  is the operational command to  display contents  of a log file.

show system logging buffer < name >  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 < filename >  to display the current contents of a configured log file. For example:

text

Copy

Download

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 From Exact Extract:

Option A :  TRUE  –  state  mode shows configuration + operational state.

"The  state  command provides a unified view of configuration and real-time operational data."

—  SR Linux CLI User Guide, "State Mode"

Option B :  TRUE  –  show  mode uses predefined templates.

" show  commands use structured report templates for consistent operational data display."

—  SR Linux CLI User Guide, "Show Commands"

Option C :  TRUE  –  running  mode is for configuration changes.

"Configuration edits occur in  running  mode, which modifies the candidate configuration."

—  SR Linux Configuration Fundamentals, "CLI Modes"

Option D :  FALSE  –  use  (not  enter ) switches modes .

"Mode transitions use the  use  command (e.g.,  use state ).  enter  navigates hierarchical paths within a mode."

—  SR Linux CLI User Guide, "Mode Navigation"