4A0-D01 Nokia Data Center Fabric Fundamentals Exam Free Practice Exam Questions (2025 Updated)

Comprehensive and Detailed Explanation with Exact Extracts:

Options A, B, and C describe standard leaf-spine eBGP operation:

Leaf routers peer with spines (eBGP), advertising local prefixes (Option C).

Spines learn prefixes from leaves (Option B) and re-advertise them to other leaves (Option A).

Extract from Nokia Data Center Fabric Guide (Section: eBGP Leaf-Spine):

"Leaf routers establish eBGP sessions with spine routers, advertising prefixes of locally attached endpoints. Spine routers propagate these prefixes to all other leaf routers, providing full connectivity."

Option D is FALSE: Leaf routers do not peer directly with each other in standard designs. They communicate via spines.

Extract from Nokia Data Center Fabric Guide (Section: Routing Design):

"Leaf routers never establish direct eBGP sessions with other leaf routers. All inter-leaf communication occurs via spine routers, which act as route reflectors or forwarding hubs."

Comprehensive and Detailed Explanation with Exact Extracts:

Option A is FALSE: Next-hop groups support indirect next-hops (non-local IPs requiring recursive lookup).

Extract from Nokia SR Linux Configuration Guide (Section: Next-Hop Groups):

"The next-hop can be a directly attached IP address or an indirect next-hop (e.g., a router IP not on a directly connected subnet)."

Option B is TRUE: Next-hop groups are reusable objects referenced by multiple static routes.

Extract from Nokia SR Linux Configuration Guide (Section: Next-Hop Groups):

"A single next-hop group can be referenced by multiple static routes, simplifying configuration for shared forwarding behavior."

Option C is FALSE: Blackhole next-hop groups silently drop traffic by default. ICMP unreachable messages require explicit configuration.

Extract from Nokia SR Linux Configuration Guide (Section: Blackhole Routes):

"When blackhole is configured, traffic is discarded without sending ICMP unreachable messages unless send-blackhole-icmp true is explicitly set."

Option D is FALSE: Next-hop groups support ECMP with multiple next-hops.

Extract from Nokia SR Linux Fundamentals Guide (Section: Next-Hop Groups):

"A next-hop group can define multiple next-hops for Equal-Cost Multi-Path (ECMP) load balancing."

Comprehensive and Detailed Explanation From Exact Extract:

Option A: TRUE – IP-VRF is defined as a Layer 3 routing instance.

"An IP-VRF network instance provides Layer 3 routing services, isolating tenant routing domains."

— SR Linux Network Instance Guide, "IP-VRF Fundamentals"

Option B: TRUE – Forwarding decisions are IP-based.

"IP-VRF forwards packets based on destination IP address using its dedicated routing table."

— SR Linux Routing Guide, "IP-VRF Forwarding"

Option C: TRUE – Each IP-VRF has an independent route table.

"Each IP-VRF maintains a separate route table for complete routing isolation."

— SR Linux Configuration Guide, "Network Instances"

Option D: FALSE – Multiple servers in the same subnet belong to a MAC-VRF (L2 domain), not IP-VRF. IP-VRF handles inter-subnet routing.

"Servers in the same IP subnet must reside in the same MAC-VRF (Layer 2 bridge domain). The IP-VRF provides routing between subnets."

— *SR Linux EVPN Services Guide, "L2/L3 Integration"*

Conclusion: Option D is false because same-subnet devices are grouped in MAC-VRF.

Comprehensive and Detailed Explanation with Exact Extracts:

Option B (CPM-filter ACL) is CORRECT:

The CPM-filter ACL is explicitly designed to match control-plane traffic and copy it to the CPM (Control/Management Plane). It is instantiated in hardware on all line cards.

Extract from Nokia SR Linux Security Guide (Section: Control Plane Protection):

"The cpm-filter ACL is instantiated on every line card to identify packets destined for the CPM (e.g., routing protocols, ICMP). Matched packets are copied to the CPM while data-plane traffic is forwarded normally."

Other Options are INCORRECT:

A: Capture-filter ACL is for packet mirroring (e.g., SPAN), not CPM copying.

C/D: Ingress/Egress ACLs filter user traffic and are not specific to CPM-bound packets.

Extract from Nokia SR Linux ACL Configuration Guide:

"Only cpm-filter ACLs are globally applied across line cards for CPM protection. Interface ACLs (ingress/egress) operate locally and do not copy packets to the CPM."

The "baseline diff" command is used to compare the candidate configuration against the baseline datastore to see changes or conflicts, especially when multiple users are involved or to verify differences. It does not indicate that the user is unable to commit changes.

Comprehensive and Detailed Explanation with Exact Extracts:

Options A, B, and C are part of ZTP autoboot:

A: DHCP assigns IP/gateway.

B/C: Scripts download images/RPMs from servers (HTTP/FTP).

Extract from Nokia SR Linux ZTP Guide:

"Autoboot triggers DHCP discovery for IP/gateway. The device then fetches a provisioning script (via DHCP/DNS) that downloads RPMs/images from HTTP/FTP servers."

Option D is NOT part of ZTP autoboot:

Fabric Services System (FSS) and its digital sandbox are separate tools for lifecycle management. ZTP does not auto-deploy them.

Extract from Nokia FSS Deployment Guide:

"FSS deployment requires manual setup or orchestration tools. The digital sandbox is not automatically deployed via ZTP autoboot."

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 with Exact Extracts:

Option A (TRUE): VTEPs (VXLAN Tunnel Endpoints) are deployed flexibly.

Extract from Nokia VXLAN Configuration Guide:

"VTEPs can reside on hypervisors (virtual switches), leaf routers (network-based overlays), or data center gateways (for inter-fabric connectivity)."

Option B (TRUE): EVPN is the control plane for VXLAN.

Extract from Nokia EVPN-VXLAN Integration Guide:

"EVPN route types (e.g., Type 2 MAC/IP, Type 3 Inclusive Multicast) are exchanged between VTEPs to establish forwarding semantics for the VXLAN overlay."

Option C (FALSE): The VNI (VXLAN Network Identifier) is not automatically assigned per VTEP.

Extract from Nokia SR Linux Fundamentals Guide (Section: VXLAN):

"The VNI is a manually configured 24-bit segment ID per Layer 2 domain (or VRF for L3VNI). A single VTEP handles multiple VNIs simultaneously. VTEPs are identified by IP addresses, not VNIs."

Option D (TRUE): VXLAN enables L2 extension over IP underlays.

Extract from Nokia Data Center Design Guide:

"VXLAN encapsulation provides Layer 2 connectivity between workloads (e.g., VMs, containers) across a routed underlay network."

Comprehensive and Detailed Explanation with Exact Extracts:

Option A (VNI is included): The IMET route explicitly carries the VNI (as the Ethernet Tag ID) to identify the Layer 2 domain.

Extract from Nokia EVPN-VXLAN Guide (Section: IMET Route):

"The IMET (Type 3) route includes the VNI (Ethernet Tag ID) to signal membership in a specific broadcast domain."

Option B (Flooding list is NOT included): The IMET route does not contain a flooding list. Each VTEP independently builds the flooding list by aggregating all received IMET routes for the same VNI (e.g., VTEP1 uses IMET routes from VTEP2 and VTEP3 to build its list).

Extract from Nokia SR Linux Fundamentals Guide (Section: EVPN BUM Handling):

"The flooding list for a VNI is dynamically constructed by each VTEP based on received IMET routes. The IMET route itself only advertises the sender's VTEP IP and VNI, not a pre-defined list of peers."

Option C (Route Distinguisher is included): The IMET route includes the MAC-VRF's Route Distinguisher (RD) to ensure uniqueness in the control plane.

Extract from Nokia EVPN Configuration Guide:

"Every IMET route carries the MAC-VRF's RD to distinguish overlapping VNIs across different network instances."

Option D (VTEP IP is included): The IMET route advertises the VTEP's IP address (via the PMSI Tunnel attribute) to establish the BUM traffic tunnel endpoint.

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

"The IMET route includes the originating VTEP's IP address in the PMSI Tunnel field. This IP is used as the destination for VXLAN-encapsulated BUM traffic."

Exhibit Analysis:

The IMET routes (advertised by VTEP1, VTEP2, VTEP3) are shown.

Each VTEP's locally configured flooding list (e.g., VTEP1: [VTEP2, VTEP3]) is derived from received IMET routes, not embedded in the IMET route itself.