Data Centre Network Workspace

Network Insight Data Centre Networking

Data Centre Network Workspace

Explore how modern data-centre networks are designed, connected and operated. Learn through network architecture, traffic paths, routing, overlays and practical troubleshooting — in one connected learning environment.

Leaf–Spine Fabrics BGP Underlay VXLAN / EVPN Fabric Troubleshooting

Interactive learning environment

YOUR LEARNING ROUTE

Navigate the Data Centre Network Workspace

Move from understanding the fabric to tracing traffic, diagnosing failures and evaluating network changes. Follow the five stages in sequence, or jump directly to a topic you want to investigate.

Choose your learning stage

5 stages · Guided learning

Your learning route is a guide through the activities on this page. Assessment results are handled by the individual knowledge-check widget.

Choose a learning mode

Select a topic to explore its purpose and learning objectives.

04 learning modes

Selected learning mode

Data Centre Architecture

Understand the leaf-spine fabric, the roles of leaf and spine switches, server connectivity, and how the physical network supports communication across the data centre.

Fabric Explorer / 01

Explore the network fabric

Select a switch, server or connection to inspect its role. Activate traffic-path mode to explore an illustrative journey through the leaf-spine architecture.

Educational topology

Fabric connection Illustrative traffic path Selected device

Leaf switch

Leaf 1

A leaf switch connects endpoints to the fabric and forwards traffic toward other destinations.

Access layer Server connectivity

Ready. Select a device or connection to explore the topology. This is an illustrative model, not a live network simulation.

Fabric Explorer / 02

Traffic Investigation Lab

Follow traffic between two endpoints and investigate each stage of the journey. Change the source or destination to compare local communication with traffic that crosses the fabric.

Source endpoint Destination endpoint

Traffic journey

Server 1 → Server 2

Step 1 of 5 · Select Start investigation to begin.

Investigation step 1

Source endpoint

Begin with the source server. Confirm the endpoint's addressing and determine which leaf switch it uses to enter the fabric.

Engineering checks

Check the source IP address and subnet.
Confirm the server's default gateway where applicable.
Identify the directly connected leaf switch.

Concept to remember

Troubleshooting is easier when you start at the endpoint and follow the traffic toward its destination.

Ready to investigate the selected endpoints.

This is a teaching model, not a packet capture or live network simulation. The selected route illustrates a possible forwarding journey; actual paths depend on routing, forwarding state, policies, topology and configuration.

Data Center Network Workspace · Lab 05

Fabric Failure Lab

A traffic path has failed. Choose a fault scenario, inspect the fabric, and work through the evidence before deciding what to investigate next.

Select a failure scenario

Illustrative leaf-spine fabric Fabric healthy

Leaf layer Spine layer Fault location

Your investigation

Select the checks you would perform. Then submit your diagnostic plan.

Inspect physical and interface status Check link state, errors, and interface counters. Verify alternate fabric paths Determine whether another spine path is available. Check endpoint and attachment state Confirm the destination is powered, connected, and reachable. Inspect route and forwarding state Check whether the expected destination entry is present. Compare the failure scope Test other destinations and paths to identify what is affected.

Start with the evidence. Select checks that help isolate the fault rather than guessing at the cause.

Incident report

Scenario 1 · Connectivity

One fabric link is down

Traffic between two endpoints is failing or experiencing reduced path availability. One leaf-to-spine connection is reported down.

Observed symptom An interface reports down; the fabric may still have an alternate path.

Key question Is this a single-link fault, and can traffic use another available path?

Engineering guidance

Recommended approach

Establish the fault boundary

Confirm the reported interface state, inspect counters and logs, then verify whether the alternate leaf-to-spine path is operational. Do not assume redundancy guarantees uninterrupted service; validate the actual forwarding path.

Learning objective: distinguish a failed component from the wider impact on the fabric.

Educational simulation · No live switches, telemetry, or packet captures are accessed.

Data Center Network Workspace · Lab 06

Fabric Health Dashboard

Assess link availability, device status, path redundancy, and simulated incidents. Change the fabric condition to see how a fault affects the overall health picture.

Fabric links up

4/4

All uplinks available

Devices operational

4/4

Leaf and spine switches

Path redundancy

2 paths

Two fabric paths available

Forwarding state

Ready

Illustrative destination entry present

Fabric topology

Operational Degraded Failed

This simplified fabric has two leaf switches and two spine switches. The metrics below are simulated teaching values, not production telemetry.

Link status

Connection	State	Role
Leaf 1 – Spine 1	Up	Uplink
Leaf 1 – Spine 2	Up	Uplink
Leaf 2 – Spine 1	Up	Uplink
Leaf 2 – Spine 2	Up	Uplink

Active incidents

No active simulated incidents

Clear

The current example fabric is healthy. Select a fault mode to see a corresponding incident.

Engineering interpretation

Healthy fabric does not mean every service is proven healthy

Operational links and devices are a useful starting point. Validate the actual destination, route, and application path before declaring end-to-end service healthy.

Next diagnostic action

Validate a representative traffic path

Recommended

Test endpoint reachability and confirm the expected route and forwarding entry on the relevant devices.

No check run yet. Choose a scenario and run a health check.

Data Center Network Workspace · Lab 07

Network Change Simulator

Evaluate a proposed fabric change before implementation. Review the baseline, identify risk, complete pre-change checks, and make an evidence-based go/no-go decision.

1 Review

2 Assess

3 Decide

Proposed change

Temporarily remove one uplink from service for maintenance while preserving a possible alternate path.

Illustrative baseline

Active uplinks4 / 4

Fabric devices4

Inter-leaf paths2

Pre-change checklist

Baseline capturedRecord current interface, route, and service status. Redundancy verifiedConfirm the remaining path is operational and suitable. Rollback plan preparedDefine the recovery action and success criteria. Change window approvedConfirm authorization, timing, and communication. Post-change validation definedSpecify the tests that will prove service health.

Select a proposed change, review the checklist, and assess the risk before deciding whether to proceed.

Change impact assessment

Single uplink maintenance

Moderate

One link is temporarily removed from service. The other uplinks must be confirmed healthy before work begins.

One uplink temporarily unavailable
Potential reduction in path redundancy
Traffic behavior must be verified

Go / no-go decision

Assessment required

Complete the pre-change checklist and assess the proposed change before making a decision.

No decision recorded.

Change record

Awaiting risk assessment.

Network Insight · Interactive Lab 08

Packet Path Visualizer

Follow a simulated packet through a leaf–spine fabric. Step through each forwarding decision and see why traffic may cross a spine—or remain within a single leaf.

Traffic scenario

Selected spine for cross-leaf path

Fabric topology Ready to trace

Source endpoint Server A · 10.0.1.10

Current forwarding device Awaiting start

Destination endpoint Server B · 10.0.2.10

Step 0 of 4 0% complete

READY

Choose a traffic scenario

Start the path to inspect the source endpoint, ingress leaf, fabric hop, destination leaf and receiving endpoint.

Forwarding observation This is an illustrative model. It does not read live devices, routing tables or telemetry.

Path sequence

Use the sequence to see where the packet is in its journey.

Learning model only: the selected path represents one possible forwarding path. Actual paths depend on topology, forwarding state, routing, hashing, failures and the network design.

Network Insight · Interactive Lab 09

Forwarding Table Explorer

Select a fabric device and a destination address. Inspect the illustrative forwarding entries to understand how a switch chooses where to send a packet next.

Device to inspect

Destination IP address

Illustrative forwarding state Leaf 1 · L3 forwarding

Forwarding entries Select a row to inspect that destination prefix.

Destination prefix	Next hop	Interface

Lookup result Longest-prefix match

Queried destination

10.0.2.10

Next hop selected

The best matching entry determines the next forwarding action in this example.

Matched prefix 10.0.2.0/24

Next hop 192.0.2.2

Outgoing interface Ethernet1/2

Lookup method Longest-prefix match

How the lookup works

Read the destination address

The device examines the packet's destination IP address.

Find matching prefixes

More than one route may match. The most specific matching prefix is preferred.

Apply the forwarding action

The selected entry identifies the modeled next hop and outgoing interface—or a miss when no entry matches.

Important distinction: a routing table (RIB) contains route information used by routing processes. A forwarding table (often called a FIB) is used to forward packets. This lab uses simplified, preconfigured examples; it is not connected to a real switch.

Network Insight · Interactive Lab 10

Routing and Reachability Lab

Investigate why a destination may—or may not—be reachable. Compare route availability, next-hop resolution and forwarding-path status in a simplified leaf–spine fabric.

Investigation scenario

Ingress device

Simulated fabric path Awaiting test

Test outcome

Ready to investigate

Select a scenario and run the test to inspect the simulated route and forwarding state.

Route to destination Not tested

Next-hop resolution Not tested

End-to-end reachability Not tested

Diagnostic checklist

Inspect the routeConfirm the destination prefix exists on the ingress device. Validate the next hopCheck that the next hop is resolvable and has a usable adjacency. Check the forwarding pathVerify the relevant interfaces and fabric links are operational. Test the return directionCheck reverse-path routes and policy when bidirectional communication is required.

Engineer’s task: run a scenario, then check the diagnostics you would investigate before drawing a conclusion.

Investigation findings

Route presence

Has the ingress device learned or installed a usable route?

Next-hop usability

Can the selected next hop be resolved to a usable adjacency?

Path and return

Are the fabric path and return direction available?

Key principle: a route in the control plane does not by itself guarantee successful packet delivery. Next-hop resolution, forwarding programming, link state, policy and the return path can all matter.

This is a teaching simulation with predefined scenarios. It does not send real packets, query routers, or verify actual network state.

Network Insight · Interactive Lab 11

Troubleshooting Challenge

Work like a network engineer. Review the symptoms, choose the most useful diagnostic actions, submit your diagnosis, and then reveal the explanation.

Challenge

Incident briefing Challenge ready

Intermittent server connectivity

Applications on Server A report intermittent failures when communicating with Server B.

Your objective

Identify the most likely fault and choose the diagnostic checks that will confirm it.

Approach: begin with evidence. Avoid making configuration changes before you have isolated the fault.

Choose your diagnostic actions Select all actions you would perform before declaring a root cause.

Diagnosis feedback

Challenges completed 0 / 4

Best diagnostic score —

Current challenge score Not submitted

Educational simulation only. The displayed symptoms and faults are predefined examples, not live network telemetry. In production, confirm findings against device logs, counters, route tables, forwarding tables and application evidence.

Network Insight · Learning Assessment

Knowledge Check & Learning Progress

Test your understanding of leaf–spine fabrics, routing, forwarding, fault isolation and safe change practices. Review the explanation after each answer and finish with a summary of your results.

Questions answered 0 / 8 Completed questions

Correct answers 0 Knowledge demonstrated

Current result — Assessment not complete

Assessment progress 0%

Topic 1 · Fabric architecture

What is the primary role of a leaf switch in a leaf–spine fabric?

Choose one answer, then submit it to see the explanation.

Assessment complete

This assessment runs in your browser and is illustrative. Progress is held only while this widget remains active; it is not a logged-in learner record and is not sent to a server.