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Arista EOS lab 14 of 20

Troubleshooting an EVPN-VXLAN fabric

The two-leaf EVPN fabric from lab 9 was rebuilt from a template, and now nothing crosses it properly. Validate the underlay, the overlay sessions, the layer 2 service and the layer 3 service in order, and fix five planted faults: a missing VTEP prefix, missing extended communities, a spine rewriting next hops, a route-target typo and an L3 VNI mismatch.

Run this lab

It needs Standard: its 7 nodes are set to 7 vCPU and 9,728 MB in total.

In your workspace: Shared, then Arista EOS guided labs, then 14 - Troubleshooting an EVPN-VXLAN fabric

Run it on Standard from £5 a day

The free demo can’t run it: it has 6 vCPU and 8 GB, and this lab’s nodes need 7 vCPU and 9,728 MB together. Every lab plan includes every guided lab.

Level
Advanced
Time
About 90 minutes
Nodes need
7 vCPU, 9,728 MB
Smallest plan
Standard

The scenario

Over the weekend Northwind rebuilt pod 1 from a configuration template: two spines, leaf1 (rack 1) and leaf2 (rack 2), tenant VRF TENANT-A with symmetric IRB, exactly the design of lab 9. Monday's tickets:

  • "Web server h1 can't reach its cluster partner h3" (same subnet, VLAN 10, other rack);
  • "Web tier can't reach the database h2 or the shared service 10.99.99.1".

There are five faults. Validate the fabric in stages (underlay → overlay sessions → layer 2 service → layer 3 service), fix each fault with the smallest change, and record the evidence.

HostLeaf / portVLANAddressGateway
h1leaf1 Et310 WEB10.10.10.11/2410.10.10.1
h3leaf2 Et410 WEB10.10.10.13/2410.10.10.1
h2leaf2 Et320 DB10.20.20.12/2410.20.20.1
serviceleaf2 Loopback100 (TENANT-A)–10.99.99.1/32–

What you’ll practise

  • Validate an EVPN fabric in stages: underlay, overlay sessions, L2 VNI, L3 VNI
  • Prove VTEP reachability with routes and source-based pings
  • Read EVPN route details: next hop, extended communities (route targets), VNIs
  • Recognise the signature of a spine that rewrites the next hop
  • Fix RT and VNI mismatches and explain why routed and bridged traffic failed differently

The tasks

  1. Reproduce the tickets
  2. Stage 1: the underlay
  3. Stage 2: overlay sessions and route attributes
  4. Stage 3: the layer 2 service (VNI 10010)
  5. Stage 4: the layer 3 service (VNI 50001)

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of Troubleshooting an EVPN-VXLAN fabric7 nodes, 7 links. Every link is listed as text below the diagram.spine1spine2leaf1leaf2h1h2h3Ethernet3eth0Ethernet3eth0Ethernet1Ethernet1Ethernet2Ethernet2Ethernet4eth0Ethernet2Ethernet1Ethernet1Ethernet2
7 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • spine1 Ethernet1 to leaf1 Ethernet1
  • spine1 Ethernet2 to leaf2 Ethernet1
  • spine2 Ethernet1 to leaf1 Ethernet2
  • spine2 Ethernet2 to leaf2 Ethernet2
  • leaf1 Ethernet3 to h1 eth0
  • leaf2 Ethernet3 to h2 eth0
  • leaf2 Ethernet4 to h3 eth0
Nodes in Troubleshooting an EVPN-VXLAN fabric, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
spine1Arista vEOSveos-4.33.1.1F1 vCPU, 2,048 MB
spine2Arista vEOSveos-4.33.1.1F1 vCPU, 2,048 MB
leaf1Arista vEOSveos-4.33.1.1F1 vCPU, 2,048 MB
leaf2Arista vEOSveos-4.33.1.1F1 vCPU, 2,048 MB
h1Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB
h2Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB
h3Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder Arista EOS guided labs.

  3. Open 14 - Troubleshooting an EVPN-VXLAN fabric and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

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CloudLabBox is independent of Arista Networks. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.