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Exam Information
Official specifications published by Arista
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Skills this practice test covers
- Configure VLANs, spanning tree, LACP and MLAG for a Layer 2 leaf-spine fabric.
- Build an eBGP underlay with ECMP and compare it with OSPF and IS-IS.
- Set up VXLAN with Head-End Replication and an MP-eBGP EVPN overlay.
- Choose symmetric or asymmetric IRB and configure EVPN active-active multihoming.
- Provision switches through CloudVision with configlets, Studios and zero touch provisioning.
- Upgrade and troubleshoot EOS with CLI tools, CloudVision and Advanced Event Management.
Explore related topics
ACE-L3-DCENG exam content
4 domains · 20 topics · 135 questions
Layer 2 Leaf-Spine Design and Technologies33 questions
This domain builds a Layer 2 leaf-spine (L2LS) fabric. Candidates configure VLANs, spanning tree, LACP port-channels and MLAG pairs, add VRRP or VARP gateways, and deploy the design from the CLI or with CloudVision configlets.
Skills tested
- Configure access and trunk ports, SVIs and inter-VLAN routing on Arista switches.
- Tune spanning tree with RSTP or MSTP and place the root bridge on purpose.
- Build an MLAG domain with its peer-link and heartbeat, and dual-home servers with LACP.
- Choose VARP over VRRP when both MLAG peers should forward gateway traffic.
- Deploy the same L2LS fabric once with the CLI and once with CloudVision configlets.
Questions by topic
- L2LS Architecture5
- VLANs6
- Spanning Tree Protocol (STP)6
- LACP5
- MLAG3
- Default Gateway Redundancy (FHRP)4
- Building L2LS Fabric4
Layer 3 Leaf-Spine Design and Underlay Routing32 questions
Here the fabric becomes routed. Candidates explain why a Layer 3 leaf-spine (L3LS) design scales past L2LS, compare OSPF, IS-IS and BGP as the underlay, and configure eBGP with ECMP load balancing.
Skills tested
- Explain the limits of L2LS that lead to an L3LS design.
- Compare OSPF, IS-IS and BGP as underlay routing protocols.
- Configure an eBGP underlay with multipath and ECMP load balancing.
- Run BGP alongside MLAG, including iBGP between the MLAG pair.
Questions by topic
- L3LS Design Overview6
- Underlay Routing - OSPF and IS-IS7
- BGP Fundamentals and eBGP Underlay10
- BGP Underlay Deployment Options9
VXLAN and EVPN Overlay40 questions
This domain adds an overlay to the routed underlay. VXLAN carries Layer 2 segments across the fabric, and EVPN uses MP-BGP to share MAC and IP reachability between switches. Candidates also build the overlay with CloudVision Studios.
Skills tested
- Map VLANs to VNIs and set up VTEPs with Head-End Replication.
- Configure MP-eBGP for EVPN with route distinguishers and route targets.
- Tell the EVPN route types apart, such as type 2 for MAC-IP and type 5 for IP prefixes.
- Choose symmetric or asymmetric IRB for a design and configure it on EOS.
- Configure active-active multihoming with an Ethernet Segment Identifier (ESI).
Questions by topic
- VXLAN Design and Control Plane7
- EVPN Advanced - IRB and Multihoming12
- VXLAN with MLAG and Best Practices6
- EVPN Fundamentals and Route Types12
- EVPN Design Best Practices and Studios Deployment3
CloudVision Platform30 questions
CloudVision manages the whole fabric. Candidates onboard devices, provision them with configlets, Studios and zero touch provisioning, watch them with dashboards, events and topology views, and upgrade and troubleshoot EOS.
Skills tested
- Onboard switches manually or with ZTP, and replace a failed switch with ZTR.
- Push configuration through change control, and roll it back when needed.
- Build dashboards and events that track device health and compliance.
- Upgrade EOS from the CLI and from CloudVision, including an MLAG ISSU upgrade.
- Automate responses with Advanced Event Management, such as the event monitor and event manager.
Questions by topic
- CloudVision Overview, Setup, and Provisioning11
- CloudVision Studios5
- Monitoring, Dashboards, Events, and Topology4
- EOS Operations and Troubleshooting10
Requirements
- No formal prerequisites: anyone can book the exam.
- Recommended: Arista's Data Center Engineering (DCENG) learning track, including its hands-on labs.
- Recommended: solid Layer 2 and Layer 3 protocol knowledge and a grasp of spine-leaf designs.
- Recommended: daily familiarity with Arista EOS and its CLI.
About the ACE-L3-DCENG exam
ACE-L3-DCENG shows that a network engineer can design, build and troubleshoot data center fabrics on Arista switches. It belongs to the Engineering sub-track of Arista's Data Center learning track, and Arista lists it as exam AN-DC-EN01. The exam is a hands-on lab, not a multiple-choice test: candidates configure virtual switches to build Layer 2 and Layer 3 leaf-spine networks, a VXLAN and EVPN overlay, and CloudVision management. Passing earns the ACE Specialist Data Center Engineering certification at Level 3.
The PlanetCert practice test checks the knowledge behind each lab task, and its largest share of questions is on VXLAN and EVPN. The explanations show why a choice works on the fabric, for example why Route Type 5 carries IP prefixes while Route Type 2 carries MAC and IP pairs. Study Mode suits the CloudVision domain, where onboarding, change control and Studios each follow their own steps. Brainy AI Assistant can compare symmetric and asymmetric IRB or explain what the MLAG peer-link carries.
How to earn the certification
- Earns
- ACE Specialist Data Center EngineeringSpecialist (Level 3)
The certification is valid for two years. A new certification at the same or a higher level, in any track, renews it.
- After
- ACE-L7 ACE Expert
Arista's highest level, covering networking and security architecture across all tracks. It has a pre-qualification requirement.
- ACE-L7 ACE Expert
How to prepare for ACE-L3-DCENG
- 1
Book time in a virtual lab
The exam is entirely hands-on, so practise on virtual EOS switches, for example with Arista's ATD lab guides. Rebuild each lab from a blank configuration more than once.
- 2
Build the Layer 2 fabric twice
Configure VLANs, spanning tree, LACP, an MLAG pair and VARP by hand. Then deploy the same design with CloudVision configlets and compare the running configurations.
- 3
Route the underlay with eBGP
Peer every leaf with the spines over eBGP and confirm ECMP paths to each loopback. Then rebuild the underlay with OSPF or IS-IS to see the trade-offs.
- 4
Layer EVPN onto the underlay
Add VXLAN first, then MP-eBGP EVPN for Layer 2 services, then symmetric IRB for routing. After each step, read the EVPN routes the switches exchange.
- 5
Close gaps with practice questions
Use the ACE-L3-DCENG practice test in Study Mode after each lab block. Ask Brainy AI Assistant to explain any missed question, then repeat that task on the switches.
Start a timed ACE-L3-DCENGrun
Arista's official preparation is the Data Center Engineering Track (DCENG), offered as self-paced Arista Academy Digital or as instructor-led Arista Academy Live.
Who ACE-L3-DCENG is for
- Data center network engineers who build and run Arista leaf-spine fabrics.
- Network architects who plan VXLAN and EVPN designs on Arista EOS.
- Engineers moving a Layer 2 data center to a routed leaf-spine design.
- CloudVision administrators who provision and monitor Arista switches.
Typical job titles: Data center network engineer · Network engineer · Network architect · Infrastructure engineer · Network automation engineer
ACE-L3-DCENG glossary
19 terms from the exam objectives and the vendor's official material, each defined in a sentence.
- Advanced Event Management (AEM)
- EOS tools such as the event monitor, event manager and CLI scheduler that record events and run actions automatically.
- Asymmetric IRB
- An EVPN routing model in which the ingress switch both routes and bridges, so every switch needs every VLAN and VNI.
- Configlets
- Blocks of EOS configuration stored in CloudVision and applied to devices or to containers of devices.
- CVaaS
- CloudVision as-a-Service: the version of CloudVision that Arista hosts in the cloud, instead of an on-premises cluster.
- CVP Studios
- CloudVision's input-driven way to build and change network configuration, in place of hand-written configlets.
- Ethernet Segment Identifier (ESI)
- The value that marks the links from one host to several switches as one segment for EVPN multihoming.
- EVPN
- Ethernet VPN: a BGP control plane that tells each switch which MAC and IP addresses sit behind which VTEP.
- Head-End Replication (HER)
- A VXLAN method in which the sending VTEP copies broadcast traffic to each remote VTEP itself, so the underlay needs no multicast.
- L2LS
- Layer 2 leaf-spine: a data center design in which the links between leaf and spine switches carry bridged Layer 2 traffic.
- L3LS
- Layer 3 leaf-spine: a design in which every leaf-to-spine link is routed, with VXLAN carrying Layer 2 traffic where it is needed.
- LACP (Link Aggregation Control Protocol)
- The protocol that bundles several physical links into one port-channel and checks that both ends agree.
- MLAG (Multi-Chassis Link Aggregation)
- Two switches acting as one at Layer 2, so a server can connect to both with a single port-channel.
- Symmetric IRB
- An EVPN routing model in which both the ingress and the egress switch route, using a shared Layer 3 VNI for each VRF.
- VARP (Virtual ARP)
- An Arista gateway method in which both MLAG peers share one virtual IP and MAC address, and both route traffic.
- VNI (VXLAN Network Identifier)
- The number that names one VXLAN segment, much like a VLAN ID but with far more possible values.
- VRRP (Virtual Router Redundancy Protocol)
- A standard gateway redundancy protocol in which one router is active and another takes over if it fails.
- VTEP (VXLAN Tunnel Endpoint)
- The switch function that wraps Layer 2 frames in VXLAN packets and unwraps them at the far end.
- Zero Touch Provisioning (ZTP)
- A process in which a new switch fetches its software and configuration automatically when it first boots.
- Zero Touch Replacement (ZTR)
- A CloudVision process that gives a replacement switch the configuration and identity of the switch it replaces.