EVPN MultiHoming - Cloud Managed Fabric
EVPN MultiHoming with Catalyst 9000 switches
EVPN Multi-Homing (EVPN-MH) is an extension to Cloud-Managed Fabric with support for active-active dual-homing at the Distribution Layer. It allows an access switch or downstream device to connect redundantly to a pair of fabric leaf switches while keeping both uplinks forwarding.
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This design improves resiliency and link utilization without requiring an immediate move to a routed access design. It is especially useful for environments that want to preserve an existing Layer 2 access model while introducing EVPN-VXLAN in the distribution block.
In a Cloud-Managed Fabric deployment, EVPN-MH is supported at the distribution layer on supported Catalyst 9000 platforms. The EVPN-MH pair behaves as a logical dual-homed leaf pair for downstream connectivity, while the broader fabric continues to provide the EVPN control plane and VXLAN overlay services.
With EVPN-MH, downstream traffic can use both uplinks toward the distribution pair. This provides the following benefits:
· Active-Active forwarding across the distribution pair
· Better resiliency during link or node failures
· Continued use of a familiar Layer 2 access design
· Easier migration into fabric without redesigning the entire campus
EVPN Multi-Homing with Meraki Dashboard
From a design perspective, EVPN-MH is a good fit when the access layer remains Layer 2 and dual-attached uplinks are required for redundancy and operational continuity.
eraki Dashboard provides a workflow to create and manage an EVPN-MH pair before that pair is added into the fabric. This separates the peer formation workflow from the fabric onboarding workflow and makes the deployment sequence easier to understand.
At a high level, the workflow is:
1. Create the EVPN-MH pair in the Switching section.
2. Add the EVPN-MH pair to the fabric as a leaf.
3. Provision the required subnets on the EVPN-MH leaf pair.
Connect downstream access switches by using bundled uplinks.
This sequence matters. The EVPN-MH peer must be created first. After it exists as a paired entity, it can be consumed by the Cloud Fabric workflow like any other supported leaf object.
Hardware Requirements
· Catalyst 9300X
· Catalyst 9500H
Software Requirements
· IOS XE 17.18.3
· IOS XE 26.1.1
Network Requirements
· EVPN-MH is supported at the distribution layer
· All current Cloud Fabric overlay types are supported with EVPN-MH
· EVPN-MH pair must be created before it is added to the fabric
EVPN Multi Homing Workflows
EVPN Multhihoming pair can be created via a new Dashlet as shown here. This pair is created outside
the fabric workflow and can be added as a Leaf device into the Fabric. Follow below steps to create
to create an EVPN MH pair on the dashboard.
1) Create a EVPN-MH pair using EVPN Multi-Homing workflow.
2) Add to the Fabric as a leaf Device
3) Provision the subnets on the EVPN-MH pair.
Click Create EVPN-pair to select the device.
Create an EVPN-MH pair name, select devices that are part of the EVPN-MH pair
Configure EVPN-MH pair configs.
- BGP ASN: Choose the Fabric BGP ASN
- Loopback Interface: This loopback is used to create Inter BGP ( L2VPN-AF ) peering between Leaf devices. You can drop down to select an existing loopback or create a new loopback in this workflow. ( loopback 100 is not allowed )
- IP Address: This is the loopback IP address associated to the loopbacks created above
- EVPN-MH port-channel: This is the Inter-ES port-channel between the Leaf devices. Click existing connections and select the interfaces that will be bundled for Inter-ES port. If you have an existing port-channel pre-configured that can be used from drop down as well.
- IP Address: These are the IP addresses associated to the Port-channel. OSPF will be automatically enabled on the port-channel interface to create a routed port-channel between Inter-ES peers.
Once you save, this will create a unique EVPN-MH peer in the Dashboard
Add EVPN-MH pair to Fabric
Go to the Organization, Fabric, Click on the Fabric where the EVPN-MH pair will be provisioned.
Click on Device Roles & Add Devices and select the Network where the EVPN-MH pair was created. You should now see the EVPN-MH pair that can be added to the Fabric.
Select the EVPN-MH pair to be added to the Fabric
Click on Actions and select the Leaf role for the Device
Provision Subnets on the EVPN-MH pair
Click on Fabric Subnets, Click on Actions for a specific subnet, select the EVPN-MH pair & Save Subnet
This will create necessary EVPN-MH config on the Leaf devices and add it to the Fabric. Last step is create port-channels to the Access switches. This is outside the fabric Workflow.
Port-channel's to Access switches
Port-channels must be created on the EVPN-MH pair devices as well as Access switches that are Dual Homed to the EVPN-MH pair.
Switching, Switch Ports page can be used to created port-channels on Access and EVPN-MH pair devices.
Filter by Switch name, check the ports and click Aggregate to bundle the ports
Do the same for the EVPN-MH pair, select the port on each Leaf device and click Aggregate, this will create port-channel on both Leaf devices.
Leaf devices that are part of the EVPN-MH pair will now learn the clients off the Access switches via the port-channel.
Post-Deployment Verification
Additional Resources