Draft of text

Author: johnmarco

articles/openshift/howto-sdn-to-ovn.md

@@ -1,6 +1,6 @@
 ---
 title: Migrate from OpenShift SDN to OVN-Kubernetes
-description: Discover how migrate from OpenShift SDN to OVN-Kubernetes.
+description: Discover how to migrate from OpenShift SDN to OVN-Kubernetes.
 author: johnmarco
 ms.author: johnmarc
 ms.service: azure-redhat-openshift
@@ -10,6 +10,31 @@ ms.date: 02/11/2025
 ---
 # Migrate from OpenShift SDN to OVN-Kubernetes
 
+OpenShift SDN, a component of Red Hat OpenShift Networking, is a network plugin that uses software-defined networking (SDN) to create a unified network for your cluster. This network allows communication between pods across the OpenShift Container Platform. OpenShift SDN manages this network by configuring an overlay network using Open vSwitch (OVS).
+
+OpenShift SDN has been deprecated since version 4.14 and will no longer be supported starting with version 4.17.  Therefore, if your cluster is using OpenShift SDN, you must migrate to OVN-Kubernetes before upgrading to any major OpenShift version beyond 4.16. OVN-Kubernetes is now the only supported network plugin.
+
+## Migrating to OVN-Kubernetes for Azure Red Hat OpenShift
+
+If your Azure Red Hat OpenShift (ARO) cluster is using the OpenShift SDN network plugin, you must migrate to the OVN-Kubernetes plugin before updating to version 4.17.
+
+> [!IMPORTANT]
+> Azure Red Hat OpenShift only supports the Limited live migration process.  Don't use the offline migration process.
+> 
+If you installed your ARO cluster with version 4.11 or later, OVN-Kubernetes was the default network plugin. You likely don't need to perform a migration.
+
+OpenShift SDN remains supported on Azure Red Hat OpenShift through version 4.16. See the [Azure Red Hat OpenShift release calendar](support-lifecycle.md#azure-red-hat-openshift-release-calendar) for end-of-life dates.
+
+To determine which network plugin your cluster currently uses, run the following command:
+
+```
+oc get network.operator.openshift.io cluster -o
+jsonpath='{.spec.defaultNetwork.type}'
+```
+
+See [Limited live migration to the OVN-Kubernetes network plugin overview](https://docs.openshift.com/container-platform/4.16/networking/ovn_kubernetes_network_provider/migrate-from-openshift-sdn.html#nw-ovn-kubernetes-live-migration-about_migrate-from-openshift-sdn) for steps to perform the migration.
+
+