Clarify that perf scale guidance applies to SDN not OVN

Author: ahardin-rh

scalability_and_performance/planning-your-environment-according-to-object-maximums.adoc

@@ -9,6 +9,11 @@ Consider the following tested object maximums when you plan your {product-title}
 
 These guidelines are based on the largest possible cluster. For smaller clusters, the maximums are lower. There are many factors that influence the stated thresholds, including the etcd version or storage data format.
 
+[IMPORTANT]
+====
+These guidelines apply to {product-title} with software-defined networking (SDN), not Open Virtual Network (OVN).
+====
+
 In most cases, exceeding these numbers results in lower overall performance. It does not necessarily mean that the cluster will fail.
 
 include::modules/openshift-cluster-maximums-major-releases.adoc[leveloffset=+1]

scalability_and_performance/recommended-cluster-scaling-practices.adoc

@@ -9,6 +9,8 @@ toc::[]
 [IMPORTANT]
 ====
 The guidance in this section is only relevant for installations with cloud provider integration.
+
+These guidelines apply to {product-title} with software-defined networking (SDN), not Open Virtual Network (OVN).
 ====
 
 Apply the following best practices to scale the number of worker machines in your {product-title} cluster. You scale the worker machines by increasing or decreasing the number of replicas that are defined in the worker machine set.

scalability_and_performance/recommended-host-practices.adoc

@@ -7,6 +7,11 @@ toc::[]
 
 This topic provides recommended host practices for {product-title}.
 
+[IMPORTANT]
+====
+These guidelines apply to {product-title} with software-defined networking (SDN), not Open Virtual Network (OVN).
+====
+
 include::modules/recommended-node-host-practices.adoc[leveloffset=+1]
 
 include::modules/create-a-kubeletconfig-crd-to-edit-kubelet-parameters.adoc[leveloffset=+1]