/arch.svg title="Multiple primary clusters on separate networks"><img class=element-to-stretch src=/v1.18/docs/setup/install/multicluster/multi-primary_multi-network/arch.svg alt="Multiple primary clusters on separate networks"></a></div><figcaption>Multiple primary clusters on separate networks</figcaption></figure><h2 id=set-the-default-network-for-cluster1>Set the default network for <code>cluster1</code></h2><p>If the istio-system namespace is already created, we need to set the cluster&rsquo;s network 