By Default the VCS ships with a Default Subzone, Traversal Subzone, and a Default Zone. There are links pre-configured between them. If the VCS is in a cluster, an additional link, DefaultSZtoClusterSZ, between the Default Subzone and the Cluster Subzone is also established.The pre-configured links will look something like this:
DefaultSZtoTraversalSZ, DefaultSZtoDefaultZ and TraversalSZtoDefaultZ
You can edit any of these default links in the same way you would edit or manually configured links by navigating to the Links page (VCS configuration > Bandwidth > Links) which lists all existing links and allows you to create, edit and delete links. If a subzone has no links configured, then endpoints within the subzone will only be able to call other endpoints within the same subzone.
If for some reason the links fail to automatically generate you can ssh into the VCS, login as admin, and issue the below command to reinstate them.