You can create many clusters like that and then connects them with theirselfs. At the beginning you can simple copy skynet.php to another file, e.g. skynet2.php - if you do this you will have two Skynet clusters.
At next, you can create more, e.g. skynet3.php, skynet4.php, etc. Finally you can put them on different servers if you want. All of there standalone clusters will build your network.
At first launch of every cluster, Skynet will build database (SQLite is default and is recomennded). Every cluster creates their own database file named .CLUSTER_NAME.db (if SQLite is used). Of course you can use antother database engine (e.g. MySQL) and then Skynet will work on database like that, but SQLite is preferred. This is the idea: one cluster + one database file. From now, Skynet will store data about another clusters in their own database. This clusters list will be at next sended to another registered clusters so clusters knowed by one cluster will be shared with another cluster and added to their database. Every cluster will know about other clusters, that's the idea of this network.
When at least one another cluster is knowed by your cluster you are allowed to share data and commands between them. Sending data between clusters is based on request-response architecture: one cluster sends request to another, and the another creates response from request then returns it to requesting one. With more that one cluster those requests and responses can be sending over whole network. Skynet resends information about knowed (registered) clusters to anothers when connects to them, so if you have 3 clusters, e.g. skynet1.php, skynet2.php, skynet3.php you need to connect them each other at first. How to do this? When you connect first cluster with second cluster at first time the second cluster will get and store address of first cluster in their database and the first cluster will store address of second cluster. At now, if you connect second cluster with cluster number three, the cluster numer three will get (and store) address of second cluster... and the first cluster. It's not the end, becose after that, cluster number three will connect with first cluster and sends them their address. At now, every clusters will "see" each other. If you then add another - four cluster and connect to it from cluster one - all of clusters will receive information about new cluster (becose cluster one will inform them).
When Skynet knows about another clusters then starts broadcasting to all of them and allows to sending them requests (addressed to specified clusters, or adressed to whole network) and receiving responses from them. Every cluster is a sender and responder at once, so communication is in two-sides. Every request can have prepared parameters and commands specified by cluster or by user (and other cluster can responds for them with defined action).
