When there is an available slave core in an installation it will synchronize with the master core configuration. The master core will offload much of its work to that slave (hence the name) so that the master core can concentrate on more important things. The slave core takes care of handling authorization of clients as well as alarm scenarios. The master core manages the configuration database and handles things like backup, events, and report mode. Once the master core receives events from the slave core, the events will be deleted from the slave core. It is important, therefore, to be aware of where a slave core is installed since its location can actually be a detriment to the system.
In the sample layout shown below, when the operator logs in with Ocularis Client, if there is an available slave core, it will take over for the master core for user authentication. Since the slave in this example (on server D) is not on a local network, performance is dependent on the bandwidth across the WAN. This will likely cause sluggish performance for the operator at best.
In this case, you should add a slave core to Server C alongside the DM.
Having a slave here makes more sense. However, we now just broke the first general rule about not having more than one slave at the company level. Therefore, we need to add a branch to accommodate the remote slave core.