Hello, Seyed. This is controlled by your Routing Application (ORS or URS) in conjunction with Stat Server, using what is called "Capacity Rule". Basically, when you are routing an interaction, the routing application enquires Stat Server to see which targets fit your specific criteria. Stat Server, in turn, will check which agents with such criteria are available that have "capacity" to be routed to.
With capacity rules, you can specify which media can be answered at the same time (lets say you want an agent to be able to handle Voice+Chat) and how many of each.
You can read more about it here (old version of the capacity plugin, but the same concepts apply):
https://docs.genesys.com/Special:Repository/81g_pg_rescap.pdf?page=Documentation/System&id=c38105a7-175a-4ae9-ac3e-3b40532b3751
The current way to set up capacity rules is through GAX. You can learn more about it here:
https://docs.genesys.com/Documentation/GA/latest/user/CapacityRules
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Henrique Sujdik
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