A BYOC Premises Edge group is an association of premises-based Edges that enable a collection of network devices to communicate on a low latency LAN or a WAN, when required. 

A BYOC Premises Edge group provides the following benefits to your organization:

• All the phones associated with each premises-based Edge communicate with all of the other phones in the Edge group. 
• Members of an Edge group share endpoints. For example, all of the phones in the same Edge group can access a SIP trunk plugged into one Edge in the group.

Shared Resources in an BYOC Premises Edge Group

• Phone trunks:  When you add an Edge to an Edge Group, that Edge inherits phone trunks added to the Edge group.
• Communication providers:  When one Edge in the Edge group has a connection to a communication
  provider, all of the other Edges in the Edge group can share the resource.
• External Gateways:  When one Edge in the Edge group has a connection to an External
  gateway, all of the Edges in the group can share access to the gateway.
• Other communication providers:  Other communication providers can include WebRTC,
  SIP carriers, and Voice over IP gateways. As long as one of these resources
  have a connection to one Edge in the Edge group, all of the other Edges in the group
  share them.

Edge group setup is is detailed in Create a BYOC Premises Edge group with a phone trunk.

Local site routing for BYOC Premises Edge groups

Local site routing improves call routing and Edge utilization for multi-site implementations. When possible, the system routes calls through local, same site Edges to save bandwidth and reduce latency.

Genesys Cloud is designed to use premises-based Edges within the same site if possible. Genesys Cloud will only use premises-based Edges in other sites if the Edges on the local site are offline, are already at capacity,  or if the required resource, such as an agent, a station, or trunk is only available on an Edge located on a different site.