Inter-branching is the process of securely connecting 2 or more geographically separated offices together using some sort of VPN technologies, so they can share resources from the home office where the main servers and services resides.
Connection will be over WAN or INTERNET link, using cariers such as Laser Beam, Microwave, Broadband, Fiber Optics and DSL. Depends on the location of the offices and the distance between them.
Virtual Private Network ( VPN ) is the technology used for such services, it is usually configured on a dedicated device or a pre-existing Firewall on your premises, if there are no firewalls or VPN gateways one will be provided in each location.
Inter-branchig works by installing custom routers that support hardware encryption, VPN and WAN optimization in every site, branch or home office you have.
Then routing configuration will be installed on each remote branch so that any or specific traffic ( Source and Destination Policy Based Routing are supported ) goes to the home office via the VPN tunnel.
This will virtually feel that you are sitting right in your office, capable of using Your ip Phone, shared storage, accounting application, etc ... without installing a dedicated server or publishing your application to the internet.
Billing for such services depends whether you have a VPN capable device or not, how many offices you have and how much bandwidth you need over the link.
These requirements will be determined after a survey, where your applications, network and geographical location will be checked.