A computer network can be too small, connecting two computers back-to-back, a SOHO network, or it can be too large, connecting all devices in a huge enterprise network. In an enterprise network, data originates and travels in different environments like Main Office (Head Office), Remote Locations (Branch Offices, Users working from their home, travelling employees etc.).
Main Office (Head Office): A Main Office (Head Office) is where all the branch offices are reporting to and where the top departmental heads of the enterprise works. Main Office (Head Office) network is where the branch office networks are normally connected to. Normally, it is inside the main office that the most important Enterprise Servers run.
Remote locations include Branch offices, Work from home users and Travelling employees.
Branch offices: Branch offices are normally located in remote geographical locations, connected to the main office by Wide Area Network (WAN). Branch offices normally contain fewer users (employees) than the Main Office (Head Office) and the network resources in Branch Office are limited to the users in Branch Office. Branch offices normally host less important servers.
Work from home users: Home Users are the employee users who work from home. Home users are normally connected to the Main Office (Head Office) / Branch Office using VPN (Virtual Private Network) protected broadband internet.
Travelling Employees: Travelling Employees are usually managers, sales & marketing employees or technical employees who are at a remote location for a business related activity. Travelling Employees are also normally connected to the Main Office (Head Office) / Branch Office using VPN (Virtual Private Network) protected broadband internet.
When we network multiple physical sites (Example, Main Office and all the Branch Offices) using Wide Area Network (WAN) links, three different topologies are commonly used.