Small business networks are simple, usually have a single WAN connection (DSL/cable/Ethernet), and are run by a local or contracted IT person rather than a dedicated department.

Most businesses are small, so most business networks are small too. Because the scale is modest, the design stays simple: a single Wide Area Network (WAN) link reaches the internet through one Internet Service Provider (ISP), and a switch fans that connectivity out to end devices, with a wireless access point added for mobile clients. The defining contrast with a large enterprise is staffing — a large network needs a dedicated IT department to maintain, secure, and troubleshoot it, whereas a small network is typically handled by one local technician or an outside contractor. This matters because it shapes every later decision: device choices, redundancy, and monitoring all have to be manageable by one person on a limited budget.

* A single WAN link to the ISP, a router, and one switch fanning out to wired hosts plus a wireless AP. *

Small Network Characteristics:

• The majority of businesses are small, so most business networks are also small
• A small network design is usually simple
• Small networks typically have a single WAN connection provided by DSL, cable, or an Ethernet connection

Management:

• Large networks require an IT department to maintain, secure, and troubleshoot devices and protect organizational data
• Small networks are managed by a local IT technician or a contracted professional

Typical Small Network Topology:

• Router connected to internet via ISP
• Switch connecting end devices
• Wireless access point for mobile devices
• Servers and workstations

Go deeper:

• Wikipedia — Network topology — physical vs logical layouts (the small network is a switched star) and the standard topology types.