Do Multiple Users Using the Internet Affect Speed?

High-speed Internet connections vary wildly in the amount of bandwidth available. Some DSL connections allow as little as 256,000 bits of data per second, or 256 kbps, while high-end cable connections can promise over 100 Mbps, or 100,000,000 bits of data per second. Lower-end connections will be noticeably affected when more than three people connect, while high-bandwidth connections can accommodate a whole office building without significant slowdown.

Before the Internet bandwidth becomes a factor, users must contend with local bandwidth. Wireless routers advertise 54mbps for 802.11g networks, and up to 300mbps for 802.11n networks. However, a single wireless network shares this maximum bandwidth among all devices connected to that wireless network. A single user on the wireless network can, in theory, transmit at 300mbps on an 802.11n network. However, five users on that same network, communicating at the same time, could only theoretically achieve 60mbps.

Wired connections, by contrast, generally connect to a switch. Switches regularly offer speeds up to 1 Gbps, or 1,000 Mbps, which is not shared by any other device. Lower-end switches, such as those embedded in popular wireless Internet routers, can be overloaded if more than approximately 10 users simultaneously stream data. However, wired connections typically do not experience the same slowdowns as wireless users. When possible, connect stationary devices, such as desktop PCs, to the Internet via wired connections.

Simply browsing the Internet does not require a constant high-speed connection. Browsing simple Web pages and working with email consumes only a small portion of bandwidth, even if dozens of users are doing so at the same time. Even Voice over Internet Protocol phones require only a few dozen kilobits of speed to function. Streaming video and large downloads, however, can demand as much bandwidth as the connection will allow. If every user streams high-definition video simultaneously, or if many users are downloading large files on a regular basis, it won’t take long to notice a considerable impact on the network.

One often-overlooked factor affecting Internet speed is upload bandwidth. Whenever you visit a Web page, your computer must first send a request for that page. These requests consume far less bandwidth than the resulting download, but they must go through before a download can begin. To save costs, many ISPs will offer high download speed, but much lower upload speeds. If a user on the network uses a significant amount of upload bandwidth by sending large files, it can be difficult for other users to submit their own requests for downloads, resulting in the perception that the Internet connection has slowed down.