Throughput vs. Bandwidth vs. Speed

These terms are generally used interchangeably to refer to the "Mbps" number that you can find somewhere in wireless LAN products' specifications. They are all ways of referring to the amount of data ("Mb" or megabits) per unit time ("ps" or per second) that can be handled by the product.

Speed and Throughput actually can be used interchangeably. But think of them as describing the maximum rate that data can be handled for a single user.

Bandwidth, on the other hand, is more a description of maximum capacity and implies multiple users.

Said differently, a single user has all the capacity (bandwidth) of a network at his or her disposal. So that connection should run at the maximum speed (throughput). But as more users connect to the same network, that bandwidth is now shared among the users, so the per user speed will drop. If the user's speed drops below what the user's application requires, then problems can result.

Most network applications are designed to handle this basic fact of network life and respond by just slowing down. This is why web browsing is slower during evenings or when school lets out. Same bucket o' bandwidth; more users drawing from the bucket; less bandwidth per user.

But "real time" applications such as audio and video have less of an ability to deal with a slowdown in the delivery of bits. If bits don't arrive in time for audio, then voice gets garbled or drops out entirely. Video is even more sensitive and it doesn't take much to start to see pixelation and picture breakup as available bandwidth drops below what is needed.

Note that manufacturers have headed away from playing up the "Mbps" in wireless networking product advertising and marketing materials due, in part, to some quiet (and not so quiet) lawsuits alleging false speed and range claims for wireless LAN products. So you now find relative performance claims such as "10x speed" and "20x coverage", which are supposedly less misleading, but completely unhelpful in determining whether a wireless product is going to provide the speed or bandwidth that you require.