What Is Bandwidth?
Bandwidth — the maximum amount of data a network link can carry per second, measured in bits per second (Mbps, Gbps). It's the width of the pipe, not the speed of the water.
How it works
Every link has a rated capacity — a 100 Mbps port can move at most 100 megabits each second. Actual file-transfer speed is usually lower because of overhead, congestion and the slowest link in the path (the bottleneck). Bandwidth is shared: ten users on one 100 Mbps uplink contend for the same capacity.
Why it matters
Bandwidth drives network design (uplink sizing, EtherChannel bundling) and appears throughout CCNA — OSPF even computes its route costs from interface bandwidth. Distinguish it from latency: a link can be huge yet slow to respond.
Frequently asked questions
What is bandwidth in simple words?
The maximum data a connection can carry per second — like the number of lanes on a highway, not the speed of the cars.
Is higher bandwidth always faster?
Not necessarily — latency, congestion and the slowest hop in the path also decide real-world speed.
How is bandwidth measured?
In bits per second: Mbps (megabits) and Gbps (gigabits) are the common units for links.
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