"more bandwidth means a faster connection"

networkingISP & telecom

Bandwidth is lane count; latency is trip time. Past a modest threshold, page loads, calls, and games are ruled by latency and bufferbloat - which a bigger plan does not fix.

Jim Gettys' bufferbloat work showed oversized queues wrecking responsiveness on 'fast' lines; modern queue management (fq_codel, CAKE) fixes what upgrades cannot.

Bandwidth is how much data can be in flight; latency is how long a single item takes to arrive. Confusing them is why buying a faster connection so often fails to fix the thing people wanted fixed, and the distinction has a physical floor that no purchase can move.

The classic illustration is that a truck full of hard drives has enormous bandwidth and terrible latency. More practically, a video call needs low latency and modest bandwidth, while a large download needs the opposite, and a connection that is excellent for one can be poor for the other. Light in fibre takes a fixed time to cross a continent, so no upgrade improves the round trip to a distant server.

The interaction that catches people out is bufferbloat: oversized buffers in network equipment absorb bursts and, in doing so, add enormous delay under load, which is why a connection with high advertised speed can become unusable for interactive work while a download runs. The fixes are queue management rather than capacity, which is why adding bandwidth so often does not help, and why the useful measurement is latency under load rather than peak throughput on an idle line.

Disputed / commonly mistold A popular version of this story is inaccurate - see the note above.

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