Kilobit to Exabit

The iconic dial-up handshake screech was a negotiation protocol between two modems. The initial tones tested line quality; the harsh noise burst was both modems rapidly cycling through modulation schemes (V.34, V.90) to find the fastest reliable speed — typically 28.8–56 kb/s. The sounds encoded training sequences, equaliser coefficients, and error-correction parameters, all transmitted as audio tones over a voice telephone line designed for 3.4 kHz bandwidth. The entire handshake lasted 10–30 seconds and transferred only a few kilobits of control data before the connection went silent for actual data transfer.

128 kb/s is considered acceptable quality for casual listening; 192–256 kb/s is a good balance of quality and file size; 320 kb/s is the maximum MP3 bitrate and is near-indistinguishable from lossless for most listeners. At 128 kb/s, one hour of audio is roughly 57 MB; at 320 kb/s, the same hour is about 144 MB.

No. A kilobit (kb) = 1,000 bits (SI, decimal). A kibibit (Kibit) = 1,024 bits (IEC, binary). The difference is small at this scale (2.4%) but compounds into significant gaps at larger prefixes. Network and telecom equipment use decimal kilobits; some older computing hardware documentation may use the binary definition.

The fastest consumer dial-up modems reached 56 kb/s (V.90 / V.92 standard), though practical speeds were often 40–50 kb/s due to line quality. At 56 kb/s, downloading a 5 MB MP3 file took about 12 minutes. By comparison, a modern 100 Mbps broadband connection is roughly 1,800 times faster.

Common audio bitrates: voice calls use 8–64 kb/s (G.711 codec = 64 kb/s); AAC audio at 96–256 kb/s; MP3 at 128–320 kb/s; lossless FLAC at 700–1,400 kb/s depending on audio content. Streaming services like Spotify use 24 kb/s (low) to 320 kb/s (premium) for music delivery.

One exabit = 10¹⁸ bits = 125,000 terabytes = 125 petabytes. If every person on Earth (8 billion people) each stored 15 GB of data — roughly a modern smartphone's photos and messages — the total would be about 120 exabytes, or about 960 exabits. The entire human genome is about 1.5 GB; sequencing every person on Earth would produce about 12 exabytes of data.

Cisco's annual internet traffic reports estimated global IP traffic at roughly 4.8 exabytes per day in 2022, rising about 20% per year. Expressed in bits, that's about 38 exabits per day or roughly 440 petabits per second continuously. Video streaming accounts for over 60% of total internet traffic volume.

Data gravity is the principle that massive datasets attract applications, services, and additional data toward them — rather than being moved to where processing occurs. At exabit scale, physically transferring data becomes impractical: moving 1 exabit over a 100 Gbps link takes 116 days. Instead, companies deploy compute resources alongside the data. This effect drives cloud concentration — once an organisation stores exabits in AWS or Azure, the cost and latency of moving that data elsewhere creates powerful vendor lock-in, shaping the economics of the entire cloud industry.

The Square Kilometer Array (SKA), under construction in Australia and South Africa, will be the world's largest radio telescope. Its thousands of antennas will collectively produce roughly 1 exabit of raw sensor data per day — more than the entire global internet traffic of the early 2000s. This data cannot be stored in full; instead, on-site supercomputers reduce it by a factor of ~10,000 in real time, keeping only scientifically relevant signals. The SKA illustrates how radio astronomy pushes data processing to extreme scales that rival commercial internet infrastructure.

At 1 Gbps (a fast home connection), downloading 1 exabit would take 1 billion seconds — about 31.7 years. At 1 Tbps (a high-end data center link), it would take 1 million seconds, or about 11.6 days. This illustrates why exabit-scale data movements require massively parallel infrastructure — no single link or device handles exabit transfers directly.