How to Move 1,000 TB from Nanjing to Beijing in a Day: Network Limits and the Human‑Courier Hack

Network Transfer Estimate

To move a 1 000 TB (≈1 000 000 GB) dataset from Nanjing to Beijing, the author consulted a telecom operator for typical bandwidths:

Residential broadband: downlink up to 1 Gbps, uplink 300 Mbps.

Enterprise dedicated lines:

Data‑center line: up to 100 Gbps, cost ≈ 350 000 CNY per month.

Internet line: up to 10 Gbps, cost ≈ 540 000 CNY per month.

Assuming a 100 Gbps data‑center line, the theoretical maximum throughput is: 100 Gbps ÷ 8 = 12.5 GB/s Data transferred per hour: 12.5 GB/s × 3600 s = 45 000 GB/h Time required for 1 000 TB:

1 000 000 GB ÷ 45 000 GB/h ≈ 22.2 h ≈ 1 day

Using a 10 Gbps internet line increases the duration to roughly 10 days, while a residential broadband would take several months. The high monthly cost of a data‑center line makes it impractical for occasional transfers.

Physical “Human Courier” Alternative

Transporting the data on hard‑disk drives via high‑speed rail provides a much cheaper and comparable‑time solution.

Load sixteen 16 TB drives (total 256 TB) onto a train.

Train travel time Nanjing‑Beijing ≈ 5 h.

Additional handling and local transport ≈ 2 h.

Total door‑to‑door time ≈ 7 h, similar to a flight.

Cost estimate (2023 rates):

Round‑trip train ticket for cargo: 464 CNY × 2 = 928 CNY.

Taxi/local transport on both ends: ≈ 170 CNY.

Total ≈ 1 100 CNY, orders of magnitude lower than the monthly network lease.

Thus, for a one‑off transfer of several hundred terabytes, the “human courier” method is both faster and far cheaper than leasing a high‑capacity dedicated line.