Packet loss

How it works

TCP retransmits. Throughput collapses as loss rises. A 1 percent loss can turn a 100 Mbps path into a slow one for a single flow. Parallel flows and QUIC's stream isolation change the shape of the damage. They do not remove the need to retransmit.

A 10 GB transfer estimated at 15 minutes runs 90 minutes. Loss on the WAN is 0.8 percent. A later window with clean loss finishes in 18 minutes. The file was never the variable.

How it differs

Packet loss is not throttling. A throttle is smooth. Loss is retransmission and delay.

Wifi interference looks like loss. Moving the radio can beat buying bandwidth.

Measure loss before you resize the file.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For packet loss, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive packet loss files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.