Protocol — Client ↔ Server ​

This is the binary frame protocol that the lock server and clients exchange over TCP. Every official client implements this specification identically, byte for byte. See each message's Structure (field layout) and Example (actual bytes sent, changes with refresh) on the pages below.

Byte notation: op is shown as an ASCII character (e.g. A); wait, lease, and token are binary, so they're shown in hex (big-endian) (e.g. wait=5 → 00 05). key and addr are UTF-8 text, and reason is ASCII text — all of these are variable-length, shown as N in the structure. The trailing \n (newline) terminates the frame as 0A. Fields are sent back-to-back with no delimiter.

Table of Contents ​

• Transport layer
• Requests
  • A · Acquire
  • R · Release
• Responses
  • A · Acquired
  • T · Timeout
  • R · Released
  • N · Not found
  • E · Error
  • M · Moved
• Field constraints
• Request × key-state matrix
• Fencing tokens
• Response matching rules
• Example session

The server-to-server cluster replication protocol is covered on a separate page.