Limits and Performance

This appendix documents hard limits, configurable bounds, and observed performance characteristics of the peeroxide-cli tools.

Hard Limits

Constant	Value	Context
`MAX_ECHO_SESSIONS`	64	Concurrent echo sessions per `announce` process
`HANDSHAKE_TIMEOUT`	5 s	Echo protocol handshake timeout
`IDLE_TIMEOUT`	30 s	Echo session idle timeout
`ECHO_MSG_LEN`	16 bytes	Echo probe frame size (fixed)
`ECHO_TIMEOUT` (ping)	5 s	Per-probe timeout in `ping --connect` mode
`MAX_CHUNKS`	65 535	Maximum chunks in a single `deaddrop` message
`MAX_PAYLOAD`	1 000 bytes	Maximum payload per `deaddrop` chunk
`ROOT_HEADER_SIZE`	39 bytes	`deaddrop` root chunk header size
`NON_ROOT_HEADER_SIZE`	33 bytes	`deaddrop` non-root chunk header size
`CHUNK_SIZE` (cp)	65 536 bytes	`cp` file chunk size
`--data` max (announce)	1 000 bytes	Maximum `--data` payload for `announce`
lookup `--with-data` concurrency	16	`buffer_unordered(16)` for mutable DHT gets
ping topic mode peer cap	20	Maximum peers probed per topic lookup

Derived Limits

Maximum deaddrop message size:

MAX_CHUNKS × MAX_PAYLOAD = 65 535 × 1 000 = ~65.5 MB

Practical limit is lower due to DHT value size constraints and network latency.

Maximum cp file size:

Limited by available DHT storage and client memory. Each 65 536-byte chunk is stored as a separate immutable DHT value. There is no hard-coded upper bound in the CLI, but very large files will require many round-trips.

Timing

Parameter	Value	Notes
`announce` refresh interval	600 s	Background mutable put to keep slot alive
`announce` seq	Unix epoch seconds	Two refreshes in the same second produce identical seq — see ISSUES.md
`ping --interval` default	1.0 s	Configurable
`ping --count` default	1	0 = infinite

Concurrency

lookup --with-data fetches peer data in parallel with a concurrency window of 16 (buffer_unordered(16)).
announce handles incoming connections concurrently; echo sessions are bounded by MAX_ECHO_SESSIONS = 64.
cp uploads/downloads chunks sequentially per file (parallelism may be added in future releases).

Exit Codes

Code	Meaning	Tools
0	Success / clean shutdown	all tools
1	Fatal error	all tools
130	SIGINT received	`lookup`, `ping`
0	SIGINT/SIGTERM received	`announce` (intentional — clean shutdown is success)

Note: announce returns 0 on SIGINT/SIGTERM because interactive shutdown is the normal workflow. lookup and ping return 130 to allow callers to distinguish interruption from success.