# `MqttX.Transport.ThousandIsland`
[🔗](https://github.com/cignosystems/mqttx/blob/v0.11.2/lib/mqttx/transport/thousand_island.ex#L1)

ThousandIsland transport adapter for MqttX.

This adapter uses ThousandIsland as the underlying TCP/TLS server.

## Usage

    MqttX.Server.start_link(MyHandler, handler_opts,
      transport: MqttX.Transport.ThousandIsland,
      port: 1883
    )

## Options

- `:port` - Port to listen on (default: 1883)
- `:ip` - IP address to bind to (default: `{0, 0, 0, 0}`)
- `:transport_module` - ThousandIsland transport module
  (`ThousandIsland.Transports.TCP` or `...SSL`)
- `:transport_options` - SSL/TLS options when using the SSL transport,
  merged over a secure baseline (TLS 1.2/1.3, `secure_renegotiate`)
- `:num_acceptors` - Number of acceptor processes (default: 100)
- `:read_timeout` - ThousandIsland socket read timeout (default:
  `:infinity`). MQTT liveness is enforced by the protocol keepalive and
  `:max_idle_timeout` below; TI's own 60 s default would disconnect
  spec-compliant clients whose Keep Alive exceeds it.

Everything below is passed through `transport_opts` to the protocol handler
and applies to all adapters:

- `:max_packet_size` - Reject packets whose declared size exceeds this,
  before the body is buffered (default: 1 MiB, `:infinity` disables)
- `:max_idle_timeout` - Close a socket idle for this long regardless of the
  negotiated Keep Alive, which does not apply when a client connects with
  `keep_alive: 0` (default: 900_000 ms, `:infinity` disables)
- `:connect_timeout` - Close a socket that has not completed CONNECT within
  this window (default: 10_000 ms, `:infinity` disables)
- `:max_retained_messages` - Cap on distinct retained topics
  (default: 100_000, `:infinity` disables)
- `:rate_limit` - Options for `MqttX.Server.RateLimiter` (default: none)
- `:receive_maximum` - Inbound QoS > 0 flow-control window (default: 65535)
- `:topic_alias_maximum` - Topic aliases the server accepts (default: 100)
- `:server_keep_alive` - Override the client's Keep Alive (MQTT 5.0 only)
- `:supported_versions` - Accepted protocol levels (default: `[3, 4, 5]`)
- `:qos2_retry_interval` / `:qos2_max_retries` - Outbound QoS 1/2
  retransmission tuning (defaults: 5000 ms, 3)

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*Consult [api-reference.md](api-reference.md) for complete listing*