Nextmini | A New Research Testbed for Network Emulation and Experimentation

Reference for dataplane startup inputs, node and network settings, runtime state, and lossless runtime configuration.

The dataplane configuration file (typically config.toml or node.toml) defines node-specific settings.

Startup CLI Inputs

Input	Default	Description
`CONTROLLER_ADDR` (positional)	unset	Optional positional override for `controller_addr`. When provided, it takes precedence over values from the config file and CLI flags.
`--config-path`	`config.toml`	Path to the dataplane config file loaded at startup (`config_path`).

Controller Connection

Field	Type	Default	CLI Flag	Description
`controller_addr`	`String`	`""`	`--controller-addr`	WebSocket address of the controller (for example, `ws://192.168.1.1:3000`). A plain `host:port` value is normalized to `ws://host:port`.
`controller_connect_timeout_ms`	`u64`	`5000`	(not exposed)	Timeout in milliseconds for the initial WebSocket connection to the controller. Config-file only.

Node Identity

Field	Type	Default	CLI Flag	Description
`node_id`	`usize`	`0`	`--node-id`	Unique node identifier (auto-assigned if 0).
`n_nodes`	`usize`	`1`	`--n-nodes`	Total number of dataplane nodes.
`node_id_offset`	`usize`	`0`	`--node-id-offset`	Offset added to computed node IDs (for namespace mode).

Network Interface Configuration

Field	Type	Default	CLI Flag	Description
`private_network_name`	`String`	`""`	`--private-network-name`	Shared private network identifier.
`private_network_interface`	`String`	`"eth0"`	`--private-network-interface`	Network interface for private network.
`private_network_addr`	`String`	`""`	`--private-network-addr`	Explicit IPv4 address for private network interface (auto-detected when empty).
`private_network_port`	`String`	`"8080"`	`--private-network-port`	Port for private network communication.
`public_network_interface`	`String`	`"eth0"`	`--public-network-interface`	Network interface for public network.
`public_network_addr`	`String`	`""`	`--public-network-addr`	Explicit IPv4 address for public network interface (auto-detected when empty).
`public_network_port`	`String`	`"8080"`	`--public-network-port`	Port for public network communication.
`tun_interface_name`	`String`	`"utun"`	`--tun-interface-name`	Name of the TUN interface.
`mtu`	`i32`	`1400`	`--mtu`	MTU of the TUN interface (max 6400).
`enable_local_interface`	`bool`	`true`	`--enable-local-interface`	Enable kernel TUN interface. Set to `false` when using Python API.

Processing Configuration

Field	Type	Default	CLI Flag	Description
`num_tun_queues`	`usize`	`1`	`--num-tun-queues`	Number of TUN queues.
`num_packet_processors`	`usize`	`0`	`--num-packet-processors`	Number of packet processors (0 = use CPU count).
`channel_capacity`	`usize`	`1000`	`--channel-capacity`	Capacity for channels between actors.
`queue_capacity`	`usize`	`1000`	`--queue-capacity`	Capacity of scheduler queues.
`channel_backpressure`	`bool`	`false`	`--channel-backpressure`	Apply backpressure instead of dropping when channels are full.

Protocol Configuration

Dataplane transport settings are documented in Transport Configuration, including CLI usage and examples for protocol and quic_congestion_control.

Scheduling Configuration

Field	Type	Default	CLI Flag	Description
`scheduler_type`	`SchedulingDiscipline`	`fifo`	`--scheduler-type`	Scheduler discipline: `fifo` or `wrr`.
`scheduler_drop_strategy`	`DropStrategy`	`taildrop`	`--scheduler-drop-strategy`	Drop strategy: `taildrop` or `red` (Random Early Detection).

Processing Mode

Field	Type	Default	CLI Flag	Description
`feature`	`Feature`	`sequential`	`--feature`	Processing mode: `sequential` (in-order) or `concurrent` (parallel, may reorder).
`operating_mode`	`OperatingMode`	`normal`	(from controller)	Operating mode: `normal` or `max`.

Runtime-populated Dataplane State

These fields are maintained at runtime and should not be treated as user tuning knobs.

Field	Runtime source
`local_address`	Computed from node identity and controller-provided base network settings.
`virtual_base_addr`	Received from controller startup configuration (`base_addr`).
`user_space_address`	Computed from node identity and user-space base network.
`external_base_addr`	Received from controller startup configuration (`external_base_addr`).
`local_netmask`	Received from controller startup configuration (`net_mask`).
`operating_mode`	Updated from controller node specifications.
`flow`	Updated from controller flow messages (`AddFlows`).
`max_server_port`	Received from controller startup configuration.

TCP Reordering Configuration

Field	Type	Default	CLI Flag	Description
`enforce_tcp_order`	`bool`	`true`	`--enforce-tcp-order`	Reorder TCP packets by sequence number before delivery.
`delay_tolerance`	`u64`	`500`	`--delay-tolerance`	Max microseconds to hold a flow waiting for missing TCP segment.
`backlog_tolerance`	`u64`	`0`	`--backlog-tolerance`	Max queued TCP packets before forcing delivery (0 = disabled).

User-Space Ports

Field	Type	Default	CLI Flag	Description
`user_space_client_port`	`u16`	`45535`	`--user-space-client-port`	User-space client port.
`user_space_server_port`	`u16`	`8888`	`--user-space-server-port`	User-space server port.

Metrics and Reconnection

Field	Type	Default	CLI Flag	Description
`metrics_collection_interval`	`u64`	`5`	`--metrics-collection-interval`	Metrics collection interval in seconds.
`restart_on_disconnect`	`bool`	`false`	`--restart-on-disconnect`	Restart node when connection to controller is lost.

Auto-Configuration (Namespace Mode)

Field	Type	Default	CLI Flag	Description
`auto_enable_ip_forward`	`bool`	`false`	`--auto-enable-ip-forward`	Automatically enable IPv4 forwarding.
`auto_add_forward_rules`	`bool`	`false`	`--auto-add-forward-rules`	Add FORWARD rules between namespace bridge and outbound interface.
`auto_add_nat`	`bool`	`false`	`--auto-add-nat`	Add MASQUERADE rule for namespace subnet.

Namespace Mode Configuration

These settings control multi-node deployment on a single machine using Linux namespaces.

Field	Type	Default	Description
`bridge_name`	`String`	`"isobr0"`	Linux bridge name for namespace isolation.
`bridge_ip`	`String`	`"172.16.8.1"`	IPv4 address for the bridge.
`subnet`	`u8`	`16`	Subnet mask length (CIDR).
`interval_between_spawn`	`u64`	`50`	Milliseconds between node creation.
`carrier_max_wait_ms`	`u64`	`20000`	Max wait time for veth interface carrier.
`carrier_poll_interval_ms`	`u64`	`100`	Poll interval for carrier checks.
`child_start_delay_ms`	`u64`	`150`	Delay after spawning child before handshake.
`handshake_timeout_ms`	`u64`	`25000`	Timeout for network setup handshake.

Lossless Session Configuration

See Lossless Session Configuration for the full configuration details, sample [lossless_runtime_config] block, and runtime Python interop notes.

Dataplane Configuration