NDTS Gateway Installation - Revision history

Mmaciejewski at 19:56, 9 June 2025

2025-06-09T19:56:56Z

← Older revision		Revision as of 19:56, 9 June 2025
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			{{NDTS_Navbox}}

	== Gateway Installation ==		== Gateway Installation ==

Mmaciejewski at 12:58, 4 June 2025

2025-06-04T12:58:38Z

← Older revision		Revision as of 12:58, 4 June 2025
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	== ~~'''~~Gateway Installation~~'''~~ ==		== Gateway Installation ==

	=== Prerequisites ===		=== Prerequisites ===
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	===== [[NDTS Gateway Update Example]] =====		===== [[NDTS Gateway Update Example]] =====

	== ~~'''~~NDTS Gateway Configuration~~'''~~ ==		== NDTS Gateway Configuration ==
	The following are optional configuration values that can be specified in the <code>/opt/nandt- gateway/gateway_configuration.json</code> file. The file must adhere to proper JSON formatting:		The following are optional configuration values that can be specified in the <code>/opt/nandt- gateway/gateway_configuration.json</code> file. The file must adhere to proper JSON formatting:

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	\|}		\|}

	== ~~'''~~NDTS Gateway Components~~'''~~ ==		== NDTS Gateway Components ==

	The NDTS Gateway consists of several key components installed under <code>/opt/nandt-gateway</code>, unless otherwise noted. Each plays a specific role in data transfer, configuration, or monitoring.		The NDTS Gateway consists of several key components installed under <code>/opt/nandt-gateway</code>, unless otherwise noted. Each plays a specific role in data transfer, configuration, or monitoring.
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	All other files int the <code>nandt-gateway</code> directory are for the operation of the gateway, and are not of general interest		All other files int the <code>nandt-gateway</code> directory are for the operation of the gateway, and are not of general interest

	== ~~'''~~Normal Operation of the Gateway~~'''~~ ==		== Normal Operation of the Gateway ==

	=== Experiment Data Flow ===		=== Experiment Data Flow ===
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	* When an NDTS daemon requests the user list, the gateway compares checksums; if they differ, it sends the current <code>users.dat</code> contents to the daemon		* When an NDTS daemon requests the user list, the gateway compares checksums; if they differ, it sends the current <code>users.dat</code> contents to the daemon

	== ~~'''~~NDTS Gateway Logging~~'''~~ ==		== NDTS Gateway Logging ==

	Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])		Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])

Mmaciejewski: /* NDTS Gateway Install Example */

2025-06-03T19:28:37Z

NDTS Gateway Install Example

← Older revision		Revision as of 19:28, 3 June 2025
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	Rolling back more than one version is not recommended.		Rolling back more than one version is not recommended.

	=== [[NDTS Gateway Install Example]] ===		=== Installation and Update Examples ===

			===== [[NDTS Gateway Install Example]] =====

			===== [[NDTS Gateway Update Example]] =====

	== '''NDTS Gateway Configuration''' ==		== '''NDTS Gateway Configuration''' ==

Mmaciejewski: /* Gateway Installation */

2025-06-03T19:21:29Z

Gateway Installation

← Older revision		Revision as of 19:21, 3 June 2025
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	Rolling back more than one version is not recommended.		Rolling back more than one version is not recommended.

			=== [[NDTS Gateway Install Example]] ===

	== '''NDTS Gateway Configuration''' ==		== '''NDTS Gateway Configuration''' ==

Mmaciejewski: /* NDTS Gateway Logging */

2025-06-03T19:16:02Z

NDTS Gateway Logging

Mmaciejewski: /* Experiment Data Flow */

2025-06-03T19:15:12Z

Experiment Data Flow

Mmaciejewski: /* NDTS Gateway Operation */

2025-06-03T19:12:21Z

NDTS Gateway Operation

← Older revision		Revision as of 19:12, 3 June 2025
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	All other files int the <code>nandt-gateway</code> directory are for the operation of the gateway, and are not of general interest		All other files int the <code>nandt-gateway</code> directory are for the operation of the gateway, and are not of general interest

	== '''~~NDTS~~ Gateway ~~Operation~~''' ==		== '''Normal Operation of the Gateway''' ==

	* ~~'''Experiment transfer''' – Workstation daemons connect~~ on ~~TCP 60195~~, ~~announce~~ a ~~dataset,~~ and ~~stream it~~ to <code>received/</code>. ~~Successful transfers spawn~~ a ~~'''~~Transmitter~~''' process that forwards~~ the ~~data~~ to the ~~receiver; on success the local copy is deleted~~.		=== Experiment Data Flow ===
	* ~~'''Retransmit''' – At start-~~up ~~and after each daemon heartbeat~~, ~~a '''Retransmitter''' scans~~ <code>~~received/~~</code>~~. If a dataset’s original retry window has expired, it launches a new transmitter until delivery succeeds or the file is manually removed~~.		* The gateway listens on its server port for connections from an NDTS daemon.
	* ~~'''Heartbeat forwarding''' – Every daemon heartbeat is wrapped with the gateway UUID, local and UTC timestamps~~, ~~then sent to~~ the ~~receiver by a short-lived '''Heartbeat Transmitter'''~~		* When a daemon indicates it has experiment data, the gateway opens a dedicated socket and saves the incoming files to the base output path (default <code>/opt/nandt-gateway/data/received</code>).
	* '''User list propagation''' – Every 15s the gateway requests an updated list from the ~~receiver~~; if the ~~checksum differs it saves~~ the ~~new list to <code>users.dat</code> and serves it to workstations on demand~~.		* After a complete, error-free transfer, the daemon marks the experiment as sent and will not resend it.
			* The gateway immediately spawns a Transmitter process—one per experiment—to forward the files to the NDTS Receiver.
			* A Transmitter retries up to <code>retry_limit</code> times, waiting <code>retry_delay</code> seconds between attempts.
			* On success, the experiment directory is deleted from the base output path; on exhaustion of retries the Transmitter exits and the data become eligible for Retransmit.

	----		=== Retransmit ===
			* At start-up and after each heartbeat (see below), the gateway launches a Retransmitter.
			* The Retransmitter scans <code>…/data/received</code> for unsent experiments.
			* For any experiment whose original retry window has elapsed, it spawns a new Transmitter and repeats the transmit workflow until success or manual deletion.
			* Before creating a Retransmitter, the gateway checks for <code>{base_output_path}/../retransmitter.pid</code>; if that PID is active, no new Retransmitter is started.

			=== Heartbeat Forwarding ===
			* The gateway does not send independent heartbeats.
			* Upon receiving a daemon heartbeat, it spawns a Heartbeat Transmitter that forwards the message to the NDTS Receiver, appending:
			* Local datetime
			* UTC datetime
			* Gateway UUID
			* If transmission fails, the heartbeat is dropped and the Heartbeat Transmitter exits.

			=== User-List Refresh ===
			* Every 15 s the gateway spawns a Refresh Users process to request an updated user list (users, samples, projects, studies, etc.) from the Receiver.
			* The request includes the checksum stored in <code>{base_output_path}/../user_checksum.dat</code>.
			* If the checksum is outdated, the Receiver returns a new list, which the gateway saves to <code>{base_output_path}/../users.dat</code> and updates the checksum file.
			* When an NDTS daemon requests the user list, the gateway compares checksums; if they differ, it sends the current <code>users.dat</code> contents to the daemon.

	== '''NDTS Gateway Logging''' ==		== '''NDTS Gateway Logging''' ==

Mmaciejewski at 18:32, 3 June 2025

2025-06-03T18:32:43Z

← Older revision		Revision as of 18:32, 3 June 2025
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	=== Prerequisites ===		=== Prerequisites ===
	* A '''Gateway UUID''' supplied by the NAN Repository administrator		* A '''Gateway UUID''' supplied by the NAN Repository administrator
	* A Linux host (Ubuntu 20.04 or later recommended) ~~reachable by all~~ workstations		* A Linux host (Ubuntu 20.04 or later recommended) that should be on the same network as the spectrometer workstations
	* TCP port '''60195''' open inbound from those workstations		* TCP port '''60195''' open inbound from those workstations

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	</pre>		</pre>

	=== Firewall ~~Note~~ ===		=== Firewall ===
	Open port 60195 to ~~each NDTS workstation~~; no other inbound ports are required.		Open TCP port 60195 on the Gateway to all spectrometer workstations; no other inbound ports are required.

	=== Verifying the Service ===		=== Verifying the Service ===
	<pre>		Note that the installer automatically runs <code>systemctl start data-transport-gateway</code> after installation, but it is always good to check when installing the software that the service started.<pre>
	sudo systemctl status data-transport-gateway # should show “active (running)”		sudo systemctl status data-transport-gateway # should show “active (running)”
	sudo systemctl start data-transport-gateway # start if not running		sudo systemctl start data-transport-gateway # start if not running
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	=== Updating the Gateway ===		=== Updating the Gateway ===
	<pre>		When installing the Gateway software the installation will auto-detect if another version exists. The installation will proceed as above, but without questions as it will find the previous configuration file and use those values.<pre>
	# Run the same installer script from a newer package		# Run the same installer script from a newer package
	cd dtgateway-installer		cd dtgateway-installer
	sudo ./install.sh # auto-detects an existing install; no prompts		sudo ./install.sh # auto-detects an existing install; no prompts
	</pre>~~Follow~~ the ~~directions above for verifying the service~~ after ~~updating~~ the ~~Gateway to ensure~~ that the service ~~is running~~.		</pre>Note that the installer automatically runs <code>systemctl restart data-transport-gateway</code> after upgrading, but it is always good to check when installing the software that the service started. See Verifying the Service for details

	=== Uninstalling the Gateway ===		=== Uninstalling the Gateway ===
	<pre>		Download the latest version of the Gateway software, unpack, and run the uninstall.sh script<pre>
	sudo ./uninstall.sh # script is included inside every package		sudo ./uninstall.sh # script is included inside every package
	</pre>		</pre>

	=== Rolling Back the Gateway ===		=== Rolling Back the Gateway ===
	Obtain the desired older package and run its <code>install.sh</code>.		Obtain the desired older package and run its <code>install.sh</code>
	Rolling back more than one ~~or two versions~~ is not recommended.
			Rolling back more than one version is not recommended.

	== '''NDTS Gateway Configuration''' ==		== '''NDTS Gateway Configuration''' ==
	The following are optional configuration values that can be specified in the /opt/nandt- gateway/gateway_configuration.json file. The file must adhere to proper JSON formatting:		The following are optional configuration values that can be specified in the <code>/opt/nandt- gateway/gateway_configuration.json</code> file. The file must adhere to proper JSON formatting:

	=== Configuration Options ===		=== Configuration Options ===
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	\|		\|
	\|}		\|}

	~~== '''NDTS Gateway Components''' ==~~

	~~All files reside under <code>/opt/nandt-gateway</code> unless noted. :contentReference[oaicite:1]{index=1}~~

	* <code>main.py</code> – entry point for the Python service
	* <code>/etc/systemd/system/data-transport-gateway.service</code> – systemd unit file
	* <code>nan-gateway.log</code> – runtime log (path overridable via <code>log_file_path</code>)
	* <code>gateway_configuration.json</code> – configuration described above
	* <code>data/</code>
	** <code>received/</code> – transient storage for incoming experiment data
	** <code>retransmitter.pid</code> – PID of the active retransmitter helper
	** <code>users.dat</code> – current user / sample / project list
	** <code>user_checksum.dat</code> – checksum that governs list refreshes

	== '''NDTS Gateway Components''' ==		== '''NDTS Gateway Components''' ==
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	{\| class="wikitable"		{\| class="wikitable"
	\|+ ~~Gateway component files and their functions~~		\|+
	! File or Directory !! Description		! File or Directory !! Description
	\|-		\|-
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	\| <code>data/user_checksum.dat</code> \|\| Checksum file used to determine when the users.dat file should be refreshed		\| <code>data/user_checksum.dat</code> \|\| Checksum file used to determine when the users.dat file should be refreshed
	\|}		\|}
	All other files int he nandt-gateway directory are for the operation of the gateway, and are not of general interest		All other files int the <code>nandt-gateway</code> directory are for the operation of the gateway, and are not of general interest

	== '''NDTS Operation''' ==		== '''NDTS Gateway Operation''' ==

	* '''Experiment transfer''' – Workstation daemons connect on TCP 60195, announce a dataset, and stream it to <code>received/</code>. Successful transfers spawn a '''Transmitter''' process that forwards the data to the receiver; on success the local copy is deleted.		* '''Experiment transfer''' – Workstation daemons connect on TCP 60195, announce a dataset, and stream it to <code>received/</code>. Successful transfers spawn a '''Transmitter''' process that forwards the data to the receiver; on success the local copy is deleted.
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	----		----

	== '''NDTS Logging''' ==		== '''NDTS Gateway Logging''' ==

	Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])		Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])

Mmaciejewski: /* NDTS Logging */

2025-06-03T16:05:31Z

NDTS Logging

← Older revision		Revision as of 16:05, 3 June 2025
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	</pre> From the log file note:		</pre> From the log file note:

	* The first ~~message shows~~ the spawning of the retransmitter~~. The subsequent lines that contain “INFO GatewayRetransmitter” after the timestamp show that there are no experiments to retransmit, so the retransmitter just exits~~.		* The first three lines show the spawning of the retransmitter.
	* The line that starts with “INFO GatewayReceiver” ~~after the timestamp~~ shows the file receiver starting, which means that it is awaiting connects from NDTS Daemons.		* The line that starts with “INFO GatewayReceiver” shows the file receiver starting, which means that it is awaiting connects from NDTS Daemons.
	* The last ~~lines~~ shows that a heartbeat came in from an NDTS Daemon, and the Gateway is forwarding it to the Receiver.		* The lines that contain “INFO GatewayRetransmitter” show that there are no experiments to retransmit, so the retransmitter exits.
			* The last line shows that a heartbeat came in from an NDTS Daemon, and the Gateway is forwarding it to the Receiver.

Mmaciejewski: /* NDTS Logging */

2025-06-03T15:25:53Z

NDTS Logging

← Older revision		Revision as of 15:25, 3 June 2025
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	== '''NDTS Operation''' ==		== '''NDTS Operation''' ==

	* '''Experiment transfer''' – Workstation daemons connect on TCP 60195, announce a dataset, and stream it to <code>received/</code>. Successful transfers spawn a Transmitter process that forwards the data to the receiver; on success the local copy is deleted. ~~:contentReference[oaicite:2]{index=2}~~		* '''Experiment transfer''' – Workstation daemons connect on TCP 60195, announce a dataset, and stream it to <code>received/</code>. Successful transfers spawn a '''Transmitter''' process that forwards the data to the receiver; on success the local copy is deleted.
	* '''Retransmit''' – At start-up and after each daemon heartbeat, a Retransmitter scans <code>received/</code>. If a dataset’s original retry window has expired, it launches a new ~~Transmitter~~ until delivery succeeds or the file is manually removed.		* '''Retransmit''' – At start-up and after each daemon heartbeat, a '''Retransmitter''' scans <code>received/</code>. If a dataset’s original retry window has expired, it launches a new transmitter until delivery succeeds or the file is manually removed.
	* '''Heartbeat forwarding''' – Every daemon heartbeat is wrapped with the gateway UUID, local and UTC timestamps, then sent to the receiver by a short-lived Heartbeat Transmitter.		* '''Heartbeat forwarding''' – Every daemon heartbeat is wrapped with the gateway UUID, local and UTC timestamps, then sent to the receiver by a short-lived '''Heartbeat Transmitter'''
	* '''User list propagation''' – Every ~~15 s~~ the gateway requests an updated list from the receiver; if the checksum differs it saves the new list to <code>users.dat</code> and serves it to workstations on demand.		* '''User list propagation''' – Every 15s the gateway requests an updated list from the receiver; if the checksum differs it saves the new list to <code>users.dat</code> and serves it to workstations on demand.

	----		----
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	== '''NDTS Logging''' ==		== '''NDTS Logging''' ==

	Logging level is controlled by the ~~<code>"~~logging_level~~"</code> key~~ in ~~<code>gateway_configuration.json</code>.~~		Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])
	~~Levels~~ (~~high → low volume~~)~~: <code>fatal</code>, <code>error</code>, <code>warning</code>, <code>info</code>, <code>debug</code>.~~
	~~Default is <code>info</code>. The log file path defaults to <code>/opt/nandt-gateway/nan-gateway.log</code>~~

	Example log excerpt:		Example log excerpt:

	<pre>2022-06-06 09:22:23,130 INFO main [61393]: Starting gateway retransmitter instance...		<pre>2022-06-06 09:22:23,130 INFO main [61393]: Starting gateway retransmitter instance...
			2022-06-06 09:22:23,130 INFO main [61393]: Experiment file path = /opt/nandt-gateway/data/received
	2022-06-06 09:22:23,132 INFO main [61393]: Starting gateway receiver network endpoint...		2022-06-06 09:22:23,132 INFO main [61393]: Starting gateway receiver network endpoint...
			2022-06-06 09:22:23,133 INFO GatewayReceiver [61393]: Starting file receiver...
			2022-06-06 09:22:23,133 INFO GatewayRetransmitter [61405]: In GatewayRetransmit handle() method...
			2022-06-06 09:22:23,134 INFO GatewayRetransmitter [61405]: No experiments to retransmit -- exiting...
			2022-06-06 09:22:23,134 INFO GatewayRetransmitter [61405]: GatewayRetransmit handle() method completed...
	2022-06-06 09:23:12,829 INFO GatewayTransmitter [61512]: Heartbeat sent to https://receiver.usnan.org/heartbeat		2022-06-06 09:23:12,829 INFO GatewayTransmitter [61512]: Heartbeat sent to https://receiver.usnan.org/heartbeat
	</pre> :~~contentReference[oaicite:4]{index=4}~~		</pre> From the log file note:

			* The first message shows the spawning of the retransmitter. The subsequent lines that contain “INFO GatewayRetransmitter” after the timestamp show that there are no experiments to retransmit, so the retransmitter just exits.
			* The line that starts with “INFO GatewayReceiver” after the timestamp shows the file receiver starting, which means that it is awaiting connects from NDTS Daemons.
			* The last lines shows that a heartbeat came in from an NDTS Daemon, and the Gateway is forwarding it to the Receiver.

← Older revision		Revision as of 19:16, 3 June 2025
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	Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])		Logging level are controlled by the logging_level parameter in the JSON configuration file (see [[NDTS Gateway Installation#Configuration Options\|above]])

	Example log excerpt:		=== Example log excerpt: ===

	<pre>2022-06-06 09:22:23,130 INFO main [61393]: Starting gateway retransmitter instance...		<pre>2022-06-06 09:22:23,130 INFO main [61393]: Starting gateway retransmitter instance...
	2022-06-06 09:22:23,130 INFO main [61393]: Experiment file path = /opt/nandt-gateway/data/received		2022-06-06 09:22:23,130 INFO main [61393]: Experiment file path = /opt/nandt-gateway/data/received
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	2022-06-06 09:22:23,134 INFO GatewayRetransmitter [61405]: GatewayRetransmit handle() method completed...		2022-06-06 09:22:23,134 INFO GatewayRetransmitter [61405]: GatewayRetransmit handle() method completed...
	2022-06-06 09:23:12,829 INFO GatewayTransmitter [61512]: Heartbeat sent to https://receiver.usnan.org/heartbeat		2022-06-06 09:23:12,829 INFO GatewayTransmitter [61512]: Heartbeat sent to https://receiver.usnan.org/heartbeat
	</pre> ~~From the log file note:~~		</pre>

			==== From the log file note: ====
	* The first three lines show the spawning of the retransmitter.		* The first three lines show the spawning of the retransmitter.
	* The line that starts with “INFO GatewayReceiver” shows the file receiver starting, which means that it is awaiting connects from NDTS Daemons.		* The line that starts with “INFO GatewayReceiver” shows the file receiver starting, which means that it is awaiting connects from NDTS Daemons.
	* The lines that contain “INFO GatewayRetransmitter” show that there are no experiments to retransmit, so the retransmitter exits.		* The lines that contain “INFO GatewayRetransmitter” show that there are no experiments to retransmit, so the retransmitter exits.
	* The last line shows that a heartbeat came in from an NDTS Daemon, and the Gateway is forwarding it to the Receiver.		* The last line shows that a heartbeat came in from an NDTS Daemon, and the Gateway is forwarding it to the Receiver.

← Older revision		Revision as of 19:15, 3 June 2025
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	=== Experiment Data Flow ===		=== Experiment Data Flow ===
	* The gateway listens on its server port for connections from an NDTS daemon.		* The gateway listens on its server port for connections from an NDTS daemon
	* When a daemon indicates it has experiment data, the gateway opens a dedicated socket and saves the incoming files to the base output path (default <code>/opt/nandt-gateway/data/received</code>).		* When a daemon indicates it has experiment data, the gateway opens a dedicated socket and saves the incoming files to the base output path (default <code>/opt/nandt-gateway/data/received</code>)
	* After a complete, error-free transfer, the daemon marks the experiment as sent and will not resend it.		* After a complete, error-free transfer, the daemon marks the experiment as sent and will not resend it
	* The gateway immediately spawns a Transmitter process—one per experiment—to forward the files to the NDTS Receiver.		* The gateway immediately spawns a '''Transmitter process'''—one per experiment—to forward the files to the NDTS Receiver
	* A Transmitter retries up to <code>retry_limit</code> times, waiting <code>retry_delay</code> seconds between attempts.		* A Transmitter retries up to <code>retry_limit</code> times, waiting <code>retry_delay</code> seconds between attempts
	* On success, the experiment directory is deleted from the base output path; on exhaustion of retries the Transmitter exits and the data become eligible for Retransmit.		* On success, the experiment directory is deleted from the base output path; on exhaustion of retries the Transmitter exits and the data become eligible for '''Retransmit'''

	=== Retransmit ===		=== Retransmit ===
	* At start-up and after each heartbeat (see below), the gateway launches a Retransmitter.		* At start-up and after each heartbeat (see below), the gateway launches a '''Retransmitter'''
	* The Retransmitter scans <code>…/data/received</code> for unsent experiments.		* The Retransmitter scans <code>…/data/received</code> for unsent experiments
	* For any experiment whose original retry window has elapsed, it spawns a new Transmitter and repeats the transmit workflow until success or manual deletion.		* For any experiment whose original retry window has elapsed, it spawns a new Transmitter and repeats the transmit workflow until success or manual deletion
	* Before creating a Retransmitter, the gateway checks for <code>{base_output_path}/../retransmitter.pid</code>; if that PID is active, no new Retransmitter is started.		* Before creating a Retransmitter, the gateway checks for <code>{base_output_path}/../retransmitter.pid</code>; if that PID is active, no new Retransmitter is started

	=== Heartbeat Forwarding ===		=== Heartbeat Forwarding ===
	* The gateway does not send independent heartbeats.		* The gateway does not send independent heartbeats
	* Upon receiving a daemon heartbeat, it spawns a Heartbeat Transmitter that forwards the message to the NDTS Receiver, appending:		* Upon receiving a daemon heartbeat, it spawns a '''Heartbeat Transmitter''' that forwards the message to the NDTS Receiver, appending:
	* Local datetime		* Local datetime
	* UTC datetime		* UTC datetime
	* Gateway UUID		* Gateway UUID
	* If transmission fails, the heartbeat is dropped and the Heartbeat Transmitter exits.		* If transmission fails, the heartbeat is dropped and the Heartbeat Transmitter exits

	=== User-List Refresh ===		=== User-List Refresh ===
	* Every 15 s the gateway spawns a Refresh Users process to request an updated user list (users, samples, projects, studies, etc.) from the Receiver.		* Every 15 seconds the gateway spawns a '''Refresh Users''' process to request an updated user list (users, samples, projects, studies, etc.) from the Receiver
	* The request includes the checksum stored in <code>{base_output_path}/../user_checksum.dat</code>.		* The request includes the checksum stored in <code>{base_output_path}/../user_checksum.dat</code>
	* If the checksum is outdated, the Receiver returns a new list, which the gateway saves to <code>{base_output_path}/../users.dat</code> and updates the checksum file.		* If the checksum is outdated, the Receiver returns a new list, which the gateway saves to <code>{base_output_path}/../users.dat</code> and updates the checksum file
	* When an NDTS daemon requests the user list, the gateway compares checksums; if they differ, it sends the current <code>users.dat</code> contents to the daemon.		* When an NDTS daemon requests the user list, the gateway compares checksums; if they differ, it sends the current <code>users.dat</code> contents to the daemon

	== '''NDTS Gateway Logging''' ==		== '''NDTS Gateway Logging''' ==