1. Introduction

The IFW RTMS Tools package bundles the maintained RTMS sender and receiver utilities along with their supporting libraries. The current stack targets llnetio, which supplies the UDP, MUDPI and RTMS layers used across IFW pipelines. Older MUDPI/RTMS implementations remain in the tree for migration support but are deprecated. RTMS Tools is using the features provided by the IFW RTMS Lib project.

This manual serves developers working with RTMS applications and can assist in testing and troubleshooting RTMS applications.

Purpose and scope

RTMS Tools delivers utilities for RTMS image transfer:

  • RTMS Sender: replays FITS cubes over RTMS with configurable topics, MTU, pacing and extended header modes.

  • RTMS Receiver: monitors RTMS topics, receives the MUDPI/RTMS samples, gathers per-sample statistics, and can publish frames to DDT.

  • DDT interface classes: rtms2ddtlib_llnetio bridges RTMS receivers to DDT streams with queueing, geometry validation and reconnect handling.

RTMS Tools builds on the ifw-rtmslib library (which itself relies on llnetio) for the core sender/receiver functionality. Refer to the ifw-rtmslib user manual for the underlying RTMS API and extended info handling.

Transition status

We are in the process of migrating from the legacy MUDPI/RTMS libraries to the llnetio-based implementations. The legacy stack is still available but deprecated and will be removed in the near future.

  • rtmslib_llnetio and the rtmssender / rtmsreceiver_llnetio utilities are the supported stack.

  • rtms2ddtlib_llnetio implements the gateway that pushes RTMS frames to DDT and is aligned with the llnetio code base.

  • Legacy directories (rtmslib, rtmsreceiver, rtms2ddtlib) still build but are no longer maintained; prefer the llnetio equivalents for new work.

Manual outline

  1. Introduction and conventions.

  2. Repository overview.

  3. API synopsis for the key C++ classes.

  4. User guide for the command line utilities.

  5. Practical examples.

Conventions

  • Namespaces are written as ifw::rtmstools::*.

  • ${INTROOT} refers to the installation prefix produced by waf.

  • Command snippets rely on the rtmssender and rtmsreceiver binaries generated by ./waf unless stated otherwise.

Acronyms

Acronym

Description

BPP

Bytes Per Pixel

DDT

Data Display Tool

FITS

Flexible Image Transport System

IFW

Instrument Framework

MTU

Maximum Transmission Unit

MUDPI

Multicast UDP Interface

RTMS

Real-Time MUDPI Stream

SDK

Software Development Kit

UDP

User Datagram Protocol

YAML

YAML Ain’t Markup Language

Nomenclature

Term

Description

RTMS Sample

One complete transfer composed of a leader, payload packets and a trailer.

Extended Info

Optional leader extension carrying timestamp, datatype and image geometry.

Topic ID

Identifier used by RTMS to match publishers and subscribers on the wire.

Leader / Payload / Trailer

RTMS packet types framing a sample; the leader may include extended info.

Extended Info Mode

Contract deciding whether the leader carries nothing, only a timestamp or the full image metadata block.

Publisher

Process that sends RTMS samples (for example rtmstoolsSender).

Subscriber

Process that receives RTMS samples (for example rtmstoolsReceiver or the RTMS to DDT gateway).

Geometry

Width, height and offsets used to interpret the pixel payload.