Java implementation for the CCSDS SLE (Space Link Extension) protocol.

Currently implemented services are:

• Forward CLTU Service
• Return All Frame Service
• Return Channel Frame Service

Both user (client) and provider(server) are implemented.

There is also a SLE to UDP bridge which implements a standalone SLE provider useful as frontend for a simulator. See below.

This library is independent from Yamcs; it's only dependencies are

• netty used to implement the network communication
• ASN.1 library jasn1 used to encode/decode the SLE messages.

The yamcs-sle package is based on this library and offers data links implementation that allow Yamcs to connect to SLE.

TODO: add some automated tests

SLE to UDP bridge

The SLE to UDP bridge is useful for testing a SLE connection to an existing simulator in a setup like this:

MCS with SLE (e.g. Yamcs) <--- RAF/RCF/FCLTU SLE --> SleUdpBridge <---- CLTU/AOS|TM frames/UDP ----> Simulator

The configuration is in bridge.properties. logging.properties can be adjusted to increase the logging at SLE level.

To start the bridge, please launch the script: ./udp-sle-bridge.sh

Known Problems and Limitations of the SLE to UDP bridge

• The bridge only implements online complete RAF or RCF delivery mode
• RCF works effectively as RAF, no filtering on VCID is performed by the provider
• Two different clients can bind the the same Service, but starting the RAF or RCF will fail for the second client because it will start a second UDP server on the same port