Test the path in layers.
Confirm local interface and subnet, route to the IED, TCP reachability on port 102, then inspect the MMS association response. Stop changing SCL files until the transport path is proven.
Routing · TCP · association · endpoint
Port 102 failure must be separated into network and MMS layers.
A ping response does not prove the IEC 61850 server is reachable, and an open TCP socket does not prove the MMS association will succeed.
- ping works but TCP 102 times out
- TCP opens then association is rejected or closed
- another engineering laptop connects but this one cannot
- the configured IP differs from the live device address
- connection works on one interface but not another
Diagnostic path
Find the first layer that fails.
Changing multiple network and application settings at once destroys useful evidence. Record the selected interface, local address, target address, port and exact failure stage.
Validate endpoint identity
Confirm IP address, subnet mask, gateway assumptions and that the selected relay or simulator is the intended device.
Validate the local interface
Disable accidental Wi-Fi or VPN routing paths only within the approved test procedure and bind to the correct engineering NIC.
Validate TCP port 102
Distinguish timeout, refusal and immediate close. Each points to a different network or service state.
Inspect association evidence
If TCP succeeds, retain the MMS or presentation-layer rejection instead of reporting only “connection failed.”
Keep the failure stage visible
ARSAS diagnostics help distinguish endpoint, association, service and device behavior inside the originating IED session.
Related pages
After connection succeeds, validate the live model.
Use the MMS Client workflow and compare live evidence with the configured SCL context.
Use the evidence to narrow the cause—not to claim conformance.
ARSAS can expose live model, report, GOOSE, file, control and diagnostic evidence. Final conclusions still depend on the approved project design, vendor documentation, test procedure, network access and independent verification.
Written and reviewed by Ari Sulistiono.
Reviewed 20 July 2026 for practical IEC 61850 laboratory, FAT, SAT, commissioning and troubleshooting use.
Verified stable release
Download ARSAS 1.6.17 for Windows.
Use the installer for a normal workstation, choose the portable ZIP for a controlled folder deployment, and verify the published SHA-256 before use.
What’s new, limitations and signing status →