Pathport

showstack / protocols / pathport

Also called Pathport Protocol, Pathway Pathport.

Pathway Connectivity's own DMX-over-ethernet protocol, used by Pathport gateways for data and for the discovery and configuration that Pathscape depends on. Most modern jobs run sACN or Art-Net through the same boxes and only meet Pathport when setting them up.

Lighting controlProprietaryPathway ConnectivityReported

Stewarded by Pathway Connectivity (Acuity Brands).

Control Small, urgent, must arrive

Small messages that either repeat constantly or fire once. Bandwidth is almost never the problem.

What kills it. Latency and loss on the messages that fire once. A repeating level survives a dropped packet; a GO does not.

The four flows, and why the model is worth having →

Ports

udp/3792 Pathport data, ARP-style node discovery, and configuration
0x0ED0. Taken from the Open Lighting Architecture implementation; Pathway does not publish the protocol.

Multicast

239.255.237.1 (data)
239.255.237.2 (configuration)
239.255.237.255 (status)
Group addresses as implemented by the Open Lighting Architecture Pathport plugin. Nodes are also addressed individually by a 32-bit Pathport device ID, with 0xFFFFFFFF used as a broadcast ID.

Addressing

A flat xDMX channel space rather than numbered universes: channels 0-511 are the first universe, 512-1023 the second. OLA notes the spec says 64 universes while devices appear to support up to 128.

What goes wrong

Pathway does not publish the protocol. The only public description is the Open Lighting Architecture plugin source, so treat any third-party implementation as best effort and test it against the actual firmware.

Addressing is a flat xDMX channel space, not universes. Console universe 2 is xDMX channels 512-1023, so a one-universe offset here shifts an entire rig by 512 slots rather than by one fixture.

Node discovery uses a Pathport ARP request and reply, not IP ARP. A gateway that does not answer is not necessarily offline; it may be on a different multicast group or filtered out by IGMP snooping.

If Pathscape cannot see a gateway that is visibly passing data, look at multicast and IGMP snooping on the switch before assuming a device fault. Data and configuration ride different groups.

Pathport gateways also accept sACN, Art-Net, ETCNet2, ETCNet3 and Strand ShowNet, and will take several at once. It is easy to create an accidental merge that only shows up when the second console is patched.

What speaks Pathport (3)

Product	Direction	Notes
ChamSys MagicQ ChamSys	bidirectional	Pathport output, and received for capture or merging. Unusual for a non-Pathway console.
OLA (Open Lighting Architecture) Open Lighting Project	bidirectional	Listed as the Pathway Pathport plugin.
Pathway Connectivity Pathport OCTO Pathway Connectivity	bidirectional	Pathway's own protocol.

Open source implementations

OLA (Open Lighting Architecture) — C++, LGPL-2.1-or-later

Typical use

Pathport gateway data and configuration on Pathway networks
Pathscape discovery and setup of DMX/RDM gateways
Legacy installs that predate widespread sACN deployment
Mixed networks where Pathway boxes sit alongside ETCNet and ShowNet sources

Sources

OLA Pathport plugin — PathportNode.h (PATHPORT_PORT 0xed0, data/config/status multicast groups, broadcast ID) — Open Lighting Project
OLA Pathport plugin README (xDMX flat channel space, universe mapping) — Open Lighting Project
Pathport DMX Management System Specification, C Series Nodes (protocol list including Pathport Protocol) — Pathway Connectivity primary
Pathport DMX Ethernet Gateways product family (Pathscape configuration) — Pathway Connectivity / Acuity Brands primary

Understand the mechanism

DMX on the wire Show networks

Something wrong, or missing?

Known gaps on this entry: first_published. If you can source one of them, that is a ten minute pull request.

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