Signal Routing Reference

Overview

This reference defines the hi signal model and routing behavior. It covers the three Layers, routing entities, and Signal Paths. Use it to understand how Ports, Port Containers, and Portals participate in routing.

For topic-specific introductions, see Layers, Port Containers, and Portals.

How hi Models Signals: Three Layers

hi models every installation on the Physical, Flow, and Essence Layers. Routing happens at the Flow Layer, where Port Containers and Portals also operate, and Tally is associated with Essence Ports. See Layers for the model.

Three Layers Showing Physical, Flow, and Essence

Ports

A Flow Port represents one routable signal on a Node. A Flow Port can carry multiple Essences. Operators connect a Source to a Destination, and the hi system resolves the corresponding routing entities.

Attribute	Description
Direction	Input Output or BiDirectional
Format Type	The signal format carried by this Port such as SDI Audio or NDI^®
Medium	Baseband or IP

A Port belongs to a Node. The Node can represent a physical device, software service, or logical component.

Format Types

The format type determines what kind of signal a Port carries and enforces compatibility rules during routing.

Category	Type in the Interface	Description
Baseband	SDI	Serial Digital Interface
Baseband	Audio	Analog or digital audio
Baseband	GPIO	General Purpose I/O
Baseband	Data	Generic data
Network	NDI	NDI network video
Network	AMPP Stream	GV AMPP streaming format
SMPTE IP	ST2022-8	ST 2022-6 streams synchronized within an ST 2110-10 system
SMPTE IP	ST2110-20	Uncompressed video over IP
SMPTE IP	ST2110-30	Audio over IP (AES67)
SMPTE IP	ST2110-40	Ancillary data over IP
Compressed	Compressed V	Compressed video stream
Compressed	Compressed A	Compressed audio stream
Compressed	Compressed D	Compressed data stream

Connection rule: Two Ports can only connect if their format types match exactly (for example, SDI to SDI or Audio to Audio). Mismatched formats are blocked.

Information

Note that the format type describes the Flow Layer transport, not the essences inside. An SDI Port and an ST 2110-20 Port both carry video, but they use different transports and cannot be directly connected without conversion.

Port Containers

A Port Container is a named, ordered group of Ports that acts as a single routing entity. See Port Containers for the model and Audio Shuffling for reordering slots at routing time.

Key Attributes

Attribute	UI Label	Description
Slots	Setup Container Contents	An ordered list of Port assignments (positions start at 1)
Flow Direction	Source Container / Destination Container	Whether this container provides or receives signals
Template	Template	Optional reference to a Port Container Template for structure enforcement

Display names: Port Containers use the Primary, Panel, Monitoring, and Mixer Name fields defined in Nodes: Naming.

Behavioral settings:

Setting	Effect
Show Parameters From Ports	Surfaces parameters from contained Ports onto the Control Panel
Disconnect Destination Ports On Replacing This Source	Disconnects destination Ports that do not match when this Source Container is replaced

Slots

A Slot is a single position within a Port Container. Each slot has a position number (starting at 1) and a format type. A slot references either:

A Flow Port on a Node (direct reference) - the standard case
A Portal (dynamic reference) - the slot resolves to whatever Port the Portal currently wraps

Slots are shown in the hi web interface under Setup Container Contents when editing a container. Operators move Ports from the available Port list into the container and arrange them.

Port Container Templates

Templates define a Port Container's structure as a set of slot definitions before any real Ports are assigned. They allow standardized container layouts (for example, "4x SDI + 2x Audio") that enforce consistent structure across the system.

Property	Purpose
Slots	List of slot definitions specifying expected positions and format types
Connect Matching Templates Only	When enabled, routing requires the matching Port Container Template

Portals

A Portal is a specialized Port Container that manages exactly one slot. It acts as a virtual, named routing point - an indirection layer that decouples operator workflows from physical infrastructure.

Portal States

A Portal is always in one of three states:

State	Description
Assigned to Port	Wraps a specific Flow Port on a Node. The Portal resolves to that Port's signal and format.
Assigned to Portal (chaining)	Linked to another Portal. Linking copies that Portal's current assignment; reassigning the referenced Portal later does not update this Portal.
Unassigned	Not connected to anything. Ready for assignment.

See Portals for Portal connections, chaining, loop detection, Portals inside Port Containers, and access and licensing requirements.

Containment Rules

What Can Be Inside What

Relationship	Allowed?	Notes
Port inside a Port Container	Yes	Standard use case the slot references a device Port directly
Port inside a Portal	Yes	A Portal's single slot wraps one Port
Portal inside a Port Container	Yes	A slot can reference a Portal for dynamic resolution
Portal inside a Portal (chaining)	Yes	One Portal's slot references another Portal
Port Container inside a Portal	No	A Portal holds exactly 1 slot; it can only point to a Port or another Portal
Port Container inside a Port Container	No	Slots reference Ports or Portals, not other containers; no recursive nesting

Containment Rules

Nesting Diagram

Node and Slot Relationships

Connection and Routing

How Routing Works

When an operator connects a Source to a Destination - whether individual Ports, Port Containers, or Portals - hi creates a routing record at the Flow Layer that tracks the connection through its lifecycle.

Connection sides:

Source: A Source Container, a Portal, or a single Port
Destination: A Destination Container, a Portal, or a single Port

Connection Lifecycle

Routing a connection moves through three phases:

Phase	Description
1. Requested Routes	All Port pairs the operator requested to connect
2. Routes That Changed	The subset that actually needed to change (already-routed pairs are excluded)
3. Confirmed Routes	Routes that the controlled device reports as applied

These phases distinguish the requested route set from the routes that changed and the routes confirmed by controlled devices.

Connection Status

In the Control Panel's Port Container status view, slot indicators use the labels Connected, Connected but shuffled, Not connected, Pending connection, or Connection not possible. A single container can show more than one slot status.

Connection Rules

Format type matching - Two Ports can only connect if their format types match exactly.
Port Container pairing - In the Connect Port Containers dialog, Source and Destination rows pair by displayed row number. Drag either set of rows to change the mapping before taking the route; the default order maps Slot 1 to Slot 1, Slot 2 to Slot 2, and so on.
Template enforcement - If Connect Matching Templates Only is enabled, routing requires matching Port Container Templates.
One connection per destination - Only one active Source connection per Destination at a time. Connecting a new Source replaces the previous one.

Updating Connections After Container Changes

When a Port Container is edited, select Save and update connections to apply its changed Port assignments to live routes that use it. The editor also has a Save action; saving the definition alone does not request this connection update.

A Portal assignment can affect routes through Port Containers that reference it. Review the affected routing after changing a Portal or its assignment.

Signal Path

The Signal Path represents the route from an originating Source through connected Nodes to Destinations. Flow Layer routing records describe requested and confirmed routes. The Signal Path Inspector displays the calculated trace at the Essence Layer. These are different views of the signal model.

How Signal Paths Are Built

Each Port is represented as an entry in the Signal Path tree. Connections between Ports create parent-child relationships. The tree represents the following connection types:

Component	Description
Cable / Link	A connection between Ports on different devices (physical cable or IP stream)
Crosspoint	An internal switching point within a device (for example, a route set on a router matrix)

Signal Path Structure

A single Source can fan out to multiple Destinations through the Signal Path tree. Each Destination is a leaf node.

Signal Path

Tally and Label Propagation

Caution

Tally calculation begins at Ports that report a Tally state. The hi system resolves the relevant rooted Signal Path and applies the Tally result to the affected Essence Ports. Labels and other Metadata follow their configured propagation and target rules. Do not assume that they follow Tally in the same direction.

Each Layer contributes different information to Tally calculation:

Physical Layer: which devices are connected.
Flow Layer: which signals are switched and where.
Essence Layer: which audio channel or video quadrant is active.

Putting It All Together

The following diagram relates the Flow Layer routing entities to Signal Paths and propagation:

Signal Routing Overview

The flow from operator action to signal delivery:

Operator routes a Source Port Container to a Destination Port Container (or connects Portals, or connects individual Ports)
hi resolves any Portal references to their current Flow Ports
In Connect Port Containers, Source and Destination rows pair by displayed row order. Drag rows to change the mapping before taking the route; format type matching still applies.
Routing Record is created with requested, changed, and confirmed route phases
Signal Path tree is updated, establishing parent-child relationships between Ports
Tally, labels, and Metadata are evaluated using their configured propagation rules and the updated Signal Path

Quick Reference: Routing Model

Use the Glossary for term definitions. This table distinguishes the routing entities from the displayed Signal Path.

Concept	What It Represents Here	Layer
Physical Port	A connector on a device (BNC SFP RJ45)	Physical
Flow Port	A routable signal on a Node can carry multiple Essences	Flow
Essence	An atomic signal item (one audio channel one video)	Essence
Port Container	A named group of Ports that routes as a single entity	Flow
Slot	A position within a Port Container holding a Port or Portal reference	Flow
Portal	A virtual routing point that wraps one Flow Port or chains to another Portal	Flow
Template	A slot layout definition for creating standardized Port Containers	Flow
Cable / Link	A connection between Ports on different devices	Flow
Crosspoint	An internal switching point within a device	Flow
Signal Path	The calculated route displayed by the Signal Path Inspector	Essence in the inspector
Tally	Operational status associated with Essence Ports and evaluated across relevant Signal Paths	Essence

Constraints

Routing occurs at the Flow Layer and follows the format, row-order, template, and Destination rules in Connection Rules.
Portals resolve to one Flow Port or another Portal. Port Containers cannot contain other Port Containers.
Device-specific routing behavior and network ports are described on the Supported Integration pages.

Layers - detailed explanation of the Physical, Flow, and Essence Layers
Port Containers - conceptual introduction to grouped routing entities
Portals - conceptual introduction to virtual Sources and Destinations
Tally and Labels - how Tally propagates through Signal Paths
Route a Source to a Destination - apply a route
Inspect a Signal Path - review the read-only Essence Layer trace
Manage Port Containers - create and manage Port Containers
Manage Portals - create and assign Portals