What the Notification Forwarder Object Is
The Notification Forwarder object, defined in Clause 12.51 of ANSI/ASHRAE 135-2024, receives event notifications and re-distributes them to its own list of recipients. Unlike a Notification Class, which originates notifications for a BACnet device’s own alarming objects, the Notification Forwarder does not originate anything; it relays notifications that other devices produce, acting as a routing hub for event traffic.
Recipient_List names the destinations the object forwards to, Subscribed_Recipients holds recipients that subscribed dynamically, and Process_Identifier_Filter and the optional Port_Filter narrow which notifications are relayed. Local_Forwarding_Only controls whether forwarding stays on the local network. The Notification Forwarder applies no event algorithm; forwarding depends on the device also being able to receive the event notifications it relays.
Where You’ll See It
- Alarm aggregation. A supervisory device runs a Notification Forwarder that gathers notifications from many field controllers and relays them to a smaller set of workstations.
- Recipient fan-out. A single incoming notification re-distributed to several destinations, so adding a recipient is one edit on the forwarder rather than a change on every source.
- Filtered relay.
Process_Identifier_FilterandPort_Filterpass only the notifications that matter to a given downstream system.
Required Properties
Clause 12.51 requires every Notification Forwarder object to provide these properties. Datatypes are the spec’s names: BOOLEAN is a true/false flag, BACnetLIST of BACnetDestination the recipient list, and the other BACnet-prefixed types are structured values defined by the standard. Subscribed_Recipients is writable.
| Property | Datatype | What it holds |
|---|---|---|
Object_Identifier | BACnetObjectIdentifier | The object’s type and instance number, unique within the device |
Object_Name | CharacterString | The human-readable point name, unique within the device |
Object_Type | BACnetObjectType | Always notification-forwarder for this object |
Status_Flags | BACnetStatusFlags | Four health flags: in-alarm, fault, overridden, out-of-service |
Reliability | BACnetReliability | Whether the object detects a fault, and if so which |
Out_Of_Service | BOOLEAN | When true, forwarding is decoupled for testing |
Recipient_List | BACnetLIST of BACnetDestination | The configured destinations, each qualified by day and time window |
Subscribed_Recipients | BACnetLIST of BACnetEventNotificationSubscription | Writable; recipients that subscribed dynamically |
Process_Identifier_Filter | BACnetProcessIdSelection | Which process identifiers of incoming notifications are forwarded |
Local_Forwarding_Only | BOOLEAN | When true, forwarding is limited to the local network |
Property_List | BACnetARRAY[N] of BACnetPropertyIdentifier | The list of properties this instance actually implements |
Optional Properties
The property integrators meet most is Port_Filter, which restricts forwarding to selected network ports. Description labels the object.
| Property | Datatype | Group |
|---|---|---|
Description | CharacterString | General |
Port_Filter | BACnetARRAY[N] of BACnetPortPermission | Integration |
Reliability_Evaluation_Inhibit | BOOLEAN | Fault detection |
Audit_Level | BACnetAuditLevel | Auditing |
Auditable_Operations | BACnetAuditOperationFlags | Auditing |
Tags | BACnetARRAY[N] of BACnetNameValue | Tagging and profile |
Profile_Location | CharacterString | Tagging and profile |
Profile_Name | CharacterString | Tagging and profile |
Related Objects
- Notification Class: originates notifications for local alarming objects, where the forwarder relays notifications from elsewhere.
- Alert Enrollment: originates alerts as an event source, another event-producing object.
- Audit Reporter: distributes audit notifications, a related distribution role for the audit trail.
What Chipkin Provides
The Notification Forwarder object is modeled in the CAS BACnet Stack and served as a configurable object with its recipient and filter properties; active forwarding requires event-notification receive, which is a roadmap item. Talk to us about modeling your device’s points.