Almbus/IP

almbus/ip
Developer	Netroda Technologies
Type	Alarm Signaling Protocol
Transport	UDP/IPv4, UDP/IPv6
Identifier	x-azh-almbusip
Initial Release	0.0.1 (1998)
Revision	1.2.0 (2021)
Platform	Extensible Services / Server
Extended from	Inter-Networking Electronics Protocol

ALMBUS (abbreviation of alarm bus) is a alarm signaling protocol used to publish, store and recall alarm situations on various building infrastructure devices. The suffix IP indices that this version transmits all data via a IP Networks, for example Ethernet (IEEE 802.3). ALMBUS can be used to invoke a alarm status on software devices from hardware alarms (like fire alarm system) or vice-versa.

Overview

ALMBUS devices are connected together using a ring network (almbus-lo) or, when used as IP protocol, any possible network topology. Every enabled device has the ability to raise alarms, receive alarms and forward/repeat alarms for requesting devices. Each Device can be assigned a unique device identification, alarm groups, restrictions and / or limitations.

The actions taken once upon a device received or raises a alarm are different. for example, The Digital Signage system SignMatic displays a alarm-specific information message on all displays, and refuses to accept any user request to display something else unless all alarms are cleared.

Technical

Devices that are ALMBUS-Enabled (usually part of the ES-Platform) are enabled to issue alarms. the IP version uses UDP Muticast groups to publish and receive alarms, the system can be configured to use perfect forward secrecy to minimize alarm hijacking, however it is strongly discouraged to use ALMBUS on publically accessible networks.

To prevent false alarms, ALMBUS/IP incorporates several mechanisms to ignore malformed, unsolicited messages from other protocols or services, that may wrongly use the assigned broadcast address and port in the same network.

ALMBUS supports

• Message payload encryption
• Alarm groups
• Alarm identities
• Specific/Custom alarms
• Global perfect forward secrecy
• Single device muting

By default, all Extensible Services / Server compatible products include ALMBUS. The ALMBUS reference implementation is currently present in 40+ Programming languages free to use and implement.

In theory, every ALMBUS enabled device that runs compatible implementation automatically joins the alarm group of the current broadcast domain. To connect indepenedent broadcast domains (for example different VLANS or router subnets) to the same ALMBUS group, the firewalls must be configured to pass UDP Multicast traffic in the assigned ranges or use a ALMBUS gateway solution.

Message Types

Alarm Type	Description
Danger	Indicates a dangerous situation occuring in the current context, for example mass shootings, terrorism attacks etc.
Fire	Requests immediate evacuation of the assigned area, as the building or structure is on fire
Evacuate	Requests immediate evacuation of the assigned areas
Havary	Raised when building infrastructure has severe malfunctions, like leaking pipes causing flooding or overheating of a structure due to failure on climatic systems
Catastrophy	Used for scenarios where a natual catastrophy is awaited or happening, for example tsunamis, hurricanes or thunderstorms
Clear	Indicates that a alarm has been revoked.
Information	Generous, non-dangerous announcements

License

Considering the importance of life safety, The ALMBUS specification is royalty-free and associated documentation is available to the public.

See also

• Extensible Services Server