CAIRNS (Cooperative Alert Information and Resource Notification System) is a demonstrator of technologies that can be used to construct a resilient, fault-tolerant CIMS architecture. One of the main goals of CAIRNS is to demonstrate an interoperable architecture for incident notification.
On the most basic level, CAIRNS is a collection of independent nodes that can join and drop out of the network at will. Messages between nodes are passed using peer-to-peer (P2P) technologies similar to those used in file sharing networks. There is no central node, which means there is no single point of failure that would bring the whole system down. Each node caches the messages it receives and is able to forward them even if the original sender can no longer be reached. A message is purged from the cache when an update arrives or its expiration time is reached.
Interoperability with other systems is achieved by using a standards-based message format. CAIRNS message traffic is based on SOAP, a standard protocol for exchanging XML-based messages over networks. Each node acts both as a SOAP server and a SOAP client. Routing information is attached to the message using EDXL-DE (Emergency Data Exchange Language - Distribution Element).The payload of the message can be in any of the emerging XML incident report formats, such as TWML (Tsunami Warning Markup Language), CAP (Common Alerting Protocol) or EDXL-RM (EDXL - Resource Messaging). Existing systems can be connected to CAIRNS by using gateways that translate the data from existing systems into structured CAIRNS messages and vice versa.
The images below show the screen shot of CAIRNS Demonstrator running across two emergency operations centres and exchanging CAP messages of an incident involving a "person of interest" alert and an "explosion" event at a railway station.
The images below show the Cyclone Warning Markup Language (CWML) bulletins mapped on a Google-Maps interface showing the path of a cyclone, its destructive winds, and other relevant information base on the transmitted CWML messages.
