Communication of event messages in computing systems

A computer program product, comprising one or more computer readable hardware storage devices having computer readable program code stored therein, said program code executable by one or more processors to implement a method, said method comprising:

• sending, by a first computer device to a second computer device via a broadcast or multicast communication, an event notification of a notifiable management event, wherein the first computer device may connect to a management network via only a first network switch, wherein the first computer device is unable to notify a management device of the notifiable management event via the management network because the first computer device is unable to connect to the management network via the first network switch, wherein the first computer device and the second computer device are physically separated by an aisle;
• receiving, by the first computer device from the second computer device via a first unicast communication, an acknowledgment of the event notification, wherein the second computer device is able to connect to the management network via the second network switch,
• wherein the broadcast or multicast communication and the first unicast communication each use a shirt-range wireless communications technology comprising visible light communication or data-over-audio communication.