IBM xSeries 445 8870 User Manual page 57

When alerts are generated, they are forwarded to the Remote Supervisor Adapter,
ASM processor, or ASM PCI adapter on the ASM interconnect network that has the
communication resources to forward the alert. If no system on the ASM interconnect
network meets the requirements, the alert is set for transmission if the connection
type is configured or becomes available later.
If multiple modems or network connections exist in the ASM interconnect network,
you cannot specify which system will receive an alert or which will use its modem or
network connection to forward the alert. If an alert is forwarded to a Remote
Supervisor Adapter, ASM processor, or ASM PCI adapter that is unable to deliver
the alert (for example, the modem it is configured to use has failed or the network
cannot resolve the destination IP address), the processor or adapter attempts to
forward the alert to another system on the ASM interconnect network that has the
communication resources to forward the alert.
Alerts are typically sent only once (per connection type), but an alert is forwarded to
another interconnect device if the resources exist on other interconnect devices in
the network. For example, on a three ASM processor network where ASM
processor 1 generates a modem alert, but does not have a modem and the other
ASM processors have modems, the following might occur:
If ASM processor 1 generates an alert and the modem is unplugged from ASM
processor 2 45 seconds prior to ASM processor 1 generating the alert, ASM
processor 1 forwards the alert to ASM processor 2, having previously determined
that ASM processor 2 has an available modem. When ASM processor 2 receives
the forwarded alert, it determines that a modem is attached to ASM processor 3,
and forwards the alert. Therefore, depending upon the time frame (45 seconds)
within which a resource (modem) fails, the alert might be forwarded multiple times
until an interconnect device can send the alert.
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Chapter 2. Configuring the server