Is a ping sent to each child interface of a device to compute interface reachability?
eHealth sends out one set of ping packets to a given IP address, and as long as the parent device and the interfaces share the same IP address, the results of the ping test apply to each of the interfaces as well as the parent element. For the Concord poll ping, 5 pings are sent. Note this number is different for alternate latency or SAA/RTTMON pings.
Therefore, as long as the parent element and the interfaces share the same IP address, the Reachability will be the same for all of the elements. Note that the Availability may may be different, but the Reachability will be the same.
The NH_DISCOVER_IF_IP_ADDR environment variable controls how eHealth assigns ip address for interfaces.
Valid values are:
off - enables discovery and polling of interfaces by the polled IP address of the device.
on - enables discovery and polling of interfaces by the interface IP address.