In this example, ENA identifies the true cause of a problem as being the failing network element (IP address) closest to the Entuity server.
ENA identifies the upstream point by first recognizing the traceroute path taken to a device, but this only includes the inbound IP addresses, e.g.:
- hop 1 - 10.44.1.1
- hop 2 - 10.45.1.2
- hop 3 - 10.46.1.1
To derive the outbound IP addresses:
- ENA identifies the IP addresses upstream of the switch, starting from 10.46.1.1.
- ENA identifies its upstream node by finding the device associated with the IP address of the preceding hop (i.e. 10.45.1.2 on router-2).
- ENA then searches through the list of all other IP addresses on that device to find the one that is in the same subnet as the downstream hop (i.e. 10.46.1.2 on router-2 is in the same subnet as 10.46.1.1 on switch-1). This IP address is then taken as the one to fill the gap between hop 2 and hop 3. A similar procedure is applied to fill the gap between hop 1 and hop 2.