Example: Determining potential root causes along a path

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You can use the RCA path tool to simulate a failure along a network path. If there is no alternative path to the target entity, then the path to any device downstream of the failure will now be broken. In the production environment, the device corresponding to the failure device becomes root cause..

This example considers the devices A, B, C, and D, connected in a row. To keep things simple, interfaces are not shown:

A ------------ B ------------- C ------------- D

Network Manager polls device D from the poller entity. In the following diagram the poller entity is shown as entity X.

X
\
 \
  \
   \
    A ------------ B ------------- C ------------- D
If a PingFail alert is injected onto device B, this alert makes node B inactive and breaks the path from A to D and causes the RCA path tool to return the following results:
  • Full path (atoz.full): this displays the shortest path between nodes A and D, regardless of the current state of the network. Consequently, atoz.full displays the path from A to D.
  • Current path (atoz.current): this displays the shortest path between nodes A and D, taking into account the current state of the network. As node B is inactive, there is no path from A to D, therefore no path returned.
In the corresponding production environment, if a PingFail alert were to occur on node D, this alert would be suppressed, and the alert on node B would be highlighted as the root cause.