Definition of downstream and upstream within RCA

Use this information to understand how the terms downstream and upstream are applied within the RCA plug-in.

Definition of terms

The terms downstream and upstream are used with reference to the poller entity.

Downstream
Specifies a location on the network topologically more distant from the polling station but on the same physical path as a second location.
Upstream
Specifies a location on the network topologically closer to the polling station but on the same physical path as a second location.

In complex networks, the distance of devices from the polling station changes as devices are deactivated. This change in distance has an impact on which devices are upstream or downstream.

Example

The figure below shows an example of upstream and downstream locations. In this example, device B is downstream of device A; therefore, device A is upstream of device B.

Figure 1. Downstream and upstream devices 
Concept diagram that shows an example of downstream and upstream devices as used in root cause analysis (RCA).