Atop Technology EH7510 User manual - Manual (Page 74)

Atop Industrial Managed Ethernet Switch
EH7510
User Manual V 1.0
68
Fig. 2.56
As Fig. 2.56 shows, each Ethernet Ring Node is connected to adjacent Ethernet Ring
Nodes participating in the same Ethernet Ring using two independent links (i.e. two ways).
In the Ethernet ring, loops can be avoided by guaranteeing that traffic may flow on all but
one of the ring links at any time. This particular link is called Ring Protection Link (RPL). A
control message called R-APS coordinates the activities of switching on/off the RPL. Under
normal conditions, this link is blocked by the Owner Node. Thus loops can be avoided by
this mechanism. In case an Ethernet ring failure occurs, the RPL Owner node will be
responsible to unblock its end of the RPL to allow RPL to be used for traffic. The RPL is as
the backup link when one link failure occurs.
Fig. 2.57
RPL