One of the fundamental elements of the security system LAN-RING is the fast data forwarding to a back-up line. Since 2008, this function has been performed by LAN-RING.v1 protocol with a switchover time of 30ms from the time of the failure. Each ring in the system has a unique ID and one switch with the MASTER function (controls the ring). The higher port of the MASTER switch is normally set to a BLOCKING mode, hence preventing a loop. A port in BLOCKING mode receives only LAN-RING frames and blocks all other data (back-up line). If a failure occurs, the state of the blocked port changes to FORWARDING and starts to transmitting all data.
During the failure creation and resolution, there are 2 short interruptions in the route. The second interruption provides the switch over from the back-up line back to the MASTER switch. Since the end of 2014, a new innovated version of LAN-RING.v2 has become available. The MASTER function (switch with the MASTER function controls the ring) always in the case of a failure, dynamically moves to the switch adjacent to the failure. From beginning of the problem until the resolution of the problem, occurs one interruption of a maximum 30ms.
The switch over time to the back-up line is for LAN-RING protocols negligibly dependent on the number of switches connected in the ring. With each switch connected to the ring, the reconfiguration time increases by only about 6μs!
The table below shows an overview of switch over time for RSTP, RSTP-M and LAN-RING.v2 protocols.