IEC 62439-6:2010 pdf – lndustrial communication networks -High availability automation networks-Part 6: Distributed Redundancy Protocol(DRP).
ii) otherwise, the switch node shall assign an unused DRPSequencelD to the new switch node. Check if the new assigned DRPsequencelD is larger than current DRPDeviceNumber,
• if the DRPsequencelD assigned is larger than current DRPDeviceNumber, the switch node shall increment the DRPDeviceNumber by 1. and send the RingChange frame as a multicast out of the two active ring ports,
• otherwise, send the RingChange frame as a multicast out of the two active ring ports,
f) After the RlngChange frame is received, the switch node shall check If this frame was sent by the node Itself, that is:
1) if the RingChange frame was sent by the node Itself, the switch node shall stop forwarding the RingChange frame;
2) otherwise, the switch node shall set the local DRPDeviceNumber to the value of DRPDeviceNumber in the received frame. And check if the local DRPSequencelo is OxCO and the local MAC address is equal to the RingChange frame.
i) if the local switch is the one to be configured, set the local DRpSequencelD to the
values in the received frame,
Ii) otherwise, It shall take no further actions.
g) lithe following condition is met:
MOD (Local current time, Cycle) == Link Check SendTimeOffset (3)
Then it is time tnkChe to send the LinkCheck frame as a multicast out of the two active ring ports.
The switch which sent the LinkCheck frame shall do the following within the time Link Check Time Limit from the LinkCheck sending time tLinkCh.ck’
1) if the switch node has received the LinkCheck frames from both its active ring ports, it shall take no further actions;
2) if the switch node has not received the LinkCheck frame from one ring port (for example RingiPorti), it means that either the inter.switch link Is faulty or the neighbour switch connected on this ring port Is faulty, then
I) if the switch node is operating in a single ring network, it shall clear its FDB. and set this ring port (RIngiPorti) to the Blocking state. II another ring port (RinglPort2) of this switch node operates in the Blocking state, It shall switch the states of both active ring ports immediately:
ii) if the switch node is operating in a double ring network, it shall clear its FDB and then check the corresponding standby ring port (for example Ring2Portl),
• if its corresponding standby ring port (Ring2Poctl) link is up. the switch shall set this standby ring port (Ring2Portl) state from the Disabled to the original state of the broken active ring port (RingiPorti), and put the broken active ring port (Ring iPorti) into the Disabled state:
• if its corresponding standby ring port (Ring2Portl) link is down, the switch shall set the broken ring port (RingiPorti) to the Blocking. Then it shall send the LinkAlarm frame as a multicast out of the two active ring ports.
3) if the switch node has not received LinkCheck frames from either of the ring ports, it means that the switch is not connected to the ring anymore,
I) If the switch node is operating In a single ring network, It shall clear its own FOB. and set both Its ring ports (RingiPorti) to the Blocking state:
ii) if the switch node is operating in a double ring network, it shall clear its FDB and then check the corresponding standby ring port (for example Ring2Portl).
• if its corresponding standby ring port (Ring2Portl) link is up. the switch shall set this standby ring port (Ring2Portl) state from the Disabled to the original state of the broken active ring port (Ring1Port1)， and put the
broken active ring port (Ring1Port1) into the Disabled state;
●if its corresponding standby ring port (Ring2Port1) link is down, the switch shall set the broken ring port (Ring1Port1) to the Blocking. Then it shall send the LinkAlarm frame as a multicast out of the two active ring ports.