The article says: "....convert a daisy chain of applications into a ring, provided that the controller has two interfaces that support redundant operation." Is this redundancy also guaranteed if a single-interface Managing Node is connected to the ring via a Powerlink compatible hub?
Best regards!
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
For ring redundancy you need a hub with ring-master functionality (i.e. a hub that can open or close the ring depending on the state). If you've got such a hub, the ring segment will be redundant. This is of course independent from the type of nodes (MN or CNs) connected to the ring.
Best regards,
Wolfgang
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Sorry for digging this old topic. I'm interested by ring topology with POWERLINK.
In EPSG DS 302-A V1.1.0, §4.1 I read :
"In case of medium failure the ring is “opened”. At this time the MN will not receive frames on the second port, that have been sent by itself. Then the MN will transmit and receive on both ports. PRes frames will have to be propagated to the other port to allow CN to CN communication, i.e. the two ports act as a standard hub."
I understand that, if I have one interface on the MN, I must used hub with ring-master capability. But if I have 2 interfaces on the MN, does OpenPOWERLINK allow message propagation on the second interface (as said in EPSG DS 302-A V1.1.0) ? In this case, propagation take long time, if propagation is done by POWERLINK software ? Must I implement hardware (FPGA or ASIC) for message propagation ?
Last question : if I use master redundancy on a ring network, if AMN breaks dowmn, how long is switchover is this case (first RMN must become AMN, then must detect that ring is opened and propagate message on the second interface) ?
Best regards
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
May be you have already figured it out but just in case, pfb some information which can be of help.
If you are using a two-port openPowerlink master, currently the stack package (which includes openMAC and openHUB) does not have the Ring redundancy implemented. You would need to handle it in your FPGA or ASIC. Currently you cannot form a ring in the network with the 2-master ports, as the frames will collide creating network errors.
To answer your second question, the master switching has to happen within a Powerlink cycle when a loss of SoC is detected. For a ring break, the master shall switch the two-port-hub mode of operation from rx/tx-rx/monitoring to rx/tx-rx/tx as frame loss is detected on the monitored port. In the use-case you've mentioned, it will depend on the actual scenario i.e. whether the physical layer on the primary master is still functional or if the standby master has already switched its mode of ring before switching to master status.
Hi,
I am new to POWERLINK and my understanding is that the CN has nothing to do with the ring redundancy. If the link is broken, master will take care of it. Please confirm whether my understanding is correct or not.
Best regards,
Mohammed Shibin
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello,
I have a question regarding the Ring Redundancy described in this EPSG article:
http://www.ethernet-powerlink.org/en/powerlink/technology/technology-in-deep/redundancy/
The article says: "....convert a daisy chain of applications into a ring, provided that the controller has two interfaces that support redundant operation." Is this redundancy also guaranteed if a single-interface Managing Node is connected to the ring via a Powerlink compatible hub?
Best regards!
(I'm aware that this concept would only cover line failures between CNs in the ring, and not from the MN to the ring)
Hi Ziggisto,
For ring redundancy you need a hub with ring-master functionality (i.e. a hub that can open or close the ring depending on the state). If you've got such a hub, the ring segment will be redundant. This is of course independent from the type of nodes (MN or CNs) connected to the ring.
Best regards,
Wolfgang
Hi Wolfgang,
thanks for your answer!
Hi,
Sorry for digging this old topic. I'm interested by ring topology with POWERLINK.
In EPSG DS 302-A V1.1.0, §4.1 I read :
"In case of medium failure the ring is “opened”. At this time the MN will not receive frames on the second port, that have been sent by itself. Then the MN will transmit and receive on both ports. PRes frames will have to be propagated to the other port to allow CN to CN communication, i.e. the two ports act as a standard hub."
I understand that, if I have one interface on the MN, I must used hub with ring-master capability. But if I have 2 interfaces on the MN, does OpenPOWERLINK allow message propagation on the second interface (as said in EPSG DS 302-A V1.1.0) ? In this case, propagation take long time, if propagation is done by POWERLINK software ? Must I implement hardware (FPGA or ASIC) for message propagation ?
Last question : if I use master redundancy on a ring network, if AMN breaks dowmn, how long is switchover is this case (first RMN must become AMN, then must detect that ring is opened and propagate message on the second interface) ?
Best regards
Hi Jerome,
May be you have already figured it out but just in case, pfb some information which can be of help.
If you are using a two-port openPowerlink master, currently the stack package (which includes openMAC and openHUB) does not have the Ring redundancy implemented. You would need to handle it in your FPGA or ASIC. Currently you cannot form a ring in the network with the 2-master ports, as the frames will collide creating network errors.
To answer your second question, the master switching has to happen within a Powerlink cycle when a loss of SoC is detected. For a ring break, the master shall switch the two-port-hub mode of operation from rx/tx-rx/monitoring to rx/tx-rx/tx as frame loss is detected on the monitored port. In the use-case you've mentioned, it will depend on the actual scenario i.e. whether the physical layer on the primary master is still functional or if the standby master has already switched its mode of ring before switching to master status.
Best Regards,
#aeicoriiotteam
Hi,
I am new to POWERLINK and my understanding is that the CN has nothing to do with the ring redundancy. If the link is broken, master will take care of it. Please confirm whether my understanding is correct or not.
Best regards,
Mohammed Shibin