I recently encountered a strange problem when using a CRS328-24P-4S+RM. I'm not really sure if this is even a RouterOS problem, as it also happens on SwOS, but interestingly just on the CRS328 and not when using a CRS112-8P-4S-IN. But one by one...
We are doing an installation in a theatre with a so called "light sign" system. Stage Manager has a RGB keyboard which controls RGB light signs at various positions at the stage to give commands to the actors. Imagine it as a bunch of keyboard controllable traffic lights. These are custom made devices which use Microchip MCUs with TCP/IP-stack. The light signs establish a 10MBit/s half-duplex connection to the switch and are PoE powered. Communication is done by multicast, all devices send to 239.192.0.10.
Pressing a key on the keyboard sends the following 133 byte package to all devices:
Code: Select all
0000 49 4c 43 53 79 73 44 01 59 ff 59 ff 59 ff 02 47
0010 ff 47 ff 47 ff 03 59 ff 59 ff 59 ff 04 59 ff 59
0020 ff 59 ff 05 58 00 58 00 58 00 06 58 00 58 00 58
0030 00 07 58 00 58 00 58 00 08 58 00 58 00 58 00 09
0040 58 00 58 00 58 00 0a 58 00 58 00 58 00 0b 58 00
0050 58 00 58 00 0c 58 00 58 00 58 00 0d 58 00 58 00
0060 58 00 0e 58 00 58 00 58 00 0f 58 00 58 00 58 00
0070 10 47 00 47 ff 47 ff 11 47 00 47 ff 47 ff 12 47
0080 ff 47 ff 58 00
Code: Select all
0000 49 4c 43 53 79 73 45 03 01 01 01
But now comes another curiosity. The light signs have a button that can give a command back to the stage manager. Pressing it sends the following 8 byte packet to the RGB keyboard:
Code: Select all
0000 49 4c 43 53 79 73 21 03
As already mentioned, this seems to happen only on the CRS328, even when using SwitchOS, which is quite concerning. Firmware is up to date. I fear some hardware-issue regarding 10MBit half duplex on the CRS328 and (maybe, but not necessarily) multicast...
What encourages me in this assumption is that putting a 5€ switch between the CRS and the light sign solves the problem.
Any ideas on the this? I'm pretty sure that I checked all software options that could have influence on this (IGMP, storm protection, PoE handling, ...). Having the problems even on SwitchOS where the CRS acts pretty much as a "dumb" unmanged switch leaves me clueless.