Tsw212 blocks profinet dcp identify request (multicast)

NETWORKING SOLUTIONS
1

Hi,

I’ve a bunch of tsw212’s used in industrial sites with Siemens S7 plc & remote IO on profinet. To my horror I just discovered that the TSW212 blocks a profinet dcp identify request! So no profinet devices found on the network when TSW212 is used.

I’ve seen some other questions about this but no answers. I know a few other switches which (wrongly) blocks profinet traffic. TP-link sg108 blocks when vlan are enabled, zyxel. Yes, it’s a pain, profinet does some strange things but such is (protocol) life. But this switch is advertised as profinet switch, you don’t expect this behaviour!

Teltonika can you help me solve this problem, how to proceed? I will also contact my supplier for this. I did like this switch but not now.

Here is a wireshark dump of the dcp request frame, mark the mutlicast mac dest addr 01:0e:cf:00:00:00:

Frame 278: 60 bytes on wire (480 bits), 60 bytes captured (480 bits) on interface eth1, id 0
Ethernet II, Src: PCSSystemtec_90:db:27 (08:00:27:90:db:27), Dst: PROFIBUSNutz_00:00:00 (01:0e:cf:00:00:00)
    Destination: PROFIBUSNutz_00:00:00 (01:0e:cf:00:00:00)
    Source: PCSSystemtec_90:db:27 (08:00:27:90:db:27)
    Type: PROFINET (0x8892)
    [Stream index: 24]
PROFINET acyclic Real-Time, ID:0xfefe, Len:  44
    FrameID: 0xfefe (Real-Time: DCP (Dynamic Configuration Protocol) identify multicast request)
PROFINET DCP, Ident Req, Xid:0x3010064, All
    ServiceID: Identify (5)
    ServiceType: Request (0)
    Xid: 0x03010064
    ResponseDelay: 128
    DCPDataLength: 4
    Block: All/All
        Option: All Selector (255)
        Suboption: ALL Selector (255)
        DCPBlockLength: 0

On a working switch you get a reply from all available profinet nodes but the request is never received. The response are not blocked because not mutlicasted

Let me know if you need more detail. see profinet-dcp

Stupid I discover this now, I was fully convinced this did work. Is it worth a try to downgrade firmware?

Let me add: I’ve tried most combinations of igmp snooping, mc querier, mrp, lldp & profinet on/off without any result. Next would be to dive into to linux networking stuff and see if I can find the right knobs hoping it is not a hardware bug of this network chip

3

Hello,

Thank you for bringing this to our attention. The Profinet DCP multicast forwarding issue is a known issue, and our R&D is already aware of it. A fix for this is expected with the release of TSWOS 1.5 firmware soon. However, I don’t have a precise release date for FW 1.5 at the moment.

If you have any additional questions or need further assistance in the meantime, please feel free to reach out.

Best regards,

4

Ah thx. Can you share a temporary workaround or have any pointers in that direction ?
Is downgrading an option?

5

Hello @michiel,

No, downgrading won’t be helpful in this case. If there’s an urgent need for a temporary solution, we’ll need to contact you privately. However, the 1.5 FW release, which will solve the initial issue, is expected pretty soon.

Let me know which approach would be most suitable for you.

Best regards,

6

For now, with some efffort I can work around so I’ll wait.
With hind sight it explains the problems we had assign new io stations. Before I buy more switches I need to be sure it works so do not wait too long.

Thx