I have a pair of SG350X's connected with a trunk.
The trunk configuration is: 1T, 68T, 10T, 11T, 999U
To each of the switches is configured a network device from Hirschmann. These devices communicate with a proprietary protocol which requires tagged communication in VLAN 1. The uplink ports for these devices are configured as trunks with 1T, 68U.
The protocol is IPv4 unicast and appears to take the base MAC of the switch, lets say 00:80:63:AA:AA:64. It then adds 1 to come to make source MAC for the frame (e.g. 00:80:63:AA:AA:65), and another 1 to make the dest MAC of the frame (e.g. 00:80:63:AA:AA:66).
I can see from Wireshark (PIC) that the Hirschmann protocol is using Ethernet II frames, with a 802.1Q VLAN tag (0x8100).
The VLAN tag sets Pri:7 and ID: 1.
Within this is encapsulated SNAP-LLC, 0xAA, 0x03, with a Hirschman Org code 0x008063 and protocol ID 0x0800.
The problem I have is that I can see the frames on the uplink with wireshark using a TAP, but they don't appear to be flooded onto the trunk between switches even though the Eth II DMAC is unknown in the CAM table.
I was a little confused by 802.2 type SNAP-LLC appearing in an Ethernet II frame and not in 802.3 as one might usually expect for STP etc. I didn't realise this was a valid encapsulation.
Can anyone advise if the Cisco switch should be able to process this and forward this traffic correctly and any ideas why it isn't working?
I didn't think to do a SPAN on the Cisco side of the uplink and see if the switch actually shows the frames being received, I can try that next time I am on site.
