So, i have two cisco switches connected to my CRS305-1G-4S+IN.
If i connect only one switch, is all good, but a soon as i connect the second one, both switches put their interfaces in error-disabled because of UDLD specifically:
%UDLD-4-UDLD_NEIGHBOR_MISMATCH: UDLD neighbor mismatch detected, exp: Ethernet1/31, rec Ethernet1/32.
only way to have the connection working i must disable UDLD con the switches.
Am i missing something?
From what i can gather:
the mirkotik switch has no idea about what UDLD is, but sees it as a layer 2 multicast frame (01-00-0C-CC-CC-CC) and floods it out of all ports.
As result the cisco switches see themselves as UDLD neighbors but the wrong port ID are received and err-disable the ports..
so, two questions arise:
1 - does or will RouterOS support UDLD (https://tools.ietf.org/html/rfc5171)
2 - can i filter the mac address safely without impact on the HW performance? (this mac is used only for VTP or UDLD)
i wonder if anyone has any idea