I have a cisco SF 300 switch which is connected to a chinese brand BDCOM switch (2500 series full gigabit port) . When both the ports of switch are configured in access mode, it works. But when they are configured in trunk mode tagging two vlans , it doesn't work. I need to pass two vlans in between these two switches. What might be the issue ? Here is the configuration of cisco switch:
switchport trunk allowed vlan add 17,2029
BDCom switch configuration:
interface GigaEthernet0/51 switchport trunk vlan-allowed 17,2029 switchport mode trunk
Adding more: there is only single link in between two switches. If there was multiple physical link between them, we could suspect about STP issue. But it was not the case.