What I've got:
Two 24 port switches in building A, with 2 fibre trunks from building A to building B – where there are two 48 port switches.
The two 24 port switches support RSTP and STP. HP 1810-24G v2.
The two 48 port switches do not. HP 1810-48G v1.
What I want to do:
I want to add a trunk between 24 Port No 1 and 24 Port No 2 (using OM3-3) so that if OM3-1 or OM3-2 become disconnected or damaged, the packets will take the alternate path to the 48 port switches in building B.
Current issue:
When I add OM3-3, the switches lock up because I'm clearly creating a loop.
My Thoughts/Queries:
All switches are currently being managed on the same VLAN, which is 1080.
Will that solve my issue if I set the management VLAN on the two 24 port switches to say VLAN 2021, and leave the 48 ports on 1080 – then tag VLAN 2021 on the trunk between 48 Port No 1 and 48 Port No 2 so the switches can see each other?
I've had no experience with RSTP so I'm at a bit of a loss. The obvious solution is to replace the two 48 port switches with models which support RSTP and be done with it.
Is there any way to achieve this without replacing the 48 port switches?
Best Answer
RSTP is completely interoperable with STP. as per standards RSTP enabled port will go STP when connected to an STP enabled network.
I assume the older 1810 switches support STP and the 1810-v2 switches support RSTP, So in your setup the loop prevention should work fine.
Do config check on all switches to ensure they have the STP or RSTP enabled at switch level (global) as well as at port level.