I am in the process of understanding a bit deeper the functionality of bridges however i am a bit confused on the matter.
I still dont understand why would you pick a bridge over a router when you bridge two different subnets.
Assuming you gave:
No default gateways on either networks.
Even if you use a bridge here, the hosts inside network_a wont be able to communicate with hosts on network_b. You need a router to route the layer3. If so, then you will just use the router to connect the network without the need of the Bridge.
How/Why would you use a bridge to connect two different subnets assuming you gave no gateway?
That been said, how does software bridging works without having default gateways?