This is a bit off topic but I'm just curious as to why? I mean, I see the possible need for perhaps two but more?
I share my network with my neighbors and I have a 4 year old so I like to keep all of my devices separated and I do a lot of QoS and traffic shaping. I have them broken down like this:
1 subnet - Guest/Neighbors (limited to 20Mbps; DHCP only; different AP)
1 subnet - Family devices (PCs, tablets, etc...; static DHCP only; different AP)
1 subnet - VoIP (high priority QoS; static DHCP only; not accessible from WLANs)
1 subnet - Streaming (limited to 20Mbps; static DHCP only; higher priority QoS than others except VoIP)
1 subnet - High security devices (my work VMs, NAS, network monitoring devices, VPN servers, and the only devices that can manage my network; static DHCP only; not accessible from WLANs)
Basically my guests, neighbors, and family can't reach any of my important devices so any malware/viruses cannot propagate over the network. My guests, neighbors, and any streaming devices can't use up more than 20% of my bandwidth (40% if combining guests/neighbors and streaming). VoIP has priority for bandwidth and streaming devices have more priority than the rest. I also have a few routers with DD-WRT that I've turned into wireless extenders but also APs so they are probably the most vulnerable to exploit so I don't want them having access to anything important. If I wasn't living in an apartment I probably wouldn't have so many but I'm a bit paranoid when it comes to securing my network especially since other people on my network are not technical at all.
Keep in mind that these subnets are only for IPv4, I haven't bothered doing anything for IPv6 since I have that firewalled pretty good.
