How to create 2 networks CRS328-24P-4S+

Hi brains trust,

I’ve looked all around to how I can do this

I have a CRS328-24P-4S+ which is currently in switch mode and is connected to a modem/router.

What I want to do is run 2 networks where I allocated a bank of ports to 1 network and another 2 another network, while still sharing the same internet connection.

Each network will have a different IP range.

I’d like to be put the my current modem into bridge mode and use the CRS as a router along with using the switch ports as well.

Can someone help point me in the right direction

Thank you

Do you need independent LANs, or would it suffice to have a netmask like /21 :

$ ipcalc 192.168.0.0/21
Address: 192.168.0.0 11000000.10101000.00000 000.00000000
Netmask: 255.255.248.0 = 21 11111111.11111111.11111 000.00000000
Wildcard: 0.0.7.255 00000000.00000000.00000 111.11111111
=>
Network: 192.168.0.0/21 11000000.10101000.00000 000.00000000
HostMin: 192.168.0.1 11000000.10101000.00000 000.00000001
HostMax: 192.168.7.254 11000000.10101000.00000 111.11111110
Broadcast: 192.168.7.255 11000000.10101000.00000 111.11111111
Hosts/Net: 2046 Class C, Private Internet

>

Ie. therein you could realize 8 subnets from .0.x to .7.x (/24).

I think you should use such a solution b/c the CRS3xx has a limitation that it can Hardware Offload only 1 bridge.
So you better research also these important aspects.

I would keep the current WAN router as is, and just set a static route to that /21 network (depends on what the IP and netmask of the WAN router is).

See also:
https://wiki.mikrotik.com/wiki/Manual:CRS3xx_series_switches#Port_switching
https://wiki.mikrotik.com/wiki/Manual:Interface/Bridge#Bridge_Hardware_Offloading