How to deal with more than 256 devices on the same subnet

[stathis]

Hello,

My company is a factory which using many tools with IP and computers to manage those tools. Right now, the overall number of ip devices approaching a full Class C subnet. And the need to separate them in two subnets became urgent.

I know that ideally had to use VLANs but this will complicate the IP address management, as there is no physical separation.

I am thinking two possible approaches and i want some advise about how to deal with it.

i) to assign two separate subnets on the same physical interface. (Is it possible?)
ii) to make the subnet /16 instead of /24. (Is there any consequence?)

I would appreciate any help.

Thanks in advance

Stathis Alexopoulos

[maximed]

@stathis I'm not an expert ( so if you can try on a small architecture it would be better )

1. You can make two different network on the same interface technically, but I don't really know how you can manage it (make a virtual interface with different parameters maybe).
   this imply if two of your devices plugged in the same switch, with different IPs, they won't communicate...

2. I suggest you to extend the subnet. You can make the mask /23 (/16 will give you up to 65534 hosts : I'm not sure you need that much ...)
   you'll get 510 hosts with a mask at /23, is it enough ?
   To get it done, you need to update the mask on every host, I suggest you to a use DHCP server.

Finally, you can handle VLANs but do you need to separate the networks ?
VLAN is great if : you have multiple networks but a few host need to talk to other networks (like 1 network by floor but only one printer in the building). Otherwise they are another annoying task to handle (rules and stuff like this)

Good luck with your problem !
Max.D

EDIT (02.12 11:05 GTM+1) : corrected error noticed by Rico

[Rico]

@maximedefrances said in How to deal with more than 256 devices on the same subnet:

you'll get 5012 hosts with a mask at /23, is it enough ?

/23 is 510 Hosts.

-Rico

[maximed]

@rico Ho yes sorry, I wrote a too fast

[stathis]

Thanks a lot, for your help.

I will try it with /23