vlan subnetting terminology

[dogsbod]

Hi,

I was under the impression that for example networks with an IP addresses of 192.168.10.x and 192.168.20.x with subnet mask of 255.255.255.0 are the same subnet

However in most of the docs\posts I've read, the examples refer to subnets\svi with subnet masks of 255.255.255.0,
does this mean that they are actually not seperate subnets, thus routing is not necessary. Thanks for any clarification on this.

 

[vipergg]

Incorrect , if you are using a 24 bit mask then they are separate subnets and have to be routed , if you use a 16 bit subnet mask then they are the same subnet , it is all determined on what mask you use . The mask sets where the boundary is , if it is /24 then the boundary is on the 3rd field so that makes them different subnets , if it is /16 then the boundary is on the 2nd field so thus they would be in one huge subnet the 192.168.0.0 subnet , not something you want if you are going to put a lot of people on the subnet .

 

[vipergg]

A good site for learning this is

http://www.learntosubnet.com

.

 

[dogsbod]

thanks!