traderyoda
Occasional Visitor
I’m trying to get my head around subnetting as I venture in VLAN setups home/small business network. I have an all-Ubiquiti network with a UDM-Pro gateway, Unifi 24-port switch, and UAC WiFi device – all rock solid so far. Here’s my really dumb question...
I’m trying to sort out two different approaches.
Approach A: Let’s say I start with a private Class C address like 192.168.143.0 with a 255.255.255.0 (/24) mask – that yields 254 usable addresses. Then I see folks assigning 192.168.10.0/24, 192.168.10.0/24, 192.168.10.0/24,... etc. addresses to their VLANs (VLAN10, VLAN20, VLAN30,... etc.). The subnets have a different address in the third octet.
Approach B: What’s wrong with defining 192.168.143.0/28 (255.255.255.240)? This yields 16 subnets with 14 addressable hosts per subnet with the first three octets the same. Why not assign VLAN10 to a range like 192.168.143.49 - 192.168.143.62; VLAN20 to 192.168.143.65 - 192.168.143.78, etc.
I read the article about segmenting a small LAN but still can’t catch on. I can understand why Approach A is a neat and organized framework, but you still only have 254 usable addresses, right? If is okay to go this way if you’re sure you won’t need more that 254 hosts? In Approach B, I can see inefficiency in losing addresses at the beginning and end of each subnet, but why is this an option folks don’t seem to use? Am I missing something fundamental about Layer 2 and 3 definitions?
Thanks for helping to straighten me out.
I’m trying to sort out two different approaches.
Approach A: Let’s say I start with a private Class C address like 192.168.143.0 with a 255.255.255.0 (/24) mask – that yields 254 usable addresses. Then I see folks assigning 192.168.10.0/24, 192.168.10.0/24, 192.168.10.0/24,... etc. addresses to their VLANs (VLAN10, VLAN20, VLAN30,... etc.). The subnets have a different address in the third octet.
Approach B: What’s wrong with defining 192.168.143.0/28 (255.255.255.240)? This yields 16 subnets with 14 addressable hosts per subnet with the first three octets the same. Why not assign VLAN10 to a range like 192.168.143.49 - 192.168.143.62; VLAN20 to 192.168.143.65 - 192.168.143.78, etc.
I read the article about segmenting a small LAN but still can’t catch on. I can understand why Approach A is a neat and organized framework, but you still only have 254 usable addresses, right? If is okay to go this way if you’re sure you won’t need more that 254 hosts? In Approach B, I can see inefficiency in losing addresses at the beginning and end of each subnet, but why is this an option folks don’t seem to use? Am I missing something fundamental about Layer 2 and 3 definitions?
Thanks for helping to straighten me out.
