diff --git a/dist/index.html b/dist/index.html
index 3a703af..b1d1bb3 100644
--- a/dist/index.html
+++ b/dist/index.html
@@ -40,7 +40,7 @@
         </div>
         <div class="col-lg-2 col-md-3 col-4">
             <div><label for="netsize" class="form-label mb-0 ms-1">Network Size</label></div>
-            <div><input id="netsize" type="text" class="form-control w-10" value="16" aria-label="Network Size" pattern="^(\d|[12]\d|3[0-2])$" required></div>
+            <div><input id="netsize" type="text" class="form-control w-10" value="16" aria-label="Network Size" pattern="^(\d|[12]\d|30)$" required></div>
         </div>
         <div class="col-lg-2 col-md-3 col-3">
             <div style="height:1.5rem"></div>
diff --git a/dist/main.js b/dist/main.js
index 1a2dc71..f6597c1 100644
--- a/dist/main.js
+++ b/dist/main.js
@@ -1,6 +1,20 @@
 let subnetMap = {};
 let maxNetSize = 0;
 let infoColumnCount = 5
+// NORMAL mode:
+//   - Smallest subnet: /30
+//   - Two reserved addresses per subnet:
+//     - Network Address (network + 0)
+//     - Broadcast Address (last network address)
+// AWS mode (future):
+//   - Smallest subnet: /28
+//   - Two reserved addresses per subnet:
+//     - Network Address (network + 0)
+//     - AWS Reserved - VPC Router
+//     - AWS Reserved - VPC DNS
+//     - AWS Reserved - Future Use
+//     - Broadcast Address (last network address)
+let operatingMode = 'NORMAL'
 
 $('input#network,input#netsize').on('input', function() {
     $('#input_form')[0].classList.add('was-validated');
@@ -221,9 +235,16 @@ function mutate_subnet_map(verb, network, subnetTree) {
         if (mapKey === network) {
             if (verb === 'split') {
                 let netSplit = mapKey.split('/')
-                let new_networks = split_network(netSplit[0], parseInt(netSplit[1]))
-                subnetTree[mapKey][new_networks[0]] = {}
-                subnetTree[mapKey][new_networks[1]] = {}
+                // operatingMode NORMAL
+                let minSubnetSize = 30
+                if (operatingMode === 'AWS') {
+                    minSubnetSize = 28
+                }
+                if (parseInt(netSplit[1]) < minSubnetSize) {
+                    let new_networks = split_network(netSplit[0], parseInt(netSplit[1]))
+                    subnetTree[mapKey][new_networks[0]] = {}
+                    subnetTree[mapKey][new_networks[1]] = {}
+                }
             } else if (verb === 'join') {
                 subnetTree[mapKey] = {}
             } else {