diff --git a/.obsidian/workspace b/.obsidian/workspace
index 352ec81..cde62c4 100644
--- a/.obsidian/workspace
+++ b/.obsidian/workspace
@@ -10,7 +10,7 @@
           "type": "markdown",
           "state": {
             "file": "School/Analyse/Layers/3. Network Layer.md",
-            "mode": "source"
+            "mode": "preview"
           }
         }
       }
diff --git a/School/Analyse/Layers/3. Network Layer.md b/School/Analyse/Layers/3. Network Layer.md
index 3502617..e66a748 100644
--- a/School/Analyse/Layers/3. Network Layer.md	
+++ b/School/Analyse/Layers/3. Network Layer.md	
@@ -41,4 +41,12 @@ When a router receives a packet:
 Router needs to know how many digits are used as network ID.
 Routers keep this information in their routing table.
 
-A binary number named a netmask 
+A binary number named a netmask is used to show the network ID where 1's show the network ID.
+
+#### Example: 
+Network ID is marked as bold.
+- Netmask:
+			**11111111.11111111**.00000000.00000000
+- Address:
+			**195.210**.23.14
+