diff --git a/.obsidian/workspace b/.obsidian/workspace
index db332ff..3a2e8c0 100644
--- a/.obsidian/workspace
+++ b/.obsidian/workspace
@@ -88,14 +88,14 @@
   "active": "bc6e8ad9aa0f44c3",
   "lastOpenFiles": [
     "School/Analyse/Layers/2. Datalink Layer.md",
+    "School/Analyse/Images/distortion.png",
+    "School/Analyse/Images/noise-signal.png",
+    "README.md",
     "School/Analyse/Layers/3. Network Layer.md",
     "School/Analyse/Layers/4. Transport Layer.md",
     "School/Analyse/Layers/1. Physical Layer.md",
     "School/Analyse/Comminucation Mediums.md",
     "School/Analyse/Images/modulation-amplitude.png",
-    "School/Analyse/Images/modulation-phase-2.png",
-    "School/Analyse/Images/modulation-phase.png",
-    "School/Analyse/Images/modulation-frequency.png",
-    "School/Analyse/Images/encoder.png"
+    "School/Analyse/Images/modulation-phase-2.png"
   ]
 }
\ No newline at end of file
diff --git a/distortion.png b/School/Analyse/Images/distortion.png
similarity index 100%
rename from distortion.png
rename to School/Analyse/Images/distortion.png
diff --git a/noise-signal.png b/School/Analyse/Images/noise-signal.png
similarity index 100%
rename from noise-signal.png
rename to School/Analyse/Images/noise-signal.png
diff --git a/type-cables.png b/School/Analyse/Images/type-cables.png
similarity index 100%
rename from type-cables.png
rename to School/Analyse/Images/type-cables.png
diff --git a/School/Analyse/Layers/2. Datalink Layer.md b/School/Analyse/Layers/2. Datalink Layer.md
index 60c411e..a0fef82 100644
--- a/School/Analyse/Layers/2. Datalink Layer.md	
+++ b/School/Analyse/Layers/2. Datalink Layer.md	
@@ -3,4 +3,21 @@ The Data Link Layer is responsible for handling the data transfer between two de
 
 The Data Link Layer also splits up packets into smaller chunks called a frame. The reverse happens on the receiving device (reassembling frames into packets).
 
-Like the Network Layer the Data Link Layer is also responsible for flow control and error checking. However it only does this for inter-network communications. (Local network)
\ No newline at end of file
+Like the Network Layer the Data Link Layer is also responsible for flow control and error checking.
+
+## Error detection
+Transmissions are not always error free. In case of an error, it should be detected and the message should be re transmitted (whenever possible)
+
+Detecting errors are handled by different algorithms:
+- Parity bits
+- CRC
+
+## Data Framing
+Data is split up in smaller chunks called frames. For each frame we add some extra data:
+
+- Who is sender?
+- Who is receiver?
+- Length of chunk
+- Type of chunk (normal message, error me)
+- Error checking values (ex. CRC code)
+- Data and metadata are put in single message called frame
\ No newline at end of file