diff --git a/Notes_on_protocols/Images_mobile_communication/2G_authentication_procedure.png b/Notes_on_protocols/Images_mobile_communication/2G_authentication_procedure.png
new file mode 100644
index 00000000..f1a2c5cb
Binary files /dev/null and b/Notes_on_protocols/Images_mobile_communication/2G_authentication_procedure.png differ