diff --git a/include/gsup_protocol.hrl b/include/gsup_protocol.hrl
index 5db534e..86c2785 100644
--- a/include/gsup_protocol.hrl
+++ b/include/gsup_protocol.hrl
@@ -55,7 +55,10 @@
                   | e_forward_access_signalling_req
                   | e_close
                   | e_abort
-                  | e_routing_err.
+                  | e_routing_err
+                  | epdg_tunnel_request
+                  | epdg_tunnel_error
+                  | epdg_tunnel_result.
 
 -type 'GSUPRatType'() :: rat_unknown | rat_geran_a | rat_utran_iu | rat_eutran_sgs.
 
@@ -219,7 +222,10 @@
   16#44 => #{message_type => e_forward_access_signalling_req, mandatory => [message_class, source_name, destination_name, an_apdu, session_id, session_state]},
   16#47 => #{message_type => e_close, mandatory => [message_class, source_name, destination_name, session_id, session_state]},
   16#4b => #{message_type => e_abort, mandatory => [message_class, session_id, session_state, bssap_cause]},
-  16#4e => #{message_type => e_routing_err, mandatory => [message_class, source_name, destination_name], optional => [session_id, session_state]}
+  16#4e => #{message_type => e_routing_err, mandatory => [message_class, source_name, destination_name], optional => [session_id, session_state]},
+  16#50 => #{message_type => epdg_tunnel_request, mandatory => [message_class], optional => []},
+  16#51 => #{message_type => epdg_tunnel_error, mandatory => [message_class, cause], optional => []},
+  16#52 => #{message_type => epdg_tunnel_result, mandatory => [message_class], optional => []}
 }).
 
 -define(AUTH_TUPLE_MANDATORY, [rand, sres, kc]).