diff --git a/rdpy/protocol/common/error.py b/rdpy/protocol/common/error.py
index 6832c54..4b4f791 100644
--- a/rdpy/protocol/common/error.py
+++ b/rdpy/protocol/common/error.py
@@ -2,6 +2,16 @@
 @author: sylvain
 '''
 
+class InvalidValue(Exception):
+    '''
+    raise when invalid value type occured
+    '''
+    def __init__(self, message):
+        '''
+        constructor with message
+        '''
+        Exception.__init__(self, message)
+
 class InvalidExpectedDataException(Exception):
     '''
     raise when expected data on network is invalid
diff --git a/rdpy/protocol/common/stream.py b/rdpy/protocol/common/stream.py
index 340dc23..02e6196 100644
--- a/rdpy/protocol/common/stream.py
+++ b/rdpy/protocol/common/stream.py
@@ -1,14 +1,100 @@
 '''
-Created on 12 aout 2013
-
 @author: sylvain
 '''
+
 import struct
 from StringIO import StringIO
+from error import InvalidValue
+
+class Type(object):
+    '''
+    root type
+    '''
+    def write(self, s):
+        '''
+        interface definition of write function
+        '''
+        pass
+    
+    def read(self, s):
+        '''
+        interface definition of read value
+        '''
+        pass
+
+class SimpleType(Type):
+    '''
+    simple type
+    '''
+    def __init__(self, value):
+        self._value = value
+        
+class ComplexType(Type):
+    '''
+    keep ordering declaration of simple type
+    in list and transparent for other type
+    '''
+    def __init__(self):
+        '''
+        init list of simple value
+        '''
+        self._type = []
+    
+    def __setattr__(self, name, value):
+        '''
+        magic function to update type list
+        '''
+        if isinstance(value, Type):
+            self._type.append(value)
+        self.__dict__[name] = value
+        
+    def __iter__(self):
+        '''
+        iteration over object
+        '''
+        for i in self._type:
+            yield i
+            
+    def write(self, s):
+        '''
+        call format on each ordered subtype
+        '''
+        for i in self._type:
+            i.write(s)
+
+class Uint8(SimpleType):
+    '''
+    unsigned byte
+    '''
+    def __init__(self, value):
+        '''
+        constructor check value range
+        '''
+        if value < 0 or value > 0xff:
+            raise InvalidValue("invalid uint8 value")
+        SimpleType.__init__(self, value)
+    
+    def write(self, s):
+        '''
+        write value in stream s
+        '''
+        s.write(struct.pack("B", self._value))
+        
+    def read(self, s):
+        '''
+        read value from stream
+        '''
+        self._value = struct.unpack("B",self.read(1))[0]
+    
 
 class Stream(StringIO):
-    
+    '''
+    use string io inheritance
+    '''
     def dataLen(self):
+        '''
+        no read length
+        '''
         return self.len - self.pos
 
     def read_uint8(self):
@@ -38,6 +124,9 @@ class Stream(StringIO):
     def read_lesint32(self):
         return struct.unpack("<i",self.read(4))[0]
     
+    def writeType(self, t):
+        t.write(self)
+    
     def write_uint8(self, value):
         self.write(struct.pack("B", value))
     
diff --git a/rdpy/protocol/rdp/gcc.py b/rdpy/protocol/rdp/gcc.py
new file mode 100644
index 0000000..9ae8226
--- /dev/null
+++ b/rdpy/protocol/rdp/gcc.py
@@ -0,0 +1,56 @@
+'''
+@author sylvain
+@summary gcc language
+'''
+#constants declaration
+#server data
+SC_CORE =           0x0C01
+SC_SECURITY =       0x0C02
+SC_NET =            0x0C03
+
+#client data
+CS_CORE =           0xC001
+CS_SECURITY =       0xC002
+CS_NET =            0xC003
+CS_CLUSTER =        0xC004
+CS_MONITOR =        0xC005
+
+#depth color
+RNS_UD_COLOR_8BPP =         0xCA01
+RNS_UD_COLOR_16BPP_555 =    0xCA02
+RNS_UD_COLOR_16BPP_565 =    0xCA03
+RNS_UD_COLOR_24BPP =        0xCA04
+
+RNS_UD_24BPP_SUPPORT =      0x0001
+RNS_UD_16BPP_SUPPORT =      0x0002
+RNS_UD_15BPP_SUPPORT =      0x0004
+RNS_UD_32BPP_SUPPORT =      0x0008
+
+RNS_UD_SAS_DEL =            0xAA03
+
+#rdp version
+RDP_VERSION_4 =             0x00080001
+RDP_VERSION_5_PLUS =        0x00080004
+
+RNS_UD_CS_SUPPORT_ERRINFO_PDU =       0x0001
+
+class ClientCoreSettings:
+    '''
+    class that represent core setting of client
+    '''
+    rdpVersion = RDP_VERSION_5_PLUS
+    desktopWidth = 800
+    desktopHeight = 600
+    kbdLayout = 0x409
+    clientBuild = 2100
+    clientName = "rdpy"
+    keyboardType = 4
+    keyboardSubType = 0
+    keyboardFnKeys = 12
+    postBeta2ColorDepth = RNS_UD_COLOR_24BPP
+    
+class ServerCoreSettings:
+    '''
+    server side core settings structure
+    '''
+    rdpVersion = RDP_VERSION_5_PLUS
\ No newline at end of file
diff --git a/rdpy/protocol/rdp/mcs.py b/rdpy/protocol/rdp/mcs.py
new file mode 100644
index 0000000..e69de29