diff --git a/src/cloud/occi/etc/occi-server.conf b/src/cloud/occi/etc/occi-server.conf
index 6304fa24f5..859329f2df 100644
--- a/src/cloud/occi/etc/occi-server.conf
+++ b/src/cloud/occi/etc/occi-server.conf
@@ -39,11 +39,15 @@
 
 # VM types allowed and its template file (inside templates directory)
 :instance_types:
-  :custom:
-    :template: custom.erb
   :small:
     :template: small.erb
+    :cpu: 1
+    :memory: 1024
   :medium:
     :template: medium.erb
+    :cpu: 4
+    :memory: 4096
   :large:
     :template: large.erb
+    :cpu: 8
+    :memory: 8192
diff --git a/src/cloud/occi/etc/templates/common.erb b/src/cloud/occi/etc/templates/common.erb
index 459ea02e69..4dd2fbae33 100644
--- a/src/cloud/occi/etc/templates/common.erb
+++ b/src/cloud/occi/etc/templates/common.erb
@@ -41,4 +41,4 @@
 	]
 <% end %>
 
-INSTANCE_TYPE = <%= @vm_info['INSTANCE_TYPE']%>
\ No newline at end of file
+INSTANCE_TYPE = <%= @itype %>
\ No newline at end of file
diff --git a/src/cloud/occi/lib/OCCIServer.rb b/src/cloud/occi/lib/OCCIServer.rb
index 954248d3db..613ecd5333 100755
--- a/src/cloud/occi/lib/OCCIServer.rb
+++ b/src/cloud/occi/lib/OCCIServer.rb
@@ -37,6 +37,9 @@ require 'pp'
 # The OCCI Server provides an OCCI implementation based on the
 # OpenNebula Engine
 ##############################################################################
+
+COLLECTIONS = ["compute", "instance_type", "network", "storage"]
+
 class OCCIServer < CloudServer
     # Server initializer
     # config_file:: _String_ path of the config file
@@ -69,6 +72,38 @@ class OCCIServer < CloudServer
     ############################################################################
     ############################################################################
 
+    def get_collections(request)
+        xml_resp = "<COLLECTIONS>\n"
+
+        COLLECTIONS.each { |c|
+            xml_resp << "\t<#{c.upcase}_COLLECTION href=\"#{@base_url}/#{c}\">\n"
+        }
+
+        xml_resp << "</COLLECTIONS>"
+
+        return xml_resp, 200
+    end
+
+    def get_instance_types(request)
+        xml_resp = "<INSTANCE_TYPE_COLLECTION>\n"
+
+        @config[:instance_types].each { |k, v|
+            xml_resp << "\t<INSTANCE_TYPE href=\"#{@base_url}/instance_type/#{k.to_s}\">\n"
+            xml_resp << "\t\t<NAME>#{k.to_s}</NAME>\n"
+            v.each { |elem, value|
+                next if elem==:template
+                str = elem.to_s.upcase
+                xml_resp << "\t\t<#{str}>#{value}</#{str}>\n"
+            }
+            xml_resp << "\t</INSTANCE_TYPE>\n"
+        }
+
+        xml_resp << "</INSTANCE_TYPE_COLLECTION>"
+
+        return xml_resp, 200
+    end
+
+
     # Gets the pool representation of COMPUTES
     # request:: _Hash_ hash containing the data of the request
     # [return] _String_,_Integer_ Pool Representation or error, status code
@@ -504,38 +539,4 @@ class OCCIServer < CloudServer
 
         return to_occi_xml(user, 200)
     end
-    
-    def get_computes_types
-        etc_location=ONE_LOCATION ? ONE_LOCATION+"/etc" : "/etc/one"
-        begin
-            xml_response = "<ALLOWED_COMPUTE_TYPES>\n"
-            
-            Dir[etc_location + "/occi_templates/**"].each{| filename |
-                next if File.basename(filename) == "common.erb"
-                xml_response += "\t<COMPUTE_TYPE>"
-                xml_response += "\t\t<NAME>#{File.basename(filename)[0..-5]}</NAME>"
-                file = File.open(filename, "r")
-                file.each_line{|line|
-                    next if line.match(/^#/)
-                    match=line.match(/^(.*)=(.*)/)
-                    next if !match 
-                    case match[1].strip
-                        when "NAME"
-                            xml_response += "\t\t<NAME>#{match[2].strip}</NAME>"                            
-                        when "CPU"
-                            xml_response += "\t\t<vCPU>#{match[2].strip}</vCPU>"
-                        when "MEMORY"
-                            xml_response += "\t\t<vMEM>#{match[2].strip}</vMEM>"  
-                    end                              
-                }
-                xml_response += "\t</COMPUTE_TYPE>"
-            }
-            
-            xml_response += "</ALLOWED_COMPUTE_TYPES>"
-
-            return xml_response, 200
-        rescue Exception  => e
-            return "Error getting the instance types. Reason: #{e.message}", 500
-        end        
-    end
 end
diff --git a/src/cloud/occi/lib/VirtualMachineOCCI.rb b/src/cloud/occi/lib/VirtualMachineOCCI.rb
index 1f00212020..73274ba9b0 100755
--- a/src/cloud/occi/lib/VirtualMachineOCCI.rb
+++ b/src/cloud/occi/lib/VirtualMachineOCCI.rb
@@ -26,7 +26,7 @@ class VirtualMachineOCCI < VirtualMachine
             <MEMORY><%= self['TEMPLATE/MEMORY'] %></MEMORY>
             <NAME><%= self.name%></NAME>
             <% if self['TEMPLATE/INSTANCE_TYPE'] %>
-            <INSTANCE_TYPE><%= self['TEMPLATE/INSTANCE_TYPE'] %></INSTANCE_TYPE>
+            <INSTANCE_TYPE href="<%= base_url %>/instance_type/<%= self['TEMPLATE/INSTANCE_TYPE'] %>"><%= self['TEMPLATE/INSTANCE_TYPE'] %></INSTANCE_TYPE>
             <% end %>
             <STATE><%= self.state_str %></STATE>
             <% self.each('TEMPLATE/DISK') do |disk| %>
@@ -84,10 +84,14 @@ class VirtualMachineOCCI < VirtualMachine
         end
 
         if @vm_info != nil
-            itype = @vm_info['INSTANCE_TYPE']
+            if href = @vm_info.attr('INSTANCE_TYPE','href')
+                @itype = href.split('/').last
+            else
+                @itype = @vm_info['INSTANCE_TYPE']
+            end
 
-            if itype != nil and types[itype.to_sym] != nil
-                @template = base + "/#{types[itype.to_sym][:template]}"
+            if @itype != nil and types[@itype.to_sym] != nil
+                @template = base + "/#{types[@itype.to_sym][:template]}"
             end
         end
 
diff --git a/src/cloud/occi/lib/occi-server.rb b/src/cloud/occi/lib/occi-server.rb
index e650e861cd..b2675a005d 100755
--- a/src/cloud/occi/lib/occi-server.rb
+++ b/src/cloud/occi/lib/occi-server.rb
@@ -128,10 +128,20 @@ end
 # Actions
 ##############################################################################
 
+get '/' do
+    result,rc = @occi_server.get_collections(request)
+    treat_response(result,rc)
+end
+
 ###################################################
 # Pool Resources methods
 ###################################################
 
+get '/instance_type' do
+    result,rc = @occi_server.get_instance_types(request)
+    treat_response(result,rc)
+end
+
 post '/compute' do
    result,rc = @occi_server.post_compute(request)
    treat_response(result,rc)
@@ -172,7 +182,7 @@ end
 ###################################################
 
 get '/compute/:id' do
-    if params[:id] == "types" 
+    if params[:id] == "types"
         result,rc = @occi_server.get_computes_types
     else
         result,rc = @occi_server.get_compute(request, params)