diff --git a/src/mpValidations.py b/src/mpValidations.py
index 13cfda6..d8187a4 100644
--- a/src/mpValidations.py
+++ b/src/mpValidations.py
@@ -16,6 +16,9 @@ class Validation:
 		return self.__class__.__name__
 	def validate(self,value):
 		raise Exception("Method not implemented")
+	def setup(self):
+		raise Exception("Method not implemented")
+
 
 # checks a value passed is greater or equal (generic)
 class MinValueValidation(Validation):
@@ -56,13 +59,39 @@ class MinDelayBetweenValidation(Validation):
 		self.value = val
 		return self.compared<=val
 
-class AttributeMinimumDifferenceValidation(Validation):
-	def validate(self, flow_spec):
+class AttributeValidation(Validation):
+	def setup(self, flow_spec):
 		(yml ,trace) = flow_spec
 		[index0, index1] = yml["index"]
-		val = trace.get(index1, yml["attribute"]) - trace.get(index0, yml["attribute"]) 
-		self.value = val
-		return self.compared<=val
+		self.val0 = trace.get(index0, yml["attribute"]) 
+		self.val1 = trace.get(index1, yml["attribute"])
+
+class AttributeMinimumDifferenceValidation(AttributeValidation):
+	def validate(self, flow_spec):
+		self.setup(flow_spec)
+		self.value = self.val1 - self.val0
+		return self.compared<=self.value
+
+class AttributeMaximumDifferenceValidation(AttributeValidation):
+	def validate(self, flow_spec):
+		self.setup(flow_spec)
+		self.value = self.val1 - self.val0
+		return self.compared>=self.value
+
+
+class AttributeMinimumRatioValidation(AttributeValidation):
+	def validate(self, flow_spec):
+		self.setup(flow_spec)
+		self.value = float(self.val1)/+float(self.val1)
+		return self.compared<=self.value
+
+class AttributeMaximumRatioValidation(AttributeValidation):
+	def validate(self, flow_spec):
+		self.setup(flow_spec)
+		self.value = float(self.val1)/float(self.val0)
+		return self.compared>=self.value
+
+
 
 
 # Base class testing tcptrace results
diff --git a/src/tests/base/validation.yml b/src/tests/base/validation.yml
index 05690c6..2336c5a 100644
--- a/src/tests/base/validation.yml
+++ b/src/tests/base/validation.yml
@@ -20,6 +20,8 @@ tcptrace:
         desc: "Minimum 2 seconds delay between opening of first and second flow"
       # validates time between first packets of streams for which the index is passed. 
       # index is now a compound value, handled by the validate method of the class MinDelayBetweenValidation
+      # first index value is the base flow we compare to
+      # second index is the flow we want to validate
       - name: "min_delay_between"
         index:
           - 1
@@ -28,8 +30,20 @@ tcptrace:
         desc: "Minimum 1 second delay between opening of second and third flow"
       - name: "attribute_minimum_difference"
         attribute: "first_packet"
+        # first index value is the base flow we compare to
+        # second index is the flow we want to validate
         index:
           - 0
           - 1
         target: 2
         desc: "first packet delay 2nd flow"
+      - name: "attribute_maximum_ratio"
+        attribute: "total_packets_a2b"
+        # first index value is the base flow we compare to
+        # second index is the flow we want to validate
+        index:
+          - 0
+          - 1
+        # 5%
+        target: 0.05
+        desc: "a->b packet ration flow 2 compard to flow1"