diff --git a/callagent/SIPDialog.st b/callagent/SIPDialog.st
index fc7c00a..3972154 100644
--- a/callagent/SIPDialog.st
+++ b/callagent/SIPDialog.st
@@ -83,7 +83,13 @@ Object subclass: SIPDialog [
         to_tag := aTag
     ]
 
+    callId: aCallId [
+        <category: 'private'>
+        call_id := aCallId
+    ]
+
     callId [
+        <category: 'accessing'>
         ^ call_id
     ]
 
@@ -155,27 +161,45 @@ Object subclass: SIPDialog [
         ^ dest_port
     ]
 
+    checkCompatible: other [
+        <category: 'private'>
+        "I am checking if the dialog is compatible."
+
+        self callId = other callId ifFalse: [
+            ^ self error: 'SIPDialog is not compatible due wrong CallID %1 %2.'
+                                % {self callId. other callId}.
+        ].
+
+        self from_tag = other from_tag ifFalse: [
+            ^ self error: 'SIPDialog is not compatible due wrong from tag %1 %2.'
+                                % {self from_tag. other from_tag}
+        ].
+
+        self to_tag isNil ifFalse: [
+            self to_tag = other to_tag ifFalse: [
+                ^ self error: 'SIPDialog is not compatible due to tag %1 %2.'
+                                % {self to_tag. other to_tag}
+            ].
+        ].
+    ]
+
     newFromRequest: aReq [
-        | to pos tag|
+        | to other |
         <category: 'handling'>
-        "I try to confirm a dialog"
+        "I try to confirm a dialog, i also verify that it is somehow compatible."
+
+        other := SIPDialog fromMessage: aReq.
+        self checkCompatible: other.
 
         "I am already confirmed."
         self isConfirmed ifTrue: [^self].
 
-        "I have a tag but I am not confirmed, create a copy and confirm"
-        to_tag ifNotNil: [
-            ^ self copy
-                confirm;
-                yourself].
-
         "There is no To... hmm return us"
         to := aReq parameter: 'To' ifAbsent: [^self].
-        (tag := to tag) isNil ifTrue: [
-            ^ self].
+        to tag isNil ifTrue: [^self].
 
         ^ self copy
-            toTag: tag;
+            toTag: to tag;
             confirm;
             yourself.
     ]
diff --git a/callagent/SIPParserTest.st b/callagent/SIPParserTest.st
index 09fbe35..abb07f7 100644
--- a/callagent/SIPParserTest.st
+++ b/callagent/SIPParserTest.st
@@ -74,4 +74,23 @@ PP.PPCompositeParserTest subclass: SIPParserTest [
             assert: dialog callId = 'MzY3NzE3ODgyNw__@xiaoyu';
             assert: dialog cseq = 1.
     ]
+
+    testDialogCompatible [
+        | initial_dialog dialog1 dialog2 |
+        initial_dialog := (SIPDialog
+                            fromUser: 'sip:1000@on-waves.com' host: '0.0.0.0' port: 5060)
+                            fromTag: 'MzQ4NTQ0MTg2NzIyNDEwNjkyNjY_';
+                            callId: 'MzY3NzE3ODgyNw__@xiaoyu';
+                            yourself.
+        self assert: initial_dialog isUnconfirmed.
+        self deny: initial_dialog isConfirmed.
+
+        dialog1 := initial_dialog newFromRequest: (self parse: self testResponseData).
+        self deny: initial_dialog == dialog1.
+        self assert: dialog1 isConfirmed.
+
+        dialog2 := dialog1 newFromRequest: (self parse: self testResponseData).
+        self assert: dialog1 == dialog2.
+        self assert: dialog2 isConfirmed.
+    ]
 ]
diff --git a/callagent/SIPTransactions.st b/callagent/SIPTransactions.st
index 76150d0..0f9ee5c 100644
--- a/callagent/SIPTransactions.st
+++ b/callagent/SIPTransactions.st
@@ -152,8 +152,6 @@ Object subclass: SIPTransaction [
             fail_time cancel.
         ].
 
-        "Verify the To/From tags here"
-
         "Store all dialogs.... and match them..."
         dialog := initial_dialog newFromRequest: aReq.