diff --git a/helper/ccnx-encoding-helper.cc b/helper/ccnx-encoding-helper.cc
index 3dd7ad6..ded1627 100644
--- a/helper/ccnx-encoding-helper.cc
+++ b/helper/ccnx-encoding-helper.cc
@@ -29,107 +29,6 @@
 
 namespace ns3 {
 
-#define CCN_TT_BITS 3
-#define CCN_TT_MASK ((1 << CCN_TT_BITS) - 1)
-#define CCN_MAX_TINY ((1 << (7-CCN_TT_BITS)) - 1)
-#define CCN_TT_HBIT ((unsigned char)(1 << 7))
-
-size_t
-CcnxEncodingHelper::AppendBlockHeader (Buffer::Iterator start, size_t val, CcnbParser::ccn_tt tt)
-{
-  unsigned char buf[1+8*((sizeof(val)+6)/7)];
-  unsigned char *p = &(buf[sizeof(buf)-1]);
-  size_t n = 1;
-  p[0] = (CCN_TT_HBIT & ~CcnbParser::CCN_CLOSE) |
-  ((val & CCN_MAX_TINY) << CCN_TT_BITS) |
-  (CCN_TT_MASK & tt);
-  val >>= (7-CCN_TT_BITS);
-  while (val != 0) {
-    (--p)[0] = (((unsigned char)val) & ~CCN_TT_HBIT) | CcnbParser::CCN_CLOSE;
-    n++;
-    val >>= 7;
-  }
-  start.Write (p,n);
-  return n;
-}
-
-size_t
-CcnxEncodingHelper::AppendNumber (Buffer::Iterator start, uint32_t number)
-{
-  std::ostringstream os;
-  os << number;
-
-  size_t written = 0;
-  written += AppendBlockHeader (start, os.str().size(), CcnbParser::CCN_UDATA);
-  written += os.str().size();
-  start.Write (reinterpret_cast<const unsigned char*>(os.str().c_str()), os.str().size());
-
-  return written;
-}
-
-  
-size_t
-CcnxEncodingHelper::CcnxEncodingHelper::AppendCloser (Buffer::Iterator start)
-{
-  start.WriteU8 (CcnbParser::CCN_CLOSE);
-  return 1;
-}
-
-size_t
-CcnxEncodingHelper::AppendNameComponents (Buffer::Iterator start, const CcnxNameComponents &name)
-{
-  size_t written = 0;
-  BOOST_FOREACH (const std::string &component, name.GetComponents())
-    {
-      written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_Component,
-                                   reinterpret_cast<const uint8_t*>(component.c_str()), component.size());
-    }
-  return written;
-}
-
-size_t
-CcnxEncodingHelper::AppendTimestampBlob (Buffer::Iterator start, Time time)
-{
-  // the original function implements Markers... thought not sure what are these markers for...
-
-  // Determine miminal number of bytes required to store the timestamp
-  int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
-  intmax_t ts = time.ToInteger (Time::S) >> 4;
-  for (;  required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
-     required_bytes++;
-  
-  size_t len = AppendBlockHeader(start, required_bytes, CcnbParser::CCN_BLOB);
-
-  // write part with seconds
-  ts = time.ToInteger (Time::S) >> 4;
-  for (int i = 0; i < required_bytes - 2; i++)
-    start.WriteU8 ( ts >> (8 * (required_bytes - 3 - i)) );
-
-  /* arithmetic contortions are to avoid overflowing 31 bits */
-  ts = ((time.ToInteger (Time::S) & 15) << 12) + ((time.ToInteger (Time::NS) / 5 * 8 + 195312) / 390625);
-  for (int i = required_bytes - 2; i < required_bytes; i++)
-    start.WriteU8 ( ts >> (8 * (required_bytes - 1 - i)) );
-  
-  return len + required_bytes;
-}
-
-size_t
-CcnxEncodingHelper::AppendTaggedBlob (Buffer::Iterator start, CcnbParser::ccn_dtag dtag,
-                  const uint8_t *data, size_t size)
-{
-  size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
-  if (size>0)
-    {
-      written += AppendBlockHeader (start, size, CcnbParser::CCN_BLOB);
-      start.Write (data, size);
-      written += size;
-    }
-  written += AppendCloser (start);
-
-  return written;
-}
-
-
 size_t
 CcnxEncodingHelper::Serialize (Buffer::Iterator start, const CcnxInterestHeader &interest)
 {
@@ -152,7 +51,7 @@
       written += AppendNumber (start, interest.GetMaxSuffixComponents ());
       written += AppendCloser (start);
     }
-  if (interest.GetExclude().size() > 0)
+  if (interest.IsEnabledExclude() && interest.GetExclude().size() > 0)
     {
       written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Exclude, CcnbParser::CCN_DTAG); // <Exclude>
       written += AppendNameComponents (start, interest.GetExclude());                // <Component>...</Component>...
@@ -195,6 +94,67 @@
 }
 
 size_t
+CcnxEncodingHelper::GetSerializedSize (const CcnxInterestHeader &interest)
+{
+  size_t written = 0;
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Interest); // <Interest>
+  
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Name); // <Name>
+  written += EstimateNameComponents (interest.GetName()); // <Component>...</Component>...
+  written += 1; // </Name>
+
+  if (interest.GetMinSuffixComponents() >= 0)
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_MinSuffixComponents);
+      written += EstimateNumber (interest.GetMinSuffixComponents ());
+      written += 1;
+    }
+  if (interest.GetMaxSuffixComponents() >= 0)
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_MaxSuffixComponents);
+      written += EstimateNumber (interest.GetMaxSuffixComponents ());
+      written += 1;
+    }
+  if (interest.IsEnabledExclude() && interest.GetExclude().size() > 0)
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Exclude);
+      written += EstimateNameComponents (interest.GetExclude());                // <Component>...</Component>...
+      written += 1;                                  // </Exclude>
+    }
+  if (interest.IsEnabledChildSelector())
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_ChildSelector);
+      written += EstimateNumber (1);
+      written += 1;
+    }
+  if (interest.IsEnabledAnswerOriginKind())
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_AnswerOriginKind);
+      written += EstimateNumber (1);
+      written += 1;
+    }
+  if (interest.GetScope() >= 0)
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Scope);
+      written += EstimateNumber (interest.GetScope ());
+      written += 1;
+    }
+  if (!interest.GetInterestLifetime().IsZero())
+    {
+      written += EstimateBlockHeader (CcnbParser::CCN_DTAG_InterestLifetime);
+      written += EstimateTimestampBlob (interest.GetInterestLifetime());
+      written += 1;
+    }
+  if (interest.GetNonce()>0)
+    {
+      written += EstimateTaggedBlob (CcnbParser::CCN_DTAG_Nonce, sizeof(uint32_t));
+    }
+  written += 1; // </Interest>
+
+  return written;
+}
+
+size_t
 CcnxEncodingHelper::Serialize (Buffer::Iterator start, const CcnxContentObjectHeader &contentObject)
 {
   size_t written = 0;
@@ -229,4 +189,197 @@
   return written;
 }
 
+size_t
+CcnxEncodingHelper::GetSerializedSize (const CcnxContentObjectHeader &contentObject)
+{
+  size_t written = 0;
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_ContentObject); // <ContentObject>
+
+  // fake signature
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Signature); // <Signature>
+  // Signature ::= DigestAlgorithm? 
+  //               Witness?         
+  //               SignatureBits   
+  written += EstimateTaggedBlob (CcnbParser::CCN_DTAG_SignatureBits, 0);      // <SignatureBits />
+  written += 1;                                    // </Signature>  
+
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Name);    // <Name>
+  written += EstimateNameComponents (contentObject.GetName()); //   <Component>...</Component>...
+  written += 1;                                  // </Name>  
+
+  // fake signature
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_SignedInfo); // <SignedInfo>
+  // SignedInfo ::= PublisherPublicKeyDigest
+  //                Timestamp
+  //                Type?
+  //                FreshnessSeconds?
+  //                FinalBlockID?
+  //                KeyLocator?
+  written += EstimateTaggedBlob (CcnbParser::CCN_DTAG_PublisherPublicKeyDigest, 0); // <PublisherPublicKeyDigest />
+  written += 1;                                     // </SignedInfo>
+
+  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Content); // <Content>
+
+  // there is no closing tag !!!
+  return written;
+}
+
+//////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////
+
+#define CCN_TT_BITS 3
+#define CCN_TT_MASK ((1 << CCN_TT_BITS) - 1)
+#define CCN_MAX_TINY ((1 << (7-CCN_TT_BITS)) - 1)
+#define CCN_TT_HBIT ((unsigned char)(1 << 7))
+
+size_t
+CcnxEncodingHelper::AppendBlockHeader (Buffer::Iterator &start, size_t val, CcnbParser::ccn_tt tt)
+{
+  unsigned char buf[1+8*((sizeof(val)+6)/7)];
+  unsigned char *p = &(buf[sizeof(buf)-1]);
+  size_t n = 1;
+  p[0] = (CCN_TT_HBIT & ~CcnbParser::CCN_CLOSE) |
+  ((val & CCN_MAX_TINY) << CCN_TT_BITS) |
+  (CCN_TT_MASK & tt);
+  val >>= (7-CCN_TT_BITS);
+  while (val != 0) {
+    (--p)[0] = (((unsigned char)val) & ~CCN_TT_HBIT) | CcnbParser::CCN_CLOSE;
+    n++;
+    val >>= 7;
+  }
+  start.Write (p,n);
+  return n;
+}
+
+size_t
+CcnxEncodingHelper::EstimateBlockHeader (size_t value)
+{
+  value >>= (7-CCN_TT_BITS);
+  size_t n = 1;
+  while (value>0)
+    {
+      value >>= 7;
+      n++;
+    }
+  return n;
+}
+
+size_t
+CcnxEncodingHelper::AppendNumber (Buffer::Iterator &start, uint32_t number)
+{
+  std::ostringstream os;
+  os << number;
+
+  size_t written = 0;
+  written += AppendBlockHeader (start, os.str().size(), CcnbParser::CCN_UDATA);
+  written += os.str().size();
+  start.Write (reinterpret_cast<const unsigned char*>(os.str().c_str()), os.str().size());
+
+  return written;
+}
+
+size_t
+CcnxEncodingHelper::EstimateNumber (uint32_t number)
+{
+  std::ostringstream os;
+  os << number;
+  return EstimateBlockHeader (os.str ().size ()) + os.str ().size ();
+}
+  
+size_t
+CcnxEncodingHelper::AppendCloser (Buffer::Iterator &start)
+{
+  start.WriteU8 (CcnbParser::CCN_CLOSE);
+  return 1;
+}
+
+size_t
+CcnxEncodingHelper::AppendNameComponents (Buffer::Iterator &start, const CcnxNameComponents &name)
+{
+  size_t written = 0;
+  BOOST_FOREACH (const std::string &component, name.GetComponents())
+    {
+      written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_Component,
+                                   reinterpret_cast<const uint8_t*>(component.c_str()), component.size());
+    }
+  return written;
+}
+
+size_t
+CcnxEncodingHelper::EstimateNameComponents (const CcnxNameComponents &name)
+{
+  size_t written = 0;
+  BOOST_FOREACH (const std::string &component, name.GetComponents())
+    {
+      written += EstimateTaggedBlob (CcnbParser::CCN_DTAG_Component, component.size());
+    }
+  return written;
+}
+
+size_t
+CcnxEncodingHelper::AppendTimestampBlob (Buffer::Iterator &start, const Time &time)
+{
+  // the original function implements Markers... thought not sure what are these markers for...
+
+  // Determine miminal number of bytes required to store the timestamp
+  int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
+  intmax_t ts = time.ToInteger (Time::S) >> 4;
+  for (;  required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
+     required_bytes++;
+  
+  size_t len = AppendBlockHeader(start, required_bytes, CcnbParser::CCN_BLOB);
+
+  // write part with seconds
+  ts = time.ToInteger (Time::S) >> 4;
+  for (int i = 0; i < required_bytes - 2; i++)
+    start.WriteU8 ( ts >> (8 * (required_bytes - 3 - i)) );
+
+  /* arithmetic contortions are to avoid overflowing 31 bits */
+  ts = ((time.ToInteger (Time::S) & 15) << 12) +
+       (((time.ToInteger (Time::NS) % 1000000000) / 5 * 8 + 195312) / 390625);
+  for (int i = required_bytes - 2; i < required_bytes; i++)
+    start.WriteU8 ( ts >> (8 * (required_bytes - 1 - i)) );
+  
+  return len + required_bytes;
+}
+
+size_t
+CcnxEncodingHelper::EstimateTimestampBlob (const Time &time)
+{
+  int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
+  intmax_t ts = time.ToInteger (Time::S) >> 4;
+  for (;  required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
+     required_bytes++;
+
+  return EstimateBlockHeader (required_bytes) + required_bytes;
+}
+
+size_t
+CcnxEncodingHelper::AppendTaggedBlob (Buffer::Iterator &start, CcnbParser::ccn_dtag dtag,
+                  const uint8_t *data, size_t size)
+{
+  size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
+  /* 2 */
+  if (size>0)
+    {
+      written += AppendBlockHeader (start, size, CcnbParser::CCN_BLOB);
+      start.Write (data, size);
+      written += size;
+      /* size */
+    }
+  written += AppendCloser (start);
+  /* 1 */
+
+  return written;
+}
+
+size_t
+CcnxEncodingHelper::EstimateTaggedBlob (CcnbParser::ccn_dtag dtag, size_t size)
+{
+  return EstimateBlockHeader (dtag) + EstimateBlockHeader (size) + size + 1;
+}
+
+
+
 } // namespace ns3