diff --git a/src/common/packet.cc b/src/common/packet.cc
index cda5fbe8e..f2ba95ea8 100644
--- a/src/common/packet.cc
+++ b/src/common/packet.cc
@@ -200,7 +200,7 @@ Packet::RemoveHeader (Header &header)
   return deserialized;
 }
 uint32_t
-Packet::PeekHeader (Header &header)
+Packet::PeekHeader (Header &header) const
 {
   NS_LOG_FUNCTION (this << &header);
   uint32_t deserialized = header.Deserialize (m_buffer.Begin ());
diff --git a/src/common/packet.h b/src/common/packet.h
index 428297028..454da94b6 100644
--- a/src/common/packet.h
+++ b/src/common/packet.h
@@ -210,7 +210,7 @@ public:
    * \param header a reference to the header to read from the internal buffer.
    * \returns the number of bytes read from the packet.
    */  
-  uint32_t PeekHeader (Header &header);
+  uint32_t PeekHeader (Header &header) const;
   /**
    * Add trailer to this packet. This method invokes the
    * Trailer::GetSerializedSize and Trailer::Serialize