1.1 --- a/src/common/packet.h	Tue May 06 14:54:44 2008 -0700
     1.2 +++ b/src/common/packet.h	Tue May 06 14:54:52 2008 -0700
     1.3 @@ -98,7 +98,7 @@
     1.4  /**
     1.5   * \brief network packets
     1.6   *
     1.7 - * Each network packet contains a byte buffer, a list of tags, and
     1.8 + * Each network packet contains a byte buffer, a set of tags, and
     1.9   * metadata.
    1.10   *
    1.11   * - The byte buffer stores the serialized content of the headers and trailers 
    1.12 @@ -107,13 +107,10 @@
    1.13   * forces you to do this) which means that the content of a packet buffer
    1.14   * is expected to be that of a real packet.
    1.15   *
    1.16 - * - The list of tags stores an arbitrarily large set of arbitrary 
    1.17 - * user-provided data structures in the packet: only one instance of
    1.18 - * each type of data structure is allowed in a list of tags. 
    1.19 - * These tags typically contain per-packet cross-layer information or 
    1.20 - * flow identifiers. Each tag stored in the tag list can be at most
    1.21 - * 16 bytes big. Trying to attach bigger data structures will trigger
    1.22 - * crashes at runtime.
    1.23 + * - Each tag tags a subset of the bytes in the packet byte buffer with the 
    1.24 + * information stored in the tag. A classic example of a tag is a FlowIdTag 
    1.25 + * which contains a flow id: the set of bytes tagged by this tag implicitely 
    1.26 + * belong to the attached flow id.
    1.27   *
    1.28   * - The metadata describes the type of the headers and trailers which
    1.29   * were serialized in the byte buffer. The maintenance of metadata is

     2.1 --- a/src/common/tag-buffer.h	Tue May 06 14:54:44 2008 -0700
     2.2 +++ b/src/common/tag-buffer.h	Tue May 06 14:54:52 2008 -0700
     2.3 @@ -5,6 +5,12 @@
     2.4  
     2.5  namespace ns3 {
     2.6  
     2.7 +/**
     2.8 + * \brief read and write tag data
     2.9 + *
    2.10 + * This class allows subclasses of the ns3::Tag base class
    2.11 + * to serialize and deserialize their data.
    2.12 + */
    2.13  class TagBuffer
    2.14  {
    2.15  public:

     3.1 --- a/src/common/tag.h	Tue May 06 14:54:44 2008 -0700
     3.2 +++ b/src/common/tag.h	Tue May 06 14:54:52 2008 -0700
     3.3 @@ -7,13 +7,34 @@
     3.4  
     3.5  namespace ns3 {
     3.6  
     3.7 +/**
     3.8 + * \brief tag a set of bytes in a packet
     3.9 + *
    3.10 + * New kinds of tags can be created by subclassing this base class.
    3.11 + */
    3.12  class Tag : public ObjectBase
    3.13  {
    3.14  public:
    3.15    static TypeId GetTypeId (void);
    3.16  
    3.17 +  /**
    3.18 +   * \returns the number of bytes required to serialize the data of the tag.
    3.19 +   *
    3.20 +   * This method is typically invoked by Packet::AddTag just prior to calling
    3.21 +   * Tag::Serialize.
    3.22 +   */
    3.23    virtual uint32_t GetSerializedSize (void) const = 0;
    3.24 +  /**
    3.25 +   * \param i the buffer to write data into.
    3.26 +   *
    3.27 +   * Write the content of the tag in the provided tag buffer.
    3.28 +   */
    3.29    virtual void Serialize (TagBuffer i) const = 0;
    3.30 +  /**
    3.31 +   * \param i the buffer to read data from.
    3.32 +   *
    3.33 +   * Read the content of the tag from the provided tag buffer.
    3.34 +   */
    3.35    virtual void Deserialize (TagBuffer i) = 0;
    3.36  };
    3.37