RFC 5858, "IPsec Extensions to Support Robust Header Compression over IPsec", May 2010

Errata ID: 2277
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Alfred Hoenes
Date Reported: 2010-05-19
Held for Document Update by: Lars Eggert

Section 4.2, pg. 7 says:

                BEFORE COMPRESSION AND APPLICATION OF ESP
                ----------------------------
          IPv4  |orig IP hdr  |     |      |
                |(any options)| TCP | Data |
                ----------------------------

                 AFTER ROHCOIPSEC COMPRESSION AND APPLICATION OF ESP
               ------------------------------------------------------
         IPv4  | new IP hdr  |     | Cmpr. |    | ROHC | ESP   | ESP|
               |(any options)| ESP | Hdr.  |Data| ICV  |Trailer| ICV|
               ------------------------------------------------------

   Figure 1.  Example of a ROHCoIPsec-Processed Packet

It should say:

                BEFORE COMPRESSION AND APPLICATION OF ESP
                ----------------------------
          IPv4  |orig IP hdr  |     |      |
                |(any options)| TCP | Data |
                ----------------------------

                 AFTER ROHCOIPSEC COMPRESSION AND APPLICATION OF ESP
               ------------------------------------------------------
         IPv4  | new IP hdr  |     | Cmpr. |    | ROHC | ESP   | ESP|
               |(any options)| ESP | Hdr.  |Data| ICV  |Trailer| ICV|
|              --------------------+===================+-------------

|  Figure 1.  Example of a ROHCoIPsec-Processed Packet ( +=====+ in
|             the diagram indicates the plaintext that undergoes ESP
|             protection; the packet actually contains the ciphertext)

Notes:

Rationale:
The lower part of Figure 1 misrepresents the packet format;
in the general case (not ESP NULL encryption), the structure
of the inner part of the ESP tunnel mode packet is hidden by
encryption.
The graphical presentation therefore might mislead the reader.
The suggested Corrected Text tries to avoid this by graphically
marking this part of the packet and adding a short note that the
diagram represents the plaintext structure only.

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