Network Working Group                                        J. Pezeshki
Internet-Draft                                                E. Ertekin
Expires: August 28, 2007
Intended status: Experimental                                  R. Jasani
Expires: December 3, 2007                                    C. Christou
                                                     Booz Allen Hamilton
                                                       February 24,
                                                            June 1, 2007

    IKEv2 Extensions to Support Robust Header Compression over IPsec (HCoIPsec)

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This Internet-Draft will expire on August 28, December 3, 2007.

Copyright Notice

   Copyright (C) The IETF Trust (2007).


   When using Robust Header Compression (HC) schemes (e.g.  ROHC (RoHC [ROHC]) in conjunction
   with IPsec [IPSEC] (i.e.  [HCOIPSEC])  [RoHCOIPSEC]) a mechanism is needed to
   negotiate ROHC RoHC configuration parameters between end-points prior to
   operation.  Internet Key Exchange (IKE) is a mechanism which can be
   leveraged to handle these negotiations.  This document specifies
   extensions to Internet Key Exchange (IKEv2 [IKEV2]) that will allow ROHC
   RoHC and its associated configuration parameters to be negotiated for
   IPsec security associations (SAs).

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Header Compression  RoHC Channel Negotiation . . . . . . . . . . . . . . . . . . .  3
     2.1.  Negotiation of Header Compression RoHC Channel Parameters . . . . . . . . . .  3
       2.1.1.  Profiles Suboption . . . . . . . . . . . . . . . . . .  6
   3.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
   5.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     6.1.  Normative References . . . . . . . . . . . . . . . . . . .  8
     6.2.  Informative References . . . . . . . . . . . . . . . . . .  8
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  8
   Intellectual Property and Copyright Statements . . . . . . . . . . 10

1.  Introduction

   Increased packet header overhead due to IPsec protection can result
   in inefficient utilization of bandwidth.  Coupling HC RoHC with IPsec
   offers an efficient way to transfer protected IP traffic.

   HC schemes require

   For proper RoHCoIPsec [ROHCOIPSEC] operation, RoHC requires
   configuration parameters to be negotiated between the compressor and
   decompressor, prior to operation.  Current specifications of hop-by-
   hop ROHC RoHC schemes negotiate these parameters through a link-layer
   protocol such as Point-to-Point Protocol (PPP) (i.e.  ROHC  RoHC over PPP
   [ROHCPPP]).  Similarly, key exchange protocols (e.g.  IKEv2) exist,
   which are
   commonly used to negotiate parameters between IPsec peers before a SA
   can be established.  This document proposes the use of
   IPsec's parameter negotiation mechanism, IKE, IKEv2 to
   handle ROHC RoHC channel configuration for HCoIPsec.  Various RoHCoIPsec, and details various
   extensions to IKEv2, designed IKEv2 which are intended to provide this functionality, are detailed within this document. functionality.

2.  Header Compression  RoHC Channel Negotiation

   The initialization of a ROHC RoHC session requires the negotiation of a
   set of configuration parameters (e.g. maximum context identifier
   length,  MAX_CID, etc.).  As such, a
   mechanism must exist for a ROHC RoHC enabled device to share a list of
   supported HC RoHC parameters with its peer, and for the peer to select
   the appropriate parameters from this list.

   Similarly, negotiable parameters must also be shared between IPsec
   peers before a SA can be established.  To perform this negotiation, a
   key exchange protocol, IKEv2, is commonly used.  IKEv2 is an
   extensible protocol that negotiates parameters via request/response
   message pairs (i.e. exchanges).

   A set of extensions to IKEv2 can be defined, which will allow for
   RoHC parameters to be negotiated during the creation and rekeying of
   Child SAs.  This new Notify payload will contain values for the set
   of ROHC RoHC parameters to be negotiated between the two ROHC RoHC peers.

2.1.  Negotiation of Header Compression RoHC Channel Parameters


   RoHC configuration parameters will be negotiated at either the
   establishment or rekeying of a Child SA.  Specifically, a Notify
   payload will be used during the IKE_AUTH and CREATE_CHILD_SA
   exchanges to negotiate the HCoIPsec RoHCoIPsec session.  The Notify payload
   sent by the initiator will contain the configuration parameters for
   ROHC RoHC scheme.  Upon receipt of the initiator's request, the
   responder will either ignore the payload (if it doesn't support ROHC RoHC
   or the proposed parameters) or respond with a Notify payload that
   contains the accepted negotiable RoHC channel parameters.

   A new Notify Message Type value, denoted ROHC_SUPPORTED, will be
   added to indicate that the Notify payload is conveying ROHC RoHC channel
   parameters.  As defined in [IPSEC], [IKEV2], the Notify payload is specified
   as follows:

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   ! Next Payload  !C!  RESERVED   !         Payload Length        !
   !  Protocol ID  !   SPI Size    !      Notify Message Type      !
   !                                                               !
   ~                        Notification Data                      ~
   !                                                               !

   Figure 1: Notify Payload

   To negotiate HCoIPsec, RoHCoIPsec, the values for the fields in the Notify
   payload are defined as follows:

   Next Payload (1 octet)
      Identifier for the payload type of the next payload in the
      message.  If the current payload is the last in the message, then
      this field will be 0.  The Next Payload value of the previous
      payload must be 41, indicating that this current payload is a
      Notify Payload.

   Critical (1 bit)
      This value is set to zero, indicating that the recipient must skip
      this payload if it does not understand the payload type code in
      the Next Payload field of the previous payload.

   RESERVED (7 bits)
      Must be sent as zero, and must be ignored on receipt.

   Payload Length (2 octets)
      Length in octets of the current payload, including the generic
      payload header. header (the generic payload header is defined in [IKEV2],
      section 3.2).

   Protocol ID (1 octet)
      If this notification concerns an existing SA, this field indicates
      the type of that SA (i.e.  IKE_SA, AH [AH], or ESP [ESP]).  Since
      the ROHC RoHC parameters are set at SA creation, and thus do not relate
      to an existing SA, this field must be set to zero.

   SPI Size (1 octet)
      Length in octets of the SPI as defined by the IPsec protocol ID.
      This value must be set to zero, since no SPI is applicable (ROHC (RoHC
      parameters are set at SA creation, thus the SPI has not been

   Notify Message Type (2 octets)
      Specifies the type of notification message.  This field must be
      set to ROHC_SUPPORTED.


   RoHC configuration parameters will be communicated via a new Notify
   message type, denoted ROHC_SUPPORTED.  The ROHC RoHC configuration
   parameters will be listed within the Notification Data field in the
   following format:

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   ! HC
   !ROHC PRMTR LNTH ! LNTH!            MAX_CID            !     MRRU...
       ...MRRU     !           MAX_HEADER          !               !
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
   !                                                               !
   ~                          suboptions...                        ~
   !                                                               !

   Figure 2: Notification Data field


      >= 7 (i.e. the combined length of HC RoHC PARAMETER LENGTH, MAX_CID,
      MRRU, and MAX_HEADER)

   MAX_CID (2 octets)
      The MAX_CID field indicates the maximum value of a context
      identifier.  This value must be at least 0 and at most 16383 (The
      value 0 implies having one context).

      Suggested value: 15

      Note: The value of LARGE_CIDS will be implicitly determined by
      this value (i.e. if MAX_CID is <= 15, LARGE_CIDS will be assumed
      to be 0).

   MRRU (2 octets)
      The MRRU field indicates the maximum reconstructed reception unit
      (see [ROHC], section 5.1.1).

      Suggested value: 0


      The MRRU value is used in conjunction with the segmentation
      protocol defined in ROHC. RoHC.  Since a HCoIPsec compressor and
      decompressor RoHCoIPsec will generally be separated by
      implemented across multiple link-layer "hops", segmentation will
      not normally be needed. required.  In these cases the MRRU value should will be
      set to zero, indicating that no segmented ROHC
      segmented-header packets segment headers are allowed on the

   MAX_HEADER (2 octets)
      The largest header size in octets that may be compressed.

      Suggested value: 168 octets

      Note: The MAX_HEADER parameter is not used for all ROHC RoHC profiles.
      If none of the ROHC RoHC profiles require this field, this value is

      The suboptions field consists of one or more suboptions.  Each
      suboption consists of a type field, a length field and zero or
      more parameter octets, as defined by the suboption type.  The
      value of the length field indicates the length of the suboption in
      its entirety, including the lengths of the type and length fields.

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   !     Type      !    Length     !  Parameters...

      Figure 3: Suboption

      Note: When a pair of SAs are created (one in each direction), the
      RoHC channel parameter FEEDBACK_FOR is set implicitly to the other
      SA of the pair (i.e. the SA pointing in the reverse direction).

2.1.1.  Profiles Suboption

   The set of profiles to be enabled on a Child SA is subject to

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   !     Type      !    Length     !  Profiles...

   Figure 4: Profiles suboption



      n octet-pairs in ascending order, each octet-pair specifying a
      RoHC profile supported.  Values negotiated are assigned in the
      RoHC profile identifiers registry [ROHCPROF].

3.  Security Considerations

   The negotiated HC schemes and RoHC parameters negotiated via IKEv2 do not add any new
   vulnerabilities beyond those associated with the normal operation of

4.  IANA Considerations

   This document defines a new Notify Message Type.  Therefore, if the
   proposal is accepted, IANA is
   requested to allocate on one value from the IKEv2 Notify Message Types
   registry to indicate ROHC_SUPPORTED.

5.  Acknowledgments

   The authors would like to thank Mr. Sean O'Keeffe, Mr. James Kohler,
   and Ms. Linda Noone of the Department of Defense, as well as Mr. Rich
   Espy of OPnet for their contributions and support in the development
   of this document.  The authors would also like to thank Mr. Tero
   Kivinen for providing his technical expertise for this document.  In
   addition, the authors would like to thank the following for their
   numerous reviews and comments to this document:

      Dr. Stephen Kent
      Dr. Carsten Bormann
      Mr. Lars-Erik Jonnson

   Finally, the authors would also like to thank Mr. Tom Conkle, Ms.

   Michele Casey, and Mr. Etzel Brower.

6.  References

6.1.  Normative References

   [ROHC]     Bormann, C., Burmeister, C., Degermark, M., Fukushima, H.,
              Hannu, H., Jonsson, L., Hakenberg, R., Koren, T., Le, K.,
              Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K.,
              Wiebke, T., Yoshimura, T., and H. Zheng, "RObust Header
              Compression (ROHC): Framework and four profiles: RTP, UDP,
              ESP, and uncompressed", RFC 3095, July 2001.

   [IPSEC]    Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.


              Ertekin, E., Christou, C., and R. Jasani, "Integration of
              Robust Header Compression over IPsec Security
              Associations", work in progress , February 2007. June 2006.

   [IKEV2]    Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
              RFC 4306, December 2005.

              "RObust Header Compression (ROHC) Profile Identifiers",
     , October 2005.

6.2.  Informative References

   [ROHCPPP]  Bormann, C., "Robust Header Compression (ROHC) over PPP",
              RFC 3241, April 2002.

   [AH]       Kent, S., "IP Authentication Header", RFC 4302,
              December 2005.

   [ESP]      Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005.

              "RObust Header Compression (ROHC) Profile Identifiers",
     , October 2005.

Authors' Addresses

   Jonah Pezeshki
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171

   Emre Ertekin
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


   Rohan Jasani
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


   Chris Christou
   Booz Allen Hamilton
   13200 Woodland Park Dr.
   Herndon, VA  20171


Full Copyright Statement

   Copyright (C) The IETF Trust (2007).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at


   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).