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Internet Engineering Task Force (IETF)                        E. ErtekinRequest for Comments: 5858                                   C. ChristouCategory: Standards Track                            Booz Allen HamiltonISSN: 2070-1721                                               C. Bormann                                                 Universitaet Bremen TZI                                                                May 2010IPsec Extensions to Support Robust Header Compression over IPsecAbstract   Integrating Robust Header Compression (ROHC) with IPsec (ROHCoIPsec)   offers the combined benefits of IP security services and efficient   bandwidth utilization.  However, in order to integrate ROHC with   IPsec, extensions to the Security Policy Database (SPD) and Security   Association Database (SAD) are required.  This document describes the   IPsec extensions required to support ROHCoIPsec.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc5858.Ertekin, et al.              Standards Track                    [Page 1]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010Copyright Notice   Copyright (c) 2010 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.   This document may contain material from IETF Documents or IETF   Contributions published or made publicly available before November   10, 2008.  The person(s) controlling the copyright in some of this   material may not have granted the IETF Trust the right to allow   modifications of such material outside the IETF Standards Process.   Without obtaining an adequate license from the person(s) controlling   the copyright in such materials, this document may not be modified   outside the IETF Standards Process, and derivative works of it may   not be created outside the IETF Standards Process, except to format   it for publication as an RFC or to translate it into languages other   than English.Table of Contents1. Introduction ....................................................32. Terminology .....................................................33. Extensions to IPsec Databases ...................................33.1. Security Policy Database (SPD) .............................43.2. Security Association Database (SAD) ........................54. Extensions to IPsec Processing ..................................64.1. Identification of Header-Compressed Traffic ................64.2. Verifying the Integrity of Decompressed Packet Headers .....64.2.1. ICV Computation and Integrity Verification ..........74.3. ROHC Segmentation and IPsec Tunnel MTU .....................84.4. Nested IPComp and ROHCoIPsec Processing ....................95. Security Considerations ........................................106. IANA Considerations ............................................107. Acknowledgments ................................................11Appendix A. ASN.1 Representation for ROHCoIPsec ...................128. References .....................................................148.1. Normative References ......................................148.2. Informative References ....................................14Ertekin, et al.              Standards Track                    [Page 2]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 20101.  Introduction   Using IPsec ([IPSEC]) protection offers various security services for   IP traffic.  However, these benefits come at the cost of additional   packet headers, which increase packet overhead.  By compressing the   inner headers of these packets, the integration of Robust Header   Compression (ROHC, [ROHC]) with IPsec (ROHCoIPsec, [ROHCOIPSEC]) can   reduce the packet overhead associated with IPsec-protected flows.   IPsec-protected traffic is carried over Security Associations (SAs),   whose parameters are negotiated on a case-by-case basis.  The   Security Policy Database (SPD) specifies the services that are to be   offered to IP datagrams, and the parameters associated with SAs that   have been established are stored in the Security Association Database   (SAD).  For ROHCoIPsec, various extensions to the SPD and SAD that   incorporate ROHC-relevant parameters are required.   In addition, three extensions to IPsec processing are required.   First, a mechanism for identifying ROHC packets must be defined.   Second, a mechanism to ensure the integrity of the decompressed   packet is needed.  Finally, the order of the inbound and outbound   processing must be enumerated when nesting IP Compression (IPComp   [IPCOMP]), ROHC, and IPsec processing.2.  Terminology   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described inRFC 2119 [BRA97].3.  Extensions to IPsec Databases   The following subsections specify extensions to the SPD and the SAD   that MUST be supported for ROHCoIPsec.  The ROHCoIPsec fields in the   SPD are used to populate the ROHCoIPsec parameters in the SAD during   the initialization or rekey of a child SA.   It is noted that these extensions do not have any implications on   existing SPD fields or SAD parameters.  Therefore, a ROHCoIPsec   implementation is backwards-compatible with an IPsec implementation   that does not support header compression.Appendix A provides an example ASN.1 representation of an SPD that is   extended to support ROHC.Ertekin, et al.              Standards Track                    [Page 3]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 20103.1.  Security Policy Database (SPD)   In general, the SPD is responsible for specifying the security   services that are offered to IP datagrams.  Entries in the SPD   specify how to derive the corresponding values for SAD entries.  To   support ROHC, the SPD is extended to include per-channel ROHC   parameters.  Together, the existing IPsec SPD parameters and the ROHC   parameters will dictate the security and header compression services   that are provided to packets.   The fields contained within each SPD entry are defined inRFC 4301   [IPSEC], Section 4.4.1.2.  To support ROHC, several processing info   fields are added to the SPD; these fields contain information   regarding the ROHC profiles and channel parameters supported by the   local ROHC instance.   If the processing action associated with the selector sets is   PROTECT, then the processing info must be extended with the following   ROHC channel parameters:      MAX_CID: This field indicates the highest context ID that will be      decompressed by the local decompressor.  MAX_CID MUST be at least      0 and at most 16383 (the value 0 implies having one context).      MRRU: The MRRU parameter indicates the size of the largest      reconstructed unit (in octets) that the local decompressor is      expected to reassemble from ROHC segments.  This size includes the      Cyclic Redundancy Check (CRC) and the ROHC Integrity Check Value      (ICV).  NOTE: Since in-order delivery of ROHC packets cannot be      guaranteed, the MRRU parameter SHOULD be set to 0 (as stated inSection 5.2.5.1 of RFC 5795 [ROHC] andSection 6.1 of RFC 5225      [ROHCV2]), which indicates that no segment headers are allowed on      the ROHCoIPsec channel.      PROFILES: This field is a list of ROHC profiles supported by the      local decompressor.  Possible values for this list are contained      in the "RObust Header Compression (ROHC) Profile Identifiers"      registry [ROHCPROF].   In addition to these ROHC channel parameters, a ROHC integrity   algorithm and a ROHC ICV Length field MUST be included within the   SPD:      ROHC INTEGRITY ALGORITHM: This field is a list of integrity      algorithms supported by the ROHCoIPsec instance.  This will be      used by the ROHC process to ensure that packet headers are      properly decompressed (seeSection 4.2).  Authentication      algorithms that MUST be supported are specified in theErtekin, et al.              Standards Track                    [Page 4]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010      "Authentication Algorithms" table inSection 3.1.1 ("ESP      Encryption and Authentication Algorithms") ofRFC 4835      [CRYPTO-ALG] (or its successor).      ROHC ICV LENGTH: This field specifies the length of the ICV that      is used in conjunction with the ROHC integrity algorithm.   Several other ROHC channel parameters are omitted from the SPD,   because they are set implicitly.  The omitted channel parameters are   LARGE_CIDS and FEEDBACK_FOR.  The LARGE_CIDS channel parameter MUST   be set based on the value of MAX_CID (i.e., if MAX_CID is <= 15,   LARGE_CIDS is assumed to be 0).  Finally, the ROHC FEEDBACK_FOR   channel parameter MUST be set to the ROHC channel associated with the   SA in the reverse direction.  If an SA in the reverse direction does   not exist, the FEEDBACK_FOR channel parameter is not set, and ROHC   MUST NOT operate in bi-directional Mode.3.2.  Security Association Database (SAD)   Each entry within the SAD defines the parameters associated with each   established SA.  Unless the "populate from packet" (PFP) flag is   asserted for a particular field, SAD entries are determined by the   corresponding SPD entries during the creation of the SA.   The data items contained within the SAD are defined inRFC 4301   [IPSEC], Section 4.4.2.1.  To support ROHC, the SAD must include a   "ROHC Data Item"; this data item contains parameters used by ROHC   instance.  The ROHC Data Item exists for both inbound and outbound   SAs.   The ROHC Data Item includes the ROHC channel parameters for the SA.   These channel parameters (i.e., MAX_CID, PROFILES, MRRU) are   enumerated above inSection 3.1.  For inbound SAs, the ROHC Data Item   MUST specify the ROHC channel parameters that are used by the local   decompressor instance; conversely, for outbound SAs, the ROHC Data   Item MUST specify the ROHC channel parameters that are used by local   compressor instance.   In addition to these ROHC channel parameters, the ROHC Data Item for   both inbound and outbound SAs MUST include three additional   parameters.  Specifically, these parameters store the integrity   algorithm, the algorithm's respective key, and the ICV length that is   used by the ROHC process (seeSection 3.2).  The integrity algorithm   and its associated key are used to calculate a ROHC ICV of the   specified length; this ICV is used to verify the packet headers post-   decompression.Ertekin, et al.              Standards Track                    [Page 5]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   Finally, for inbound SAs, the ROHC Data Item MUST include a   FEEDBACK_FOR parameter.  The parameter is a reference to a ROHC   channel in the opposite direction (i.e., the outbound SA) between the   same compression endpoints.  A ROHC channel associated with an   inbound SA and a ROHC channel associated with an outbound SA MAY be   coupled to form a bi-directional ROHC channel as defined in Sections   6.1 and 6.2 inRFC 3759 [ROHC-TERM].   "ROHC Data Item" values MAY be initialized manually (i.e.,   administratively configured for manual SAs), or initialized via a key   exchange protocol (e.g., IKEv2 [IKEV2]) that has been extended to   support the signaling of ROHC parameters [IKE-ROHC].4.  Extensions to IPsec Processing4.1.  Identification of Header-Compressed Traffic   A "ROHC" protocol identifier is used to identify header-compressed   traffic on a ROHC-enabled SA.  If an outbound packet has a compressed   header, the Next Header field of the security protocol header (e.g.,   Authentication Header (AH) [AH], Encapsulating Security Payload (ESP)   [ESP]) MUST be set to the "ROHC" protocol identifier.  If the packet   header has not been compressed by ROHC, the Next Header field does   not contain the "ROHC" protocol identifier.  Conversely, for an   inbound packet, the value of the security protocol Next Header field   MUST be checked to determine if the packet includes a ROHC header, in   order to determine if it requires ROHC decompression.   Use of the "ROHC" protocol identifier for purposes other than   ROHCoIPsec is currently not defined.  Future protocols that make use   of the allocation (e.g., other applications of ROHC in multi-hop   environments) require specification of the logical compression   channel between the ROHC compressor and decompressor.  In addition,   these specifications will require the investigation of the security   considerations associated with use of the "ROHC" protocol identifier   outside the context of the Next Header field of security protocol   headers.4.2.  Verifying the Integrity of Decompressed Packet Headers   As documented in Section 6.1.4 of [ROHCOIPSEC], ROHC is inherently a   lossy compression algorithm: the consequences of significant packet   reordering or loss between ROHC peers may include undetected   decompression failures, where erroneous packets are forwarded into   the protected domain.Ertekin, et al.              Standards Track                    [Page 6]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   To ensure that a decompressed header is identical to the original   header, ROHCoIPsec MAY use an additional integrity algorithm (and   respective key) to compute a second Integrity Check Value (ICV).   This ROHC ICV MUST be computed over the uncompressed IP header, as   well at the higher-layer headers and the packet payload.  When   computed, the ICV is appended to the ROHC-compressed packet.  At the   decompressor, the decompressed packet (including the uncompressed IP   header, higher-layer headers, and packet payload; but not including   the authentication data) will be used with the integrity algorithm   (and its respective key) to compute a value that will be compared to   the appended ICV.  If these values are not identical, the   decompressed packet MUST be dropped.   Figure 1 illustrates the composition of a ROHCoIPsec-processed IPv4   packet.  In the example, TCP/IP compression is applied, and the   packet is processed with tunnel mode ESP.                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   Note: At the decompressor, the ROHC ICV field is not included in the   calculation of the ROHC ICV.4.2.1.  ICV Computation and Integrity Verification   In order to correctly verify the integrity of the decompressed   packets, the processing steps for ROHCoIPsec MUST be implemented in a   specific order, as given below.   For outbound packets that are processed by ROHC and are IPsec-   protected:   o  Compute an ICV for the uncompressed packet with the negotiated      (ROHC) integrity algorithm and its respective key.   o  Compress the packet headers (as specified by the ROHC process).Ertekin, et al.              Standards Track                    [Page 7]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   o  Append the ICV to the compressed packet.   o  Apply AH or ESP processing to the packet, as specified in the      appropriate SAD entry.   For inbound packets that are to be decompressed by ROHC:   o  Apply AH or ESP processing, as specified in the appropriate SAD      entry.   o  Remove the ICV from the packet.   o  Decompress the packet header(s).   o  Compute an ICV for the decompressed packet with the negotiated      (ROHC) integrity algorithm and its respective key.   o  Compare the computed ICV to the original ICV calculated at the      compressor: if these two values differ, the packet MUST be      dropped; otherwise, resume IPsec processing.4.3.  ROHC Segmentation and IPsec Tunnel MTU   In certain scenarios, a ROHCoIPsec-processed packet may exceed the   size of the IPsec tunnel MTU.RFC 4301 [IPSEC] currently stipulates   the following for outbound traffic that exceeds the SA Path MTU   (PMTU):       Case 1: Original (cleartext) packet is IPv4 and has the Don't               Fragment (DF) bit set.  The implementation should               discard the packet and send a PMTU ICMP message.       Case 2: Original (cleartext) packet is IPv4 and has the DF               bit clear.  The implementation should fragment (before or               after encryption per its configuration) and then forward               the fragments.  It should not send a PMTU ICMP message.       Case 3: Original (cleartext) packet is IPv6.  The implementation               should discard the packet and send a PMTU ICMP message.   For the ROHCoIPsec processing model, there is one minor change to the   procedure stated above.  This change applies to pre-encryption   fragmentation for Case 2.  Since current ROHC compression profiles do   not support compression of IP packet fragments, pre-encryption   fragmentation MUST NOT occur before ROHC processing.Ertekin, et al.              Standards Track                    [Page 8]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   If the compressed packet exceeds the SA PMTU, and the MRRU is non-   zero, ROHC segmentation MAY be used to divide the packet, where each   segment conforms to the tunnel MTU.  ROHC segmentation MUST occur   before AH or ESP processing.  Because in-order delivery of ROHC   segments is not guaranteed, the use of ROHC segmentation is not   recommended.   If segmentation is applied, the process MUST account for the   additional overhead imposed by the IPsec process (e.g., AH or ESP   overhead, crypto synchronization data, the additional IP header,   etc.) such that the final IPsec-processed segments are less than the   tunnel MTU.  After segmentation, each ROHC segment is consecutively   processed by the appropriate security protocol (e.g., AH, ESP)   instantiated on the ROHC-enabled SA.  Since ROHC segments are   processed consecutively, the associated AH/ESP sequence number MUST   be incremented by one for each segment transmitted over the ROHC   channel.  As such, after all ROHC segments receive AH/ESP processing,   these segments can be identified (at the remote IPsec implementation)   by a range of contiguous AH/ESP sequence numbers.   For channels where the MRRU is non-zero, the ROHCoIPsec decompressor   MUST re-assemble the ROHC segments that are received.  To accomplish   this, the decompressor MUST identify the ROHC segments (as documented   inSection 5.2 of RFC 5795 [ROHC]), and attempt reconstruction using   the ROHC segmentation protocol (Section 5.2.5 of RFC 5795 [ROHC]).   To assist the reconstruction process, the AH/ESP sequence number   SHOULD be used to identify segments that may have been subject to   reordering.  If reconstruction fails, the packet MUST be discarded.   As stated inSection 3.2.1, if the ROHC integrity algorithm is used   to verify the decompression of packet headers, this ICV is appended   to the compressed packet.  If ROHC segmentation is performed, the   segmentation algorithm is executed on the compressed packet and the   appended ICV.  Note that the ICV is not appended to each ROHC   segment.   Under certain circumstances, IPsec implementations will not process   (or receive) unprotected ICMP messages, or they will not have a Path   MTU estimated value.  In these cases, the IPsec implementation SHOULD   NOT attempt to segment the ROHC-compressed packet, as it does not   have full insight into the path MTU in the unprotected domain.4.4.  Nested IPComp and ROHCoIPsec Processing   IPComp ([IPCOMP]) is another mechanism that can be implemented to   reduce the size of an IP datagram.  If IPComp and ROHCoIPsec are   implemented in a nested fashion, the following steps MUST be followed   for outbound and inbound packets.Ertekin, et al.              Standards Track                    [Page 9]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   For outbound packets that are to be processed by IPComp and ROHC:   o  The ICV is computed for the uncompressed packet, and the      appropriate ROHC compression profile is applied to the packet.   o  IPComp is applied, and the packet is sent to the IPsec process.   o  The security protocol is applied to the packet.   Conversely, for inbound packets that are to be both ROHC- and IPComp-   decompressed:   o  A packet received on a ROHC-enabled SA is IPsec-processed.   o  The datagram is decompressed based on the appropriate IPComp      algorithm.   o  The packet is sent to the ROHC module for header decompression and      integrity verification.5.  Security Considerations   A ROHCoIPsec implementer should consider the strength of protection   provided by the integrity check algorithm used to verify decompressed   headers.  Failure to implement a strong integrity check algorithm   increases the probability for an invalidly decompressed packet to be   forwarded by a ROHCoIPsec device into a protected domain.   The implementation of ROHCoIPsec may increase the susceptibility for   traffic flow analysis, where an attacker can identify new traffic   flows by monitoring the relative size of the encrypted packets (i.e.,   a group of "long" packets, followed by a long series of "short"   packets may indicate a new flow for some ROHCoIPsec implementations).   To mitigate this concern, ROHC padding mechanisms may be used to   arbitrarily add padding to transmitted packets to randomize packet   sizes.  This technique, however, reduces the overall efficiency   benefit offered by header compression.6.  IANA Considerations   IANA has allocated the value 142 to "ROHC" within the "Protocol   Numbers" registry [PROTOCOL].  This value will be used to indicate   that the next-level protocol header is a ROHC header.Ertekin, et al.              Standards Track                   [Page 10]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 20107.  Acknowledgments   The authors would like to thank Sean O'Keeffe, James Kohler, Linda   Noone of the Department of Defense, and Rich Espy of OPnet for their   contributions and support for developing this document.   The authors would also like to thank Yoav Nir and Robert A Stangarone   Jr.: both served as committed document reviewers for this   specification.   Finally, the authors would like to thank the following for their   numerous reviews and comments to this document:   o  Magnus Westerlund   o  Stephen Kent   o  Lars-Erik Jonsson   o  Carl Knutsson   o  Pasi Eronen   o  Jonah Pezeshki   o  Tero Kivinen   o  Joseph Touch   o  Rohan Jasani   o  Elwyn Davies   o  Bert WijnenErtekin, et al.              Standards Track                   [Page 11]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010Appendix A.  ASN.1 Representation for ROHCoIPsec   This appendix is included as an additional way to describe the   ROHCoIPsec parameters that are included in the IPsec SPD.  It uses   portions of the ASN.1 syntax provided inAppendix C of RFC 4301   [IPSEC].  In addition, several new structures are defined.   This syntax has been successfully compiled.  However, it is merely   illustrative and need not be employed in an implementation to achieve   compliance.   The "Processing" data structure, defined inAppendix C of RFC 4301,   is augmented to include a ROHC parameters element as follows:         Processing ::= SEQUENCE {             extSeqNum   BOOLEAN, -- TRUE 64 bit counter, FALSE 32 bit             seqOverflow BOOLEAN, -- TRUE rekey, FALSE terminate & audit             fragCheck   BOOLEAN, -- TRUE stateful fragment checking,                                  -- FALSE no stateful fragment checking             lifetime    SALifetime,             spi         ManualSPI,             algorithms  ProcessingAlgs,             tunnel      TunnelOptions OPTIONAL,             rohc        [7] RohcParams OPTIONAL         }   The following data structures describe these ROHC parameters:       RohcParams ::= SEQUENCE {           rohcEnabled         BOOLEAN, --  TRUE, hdr compr. is enabled                                        -- FALSE, hdr compr. is disabled           maxCID              INTEGER (0..16383),           mrru                INTEGER,           profiles            RohcProfiles,           rohcIntegAlg        RohcIntegAlgs,           rohcIntegICVLength  INTEGER           }       RohcProfiles ::= SET OF RohcProfileErtekin, et al.              Standards Track                   [Page 12]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010       RohcProfile ::= INTEGER {           rohcv1-rtp           (1),           rohcv1-udp           (2),           rohcv1-esp           (3),           rohcv1-ip            (4),           rohcv1-tcp           (6),           rohcv1-rtp-udpLite   (7),           rohcv1-udpLite       (8),           rohcv2-rtp         (257),           rohcv2-udp         (258),           rohcv2-esp         (259),           rohcv2-ip          (260),           rohcv2-rtp-udpLite (263),           rohcv2-udpLite     (264)           -- values taken from [ROHCPROF]           }       RohcIntegAlgs ::= SEQUENCE {           algorithm   RohcIntegAlgType,           parameters  ANY -- DEFINED BY algorithm -- OPTIONAL }       RohcIntegAlgType ::= INTEGER {           none                    (0),           auth-HMAC-MD5-96        (1),           auth-HMAC-SHA1-96       (2),           auth-DES-MAC            (3),           auth-KPDK-MD5           (4),           auth-AES-XCBC-96        (5),           auth-HMAC-MD5-128       (6),           auth-HMAC-SHA1-160      (7),           auth-AES-CMAC-96        (8),           auth-AES-128-GMAC       (9),           auth-AES-192-GMAC      (10),           auth-AES-256-GMAC      (11),           auth-HMAC-SHA2-256-128 (12),           auth-HMAC-SHA2-384-192 (13),           auth-HMAC-SHA2-512-256 (14)           --  tbd (15..65535)           -- values taken from "Transform Type 3 - Integrity           -- Algorithm Transform IDs" at [IKEV2-PARA]           }Ertekin, et al.              Standards Track                   [Page 13]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 20108.  References8.1.  Normative References   [IPSEC]       Kent, S. and K. Seo, "Security Architecture for the                 Internet Protocol",RFC 4301, December 2005.   [ROHC]        Sandlund, K., Pelletier, G., and L-E. Jonsson, "The                 RObust Header Compression (ROHC) Framework",RFC 5795,                 March 2010.   [IPCOMP]      Shacham, A., Monsour, B., Pereira, R., and M. Thomas,                 "IP Payload Compression Protocol (IPComp)",RFC 3173,                 September 2001.   [BRA97]       Bradner, S., "Key words for use in RFCs to Indicate                 Requirement Levels",BCP 14,RFC 2119, March 1997.   [ROHCV2]      Pelletier, G. and K. Sandlund, "RObust Header                 Compression Version 2 (ROHCv2): Profiles for RTP, UDP,                 IP, ESP and UDP-Lite",RFC 5225, April 2008.   [IKEV2]       Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",RFC 4306, December 2005.   [IKE-ROHC]    Ertekin, E., Christou, C., Jasani, R., Kivinen, T., and                 C. Bormann, "IKEv2 Extensions to Support Robust Header                 Compression over IPsec",RFC 5857, May 2010.   [AH]          Kent, S., "IP Authentication Header",RFC 4302,                 December 2005.   [ESP]         Kent, S., "IP Encapsulating Security Payload (ESP)",RFC 4303, December 2005.8.2.  Informative References   [ROHCOIPSEC]  Ertekin, E., Jasani, R., Christou, C., and C. Bormann,                 "Integration of Header Compression over IPsec Security                 Associations",RFC 5856, May 2010.   [ROHCPROF]    IANA, "RObust Header Compression (ROHC) Profile                 Identifiers", <http://www.iana.org>.   [CRYPTO-ALG]  Manral, V., "Cryptographic Algorithm Implementation                 Requirements for Encapsulating Security Payload (ESP)                 and Authentication Header (AH)",RFC 4835, April 2007.Ertekin, et al.              Standards Track                   [Page 14]

RFC 5858         IPsec Extensions to Support ROHCoIPsec         may 2010   [ROHC-TERM]   Jonsson, L-E., "Robust Header Compression (ROHC):                 Terminology and Channel Mapping Examples",RFC 3759,                 April 2004.   [PROTOCOL]    IANA, "Assigned Internet Protocol Numbers",                 <http://www.iana.org>.   [IKEV2-PARA]  IANA, "Internet Key Exchange Version 2 (IKEv2)                 Parameters", <http://www.iana.org>.Authors' Addresses   Emre Ertekin   Booz Allen Hamilton   5220 Pacific Concourse Drive, Suite 200   Los Angeles, CA  90045   US   EMail: ertekin_emre@bah.com   Chris Christou   Booz Allen Hamilton   13200 Woodland Park Dr.   Herndon, VA  20171   US   EMail: christou_chris@bah.com   Carsten Bormann   Universitaet Bremen TZI   Postfach 330440   Bremen  D-28334   Germany   EMail: cabo@tzi.orgErtekin, et al.              Standards Track                   [Page 15]