Network Working Group E. Ertekin Internet-Draft C. Christou Expires:
May 6,August 28, 2006 R. Jasani Booz Allen Hamilton November 2, 2005February 24, 2006 Integration of Header Compression over IPsec Security Associations draft-ietf-rohc-hcoipsec-00draft-ietf-rohc-hcoipsec-01 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- Drafts. 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 http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 6,August 28, 2006. Copyright Notice Copyright (C) The Internet Society (2005).(2006). Abstract Internet Protocol security mechanisms, such as IP Security (IPsec) [IPSEC], provides various security services for IP traffic. However, the benefits offered by IPsec come at the cost of increased overhead. This document identifies a methodology for integratingset of work items that need to be completed to achieve the integration of header compression (HC) over IPsec (HCoIPsec). HCoIPsec proposes to reduce the amount of packet overhead associated with the transmission of traffic over tunnel mode security associations. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Problem Statement: Packet Overhead Associated with IPsec Tunnel-Mode SAs . . . . . . . . . . . . . . . . . . . . . . . 3 4.4 5. The Header Compression Solution . . . . . . . . . . . . . . . 4 5.5 6. Integration Methodology . . . . . . . . . . . . . . . . . . . 5 5.16 6.1. Work Assumptions . . . . . . . . . . . . . . . . . . . . . 6 5.26.2. Work Items . . . . . . . . . . . . . . . . . . . . . . . . 6 5.2.17 6.2.1. Header Compression Scheme-Specific Extensions . . . . 7 5.2.28 6.2.2. Initialization and Negotiation of Header Compression Channel . . . . . . . . . . . . . . . . . 7 5.2.38 6.2.3. Encapsulation and Identification of Header Compressed Packets . . . . . . . . . . . . . . . . . . 8 6.9 7. Candidate Compression Schemes . . . . . . . . . . . . . . . . 8 7.9 8. Example Operation . . . . . . . . . . . . . . . . . . . . . . 9 8.10 9. Future Work Items . . . . . . . . . . . . . . . . . . . . . . 11 8.112 9.1. HCoIPsec Transport Mode SAs . . . . . . . . . . . . . . . 11 8.2 Multiplexing of Compressed Packets in IPsec Tunnels . . .12 9.10. Security Considerations . . . . . . . . . . . . . . . . . . . 12 10.13 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 11.12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 12.13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 12.1. 14 13.1. Normative References . . . . . . . . . . . . . . . . . . . 13 12.214 13.2. Informative References . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 14. . 16 Intellectual Property and Copyright Statements . . . . . . . . 16. . 17 1. Introduction This document identifies a methodology forset of work items that need to be completed in order to achieve the integration of header compression (HC) over IPsec Security Associations (SAs) operating in tunnel mode. The goal of integrating HC with IPsec is to reduce the protocol overhead associated with packets traversing between IPsec SA endpoints. This goal can be achieved by compressing the upper layer protocols (e.g., RTP/UDP and TCP) and the inner IP header of packets, at the ingress of the IPsec tunnel, and decompression at the egress. To accomplish HCoIPsec, this document proposes the use of Internet Protocol Header Compression [IPHC], Compressed Real Time Protocol [CRTP], Enhanced Compressed Real Time Protocol [ECRTP], and Robust Header Compression [ROHC], to compress the inner headers of IP packets traversing within an IPsec tunnel. However, since these HC schemes operate on a hop-by-hop basis, several extensions need to be defined. This document details a methodologytechnique which will enable these traditional hop-by-hop HC schemes to be extended, and operate between IPsec SA endpoints. Currently, HCoIPsec primarily targets the application of HC to tunnel mode SAs as opposed to transport mode SAs. Transport mode SAs encrypt/authenticate only the payload of an IP packet, leaving the original IP header untouched. Intermediate routers subsequently use the original IP header to route the packet to a decryption device. Therefore, if HC were extended to operate between IPsec transport- mode SA endpoints, (de)compression functionality can be applied only to the transport layer headers and not the IP header. Since compression of transport layer headers alone does not provide substantial efficiency gains, it is not fullyintegrated into the HCoIPsec methodology.HCoIPsec. 2. Audience The target audience includes those who are involved with the design and development of HC schemes, and IPsec mechanisms. Since traditional IETF HC schemes are designed to operate on a hop-by-hop basis, they need to be modified to operate over IPsec SAs. Therefore, the authors target various HC and IPsec communities who may consider extending hop-by-hop HC schemes and IPsec protocols to meet the methodologyrequirements put forward in this document. Finally, this document is directed towards vendors developing IPsec devices which will be deployed in bandwidth-constrained, IP networks. 3. Terminology Terminology specific to discussion of HCoIPsec is introduced in this section. 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 in RFC 2119. Compressed Traffic Traffic that is processed by the compressor (compressed) using one of the existing profiles. Note: This includes packets that might be compressed using an "uncompressed" profile. Uncompressed Traffic Traffic that is not processed by the compressor. Instead, this type of traffic is bypassed by the HC process. HC Process Generic reference to either the compressor, decompressor, and any supporting header compression (HC) components. IPsec Process Generic reference to Internet Protocol Security (IPsec) process [IPSEC]. 4. Problem Statement: Packet Overhead Associated with IPsec Tunnel-Mode SAs IPsec mechanisms provide various security services for IP-based networks. For example, ESP offers data origin authentication, connectionless integrity, anti-replay service, and limited traffic flow confidentiality [ESP]. The benefits of IPsec mechanisms come at the cost of increased per- packet overhead in the network. For example, traffic flow confidentiality, which is generally implemented at security gateways, requires the tunneling of IP packets between the IPsec devices. IPsec tunnels may mask the source-destination patterns that an intruder may ascertain, but the benefit comes at the cost of extra per-packet overhead. An ESP tunnel mode SA applied to an IPv6 flow results in at least 50 bytes of additional overhead per packet. This additional overhead may be undesirable for many bandwidth-constrained wireless and/or Satellite Communications (SATCOM) networks, as these types of infrastructure are not overprovisioned. Consequently, the additional overhead incurred in an encryption-based environment may hinder the efficient utilization of bandwidth. In bandwidth-constrainedbandwidth-constrained, high bit error rate (BER) networks, IP Packet Loss Ratio (IPLR) can severely degrade end-host application performance. The traditional means for combating IPLR on high BER links has been Error Correction Codes (ECC). In addition, end-host applications may not have the luxury of sending packets with large payloads. This is due to the fact that large packets traversing high BER links result in high IP Packet Loss Ratio (IPLR). To reduce IPLR, end-host devices may reduce the size of packet payloads, which decreases the probability that a packet is lost due to a bit error. Reducing the size of packet payloads, however, increases the amount of overhead transmitted between the two end hosts. Moreover, if these packets traverse over an IPsec tunnel mode SA, the amount of overhead is further magnified. A mechanism is needed to reduce the overhead associated with such flows. 4.5. The Header Compression Solution IP HC schemes provide one mechanism to reduce packet overhead in an IP network. Schemes such as IPHC, CRTP, ECRTP and ROHC exploit inter-packet redundancies of network and transport-layer header fields of a flow to reduce the amount of redundant header data transmitted between two nodes. To apply HC schemes over IPsec SAs, several extensions to the existing schemes need to be developed. Existing HC schemes such as IPHC, CRTP, ECRTP and ROHC are designed to compress headers on a hop- by-hop basis. IPsec SAs, however, may be instantiated between IPsec devices functioning as gateways, with multiple intermediary nodes between the IPsec gateways. Therefore, to fully integrate HC with IPsec SAs, traditional hop-by-hop schemes need to be extended to operate between IPsec SA endpoints. The migration of traditional hop-by-hop HC schemes over IPsec SAs is simple, as SA endpoints provide source/destination pairs where (de)compression operations can take place. Compression in such a manner offers both a reduction of per-packet protocol overhead between the two SA endpoints, and does not require compression and decompression cycles at the intermediate network nodes between the IPsec devices. Since HC schemes will now essentially operate over multiple hops, it is imperative that the performance of the HC schemes is not severely impacted due to increased packet reordering and/or IPLR events between the compressor and decompressor. It should be noted that the notion of extending hop-by-hop HC schemes to operate over multiple hops is not new, as the HCoIPsec effort parallels other efforts such as ECRTP over MPLS [HCOMPLS]. Using the proposed architecture, outbound IP traffic processing at an IPsec device is augmented to compress appropriate packet headers, and subsequently encrypt and/or integrity-protect the packet. For tunnel mode SAs, compression may be applied to the transport layer protocol and the inner IP header. Inbound IP traffic processing at an IPsec device is modified in a similar fashion. For inbound packets, an IPsec device must first decrypt and/or integrity-check the packet. Then, the IPsec device implicitly determines whether the packet was received on a HC-enabled SA. If the packet was received over a HC-enabled SA, the decompression function takes place. Note: Compression of inner headers is completely independent from compression of the outer (e.g., ESP/IP) headers. Intermediate network nodes between IPsec endpoints may also compress the outer ESP/IP headers. Current HC schemes such as ROHC and IPHC contain the ability to compress these ESP/IP headers. Further discussion of hop-by-hop compression of the outer ESP/IP headers is out of the scope of this document. If IPsec NULL encryption is applied on packets, HC schemes may still be applied on the inner headers at the IPsec SA endpoints. Inbound and outbound packets are processed as described previously. In scenarios where NULL-encrypted packets traverse intermediate nodes between the IPsec SA endpoints, the intermediary nodes must not attempt to (de)compress the inner IP and/or transport layer headers on a hop-by-hop basis. 5.6. Integration Methodology The goal for HCoIPsec is to provide more efficient transport of IP packets between source and destination IPsec devicesdevices, via tunnel mode SAs, without compromising security services offered by IPsec. With this general goal in mind, Section 5.1 defines a set of work assumptions to guide the direction of the HCoIPsec solution. Based on these work assumptions, Section 5.2 defines work items which need to be addressed to achieve the HCoIPsec solution. 5.16.1. Work Assumptions a. HCoIPsec must use existing HC protocols (e.g., IPHC, CRTP, ECRTP, ROHC) to reduce the amount of overhead associated with packets traversing an IPsec tunnel-mode SA. b. HCoIPsec must execute (de)compression operations at IPsec SA endpoints, and must not perform (de)compression cycles at intermediate nodes between IPsec devices. c. HCoIPsec must be independent of the underlying link layer framing protocol (e.g., PPP). d. HCoIPsec must allow each SA to constitute a HC channel, enabling each SA to have its own CID space. e. An SA with HC enabled should not deliver a larger number of erroneous packets than the same SA with HC disabled. The motivation behind (c) comes from the realization that an SA may traverse multiple links, employing various framing protocols, and that the set of links (and thus framing protocols) may change during the lifetime of an SA. Therefore, link layer dependencies exhibited by traditional hop-by-hop HC schemes cannot be used in the HCoIPsec solution. 5.26.2. Work Items This section identifies several work items that need to be addressed to achieve HCoIPsec. The first work item encompasses the HC scheme- specific extensions needed to ensure that traditional hop-by-hop HC schemes will operate efficiently over IPsec SA endpoints: a. Header Compression Scheme-Specific Extensions: Any modifications needed to be made to existing HC schemes, which will facilitate their operation over IPsec SAs. (Section 5.2.1) Hop-by-hop HC schemes use the underlying link layer (e.g., PPP) to negotiate the HC channel parameters and to indicate the type of compressed packet the data-link layer frame is encapsulating. To remove HC scheme dependencies on the underlying link layer, two additional work items are proposed: b. Initialization and Negotiation of the Header Compression Channel: Mechanisms needed to initialize a HC channel and negotiate HC scheme parameters prior to operation. (Section 5.2.2) c. Encapsulation and Identification of Header Compressed Packets: Mechanisms that encapsulate and identify compressed header packets, as well as how these mechanisms will operate. (Section 5.2.3) 5.2.1 Header Compression Scheme-Specific Extensions a. HCoIPsec should minimize HC scheme performance degradation dueNote: (c) is still being discussed within the community and is subject to increased delays,change. More information about (c) can be found in the "Alternatives to Achieving HCoIPsec" internet-draft, a document being used to help resolve HCoIPsec discussions and issues in order to stabilize the HCoIPsec draft. 6.2.1. Header Compression Scheme-Specific Extensions a. HCoIPsec should minimize HC scheme performance degradation due to increased delays, packet loss, jitter, and reordering events between compressor and decompressor. b. HCoIPsec should minimize the amount of HC signaling between compressor and decompressor. c. HCoIPsec should support bi-directional communications functionality, used by certain HC schemes (e.g. ROHC bi- directional mode). The intention of (b) is to indicate that if a feedback channel from the decompressor to the compressor is not used sparingly, then the overall gains from HCoIPsec can be significantly reduced (even more so than hop-by-hop HC). For example, take the case where ROHC in bi- directional reliable mode is instantiated over an IPsec tunnel mode SA. Any feedback sent from the decompressor to the compressor may be tunneled, and therefore, the additional overhead incurred by tunneling the feedback will reduce the overall benefits of HC. Note that if a HCoIPsec session requires bidirectional communication between the compressor and the decompressor (e.g., a ROHC session operating in bidirectional-reliable mode, or bidirectional-optimistic mode, or ECRTP and CONTEXT_STATE packets), this may pose an issue, given that SAs are unidirectional, and that HCoIPsec defines a HC context to be specific to a given SA. Any feedback packet communicated from the HCoIPsec decompressor to the HCoIPsec compressor is over a separate SA back to the original IPsec device. To identify the stale context, the feedback packet must contain the context ID as well as an indication of the SA that the decompressor is associated to. This poses a problem for current HC algorithm feedback packets, which are not structured to carry the additional SA indication information. For example, current ECRTP feedback mechanisms (e.g., CONTEXT_STATE) only list the CIDs for which synchronization has been lost. If a bidirectional HC algorithm is to be integrated with IPsec, additional HC scheme-specific extensions must be defined to resolve this issue. 126.96.36.199.2. Initialization and Negotiation of Header Compression Channel Initialization of the HC channel parameters maywill be achieved manually (i.e., administratively configured for manual SAs), or maywill be performed by IPsec SA establishment protocols, e.g. IKE. During SA initialization, the IPsec SA establishment protocols will identify thetype of HC scheme configured for the SA, as well as the HC scheme's channel parameters.parameters will be identified. a. HCoIPsec may leverage IKE, IKEv2 to negotiate HC channel parameters (e.g., for ROHC, IKE(v2) shall initialize PROFILES, MAX_CID, MAX_HEADER, MRRU). b. HCoIPsec must allow packets with uncompressed headers and packets with compressed headers to traverse a single SA. "Packets with compressed headers" refer to packets which are selected to an HC- enabled SA, are passed to the compressor, and are actually compressed; "packets with uncompressed headers" refer to packets which are selected to an HC-enabled SA, are passed to the compressor, and are not "compressed" (e.g., ROHC compressor processes a packet with the uncompressed profile). Note: (b) is necessary in situations where a compressor--for one reason or another--cannotcompressor--can not compress a flow (e.g., a compressor supports strictly n compressed flows, and cannotcan not compress the n+1 flow that arrives). 5.2.3Note: (b) is still being discussed within the community and is subject to change. More information about (b) can be found in the "Alternatives to Achieving HCoIPsec" internet-draft, a document being used to help resolve HCoIPsec discussions and issues in order to stabilize the HCoIPsec draft. 6.2.3. Encapsulation and Identification of Header Compressed Packets For indication purposes, a one-byte header may be added to the compressed packet; this field will help the decompressor identify how to process the compressed packet. This one-byte header is only relevant to the HC compression and decompression processes, and is not used by IPsec.. a. HCoIPsec may introduce a new one-byte header tomust indicate the type of compressed packet (e.g., for ECRTP, COMPRESSED_RTP_8, COMPRESSED_RTP_16, CONTEXT_STATE, etc.) on a per packet basis. Note that ROHC indicates its own packet type within the protocol, and does not require a new one-byte header to indicate the type of compressed packet. 6.Note: Alternatives to using a "one-byte header" are still being discussed within the community, thus this section may change. More information can be found in the "Alternatives to Achieving HCoIPsec" internet-draft, a document being used to help resolve HCoIPsec discussions and issues in order to stabilize the HCoIPsec draft. 7. Candidate Compression Schemes IPHC can be used to compress TCP/IP headers for tunnel mode SAs. IPHC, however, has been identified as a HC scheme that performs poorly over long round trip time (RTT), high BER links [ROHC]. Extensions to IPHC to compress TCP/IP headers over an IPsec SA need to take into consideration longer RTTs, increased potential for packet reordering and IPLR between the compressor and decompressor. CRTP can be used to compress RTP/UDP/IP headers for tunnel mode SAs. CRTP, however, has also been identified as a HC scheme that performs poorly over long RTT, high BER links [CRTPE]. Recent modifications to the CRTP scheme, such as ECRTP, enables the CRTP HC scheme to tolerate long RTTs, packet loss, between compressor and decompressor. The reordering tolerance of ECRTP, however, needs to be evaluated, as detailed in [ECRTPE]. Such implementation aspects should be taken into consideration when extending ECRTP to operate between IPsec SA endpoints. ROHC, as defined in RFC 3095, provides a robust HC scheme that is designed for high BER, long RTT links. This makes ROHC another candidate header scheme to operate over IPsec tunnels. ROHC can be used to compress not only RTP/UDP/IP headers, but also TCP/IP headers, as defined in [ROHCTCP]. Similar to CRTP and IPHC, ROHC has been identified as vulnerable to packet reordering events between the compressor and decompressor[ROHCE]. Recent work [ROHCWEXT] suggests that the implementation aspects of ROHC can be modified to achieve tolerance to packet reordering events. Such implementation aspects should be taken into consideration when extending ROHC to operate between IPsec SA endpoints. The ability to tolerate these network characteristics is a necessity for any HCoIPsec scheme, and will be a factor in determining how efficiently the HC scheme operates over the IPsec tunnel-mode SAs. 7.8. Example Operation The basic operation of the HCoIPsec protocol is detailed in the following example. Assume there are two IPsec devices operating as security gateways. HCoIPsec leverages an SA establishment protocol (e.g., IKE, IKEv2) to negotiate the HC scheme, and channel parameters. For example, the MAX_CID, MRRU, MAX_HEADER, and PROFILES parameters will be negotiated for each IPsec SA which is capable of ROHC. For an IPsec SA that is ECRTP-enabled, channel parameters including F_MAX_PERIOD, F_MAX_TIME, and the ECRTP Compression Suboption will be initialized. For the following example, assume that a HC-enabledSA has been established. Outbound packet processing is as follows. The packet is initially processed as described in Steps 1-2, Section 5.1 of RFC 2401bis.4301. The SPD cache entry then maps the packet to a given SAD entry, which indicates the HC protocol enabled on the SA (in addition to mode, cryptographic algorithms, keys, etc.). If the SAD entry indicates that compression is disabled, then standard IPsec processing ensues, as described in Steps 3-4, Section 5.1 of RFC 2401bis.4301. If the SAD entry indicates that compression is enabled, the packet must be handed to the appropriate compressor, which executes the compression process. After the packet's header is compressed, the packet resumes IPsec processing as described in Step 3a, where standard IPsec ESP processing ensues (including packet encryption according to the SAD entry parameters, packet encapsulation with the outer ESP/IP header) and is subsequently passed to the outbound forwarding function, as described in Step 4 of RFC 2401bis.4301. Inbound packet processing is as follows. The packet is initially processed as described in Steps 1-3, Section 5.2 of RFC 2401bis;4301; subsequently (using the SAD entry selected in Step 3a), ESP processing is applied. Based on information retrieved from the SAD entry, it can also be determined whether traffic traversing the SA is compressed or not compressed. If the SAD entry indicates that compression is not enabled on the SA, then standard IPsec processing of the packet ensues, as described in Step 4, Section 5.2 of RFC 2401bis.4301. If compression is enabled on the SA, the packet is handed to the decompressor for "decompression". Once the packet is decompressed, the processing as described in Step 4, Section 5.2 of 2401bisRFC 4301 resumes (specifically "Then match the packet against the inbound selectors identified by the SAD..."). Figure 1 depicts the basic function of HCoIPsec: -- -- -- -- -- -- -- -- -- -- |ESP Tunnel Mode Security Association| | | | | V V +--------------+ +--------------+ | IPsec Device | +--+ +--+ | IPsec Device | | | | | | | | | +---| Compressor |-->|R1|-->|R2|-->| Decompressor |---+ | | | | | | | | | | | +--------------+ +--+ +--+ +--------------+ | | | | | | |-----------------| | | | | | | | V V V +-----------------+ +-----------------------+ +-----------------+ | | | | | | | | | | | | | | UDP | | | | E | ------------- | | | UDP | | |IP | / |Payload| |IP | S | |CID|Payload| | |IP | / |Payload| | | RTP | | | | P | ------------- | | | RTP | | | | | | | | | | | | | | +-----------------+ +-----------------------+ +-----------------+ | | |---ENCRYPTED---| | | Figure 1: Example operation of HCoIPsec. In the example scenario, note that the inbound and outbound packets are first mapped to an SA, and then subsequently mapped to a CID. This implies that the scope of each CID is contained within each SA. A CID value of 1 can be associated with multiple SAs; however, the context state information for CID 1 cannot be shared over multiple SAs. 8.9. Future Work Items 8.19.1. HCoIPsec Transport Mode SAs Many of the current HC profiles look to simultaneously compress network and transport layer headers of IP packets. This makes the extension of traditional HC schemes over transport-mode SAs more difficult. For the application of HC over transport mode SAs, traditional HC schemes may need to be extended to operate strictly on layer 4 (e.g., TCP, and/or RTP/UDP) headers. The methodology andspecification for HCoIPsec transport mode SAs is left for further study. 8.2 Multiplexing of Compressed Packets in IPsec Tunnels It should also be noted that a packet concatenation (or multiplexing) scheme may be added in conjunction to HCoIPsec to further reduce the overall overhead of packets traversing between IPsec devices. This type of functionality is similar to AAL2 voice trunking, where voice packets from different sources are placed into one cell [AAL2]. As described in [AAL2], a multiplexer concatenates cells until one of following two events occur: o the first event indicates that the maximum size of multiplexed cell is reached; o the second event indicates that a timer has expired: this timer provides an upper bound on the amount of delay a cell may exhibit. When either of these events are triggered, the multiplexer transmits the multiplexed cells. [TCRTP] is one proposal to reduce the packet overhead used between call gateways in an unencrypted network. In a similar fashion, if multiple compressed flows are mapped to one SA between two IPsec devices, then compressed packets MAY be concatenated with one another, encrypted, and subsequently tunneled to the destination IPsec device with one ESP/IP header. It should be noted, however, that a multiplexing functionality may be undesirable for the high BER networks, as multiplexing scheme may increase average packet sizes, which may result in a greater IPLR. The specification of such a protocol is left for further study. 9.10. Security Considerations A malfunctioning header compressor (i.e., the compressor located at the ingress of the IPsec tunnel)tunnel; used during outbound processing) has the ability to send packets to the decompressor (i.e., the decompressor located at the egress of the IPsec tunnel)tunnel; used during inbound processing) that do not match the original onespackets emitted from the end-hosts. In such a scenario, the invalid packets will pass thethrough inbound IPsec process,processing, and will subsequently be validly decompressed. Furthermore, an intruder who has the ability to arbitrarily inject packets between SA endpoints, and addresses these malicious packets to the encryption/decryption devices, has the ability to cause context corruption between the compressor and decompressor processes instantiated within the IPsec device (if the malicious packet passes through the decryption process). Such a scenario will result in a decreased efficiency between compressor and decompressor, and furthermore, may result in Denial of Service, as the decompression of a significant number of invalid packets may drain the resources of an IPsec device. Note: It should be noted, however, that these security issues are a direct offsetresult of IPsec vulnerabilities. 10.11. IANA Considerations None. 11.12. Acknowledgments The authors would like to thank Mr. Sean O'Keeffe, Mr. James Kohler, of the Department of Defense, and Mr. A. Rich Espy of OPnet for their contributions and support for developing this document. The authors would also like to thank Mr. Jan Vilhuber, Mr. Dan Wing, of Cisco Systems, Mr. Lars-Erik Jonsson and Mr. Kristopher Sandlund of Ericsson for their valuable contributions to this document. The authors would also like to thank Ms. Renee Esposito, Mr. Etzel Brower, Mr. Jigar Amroliwala, and Mr. Dwayne Corbin of Booz Allen Hamilton for their assistance in completing this work. 12.13. References 12.113.1. Normative References [IPSEC] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", work in progress , MarchRFC 4301, December 2005. [IPHC] Nordgren, M., Pink, B., and S. Pink, "IP Header Compression", RFC 2507, February 1999. [CRTP] Casner, S. and V. Jacobson, "Compressing IP/UDP/RTP Headers for Low-Speed Serial Links", RFC 2508, February 1999. [ECRTP] Koren, T. and et. al., "Compressing IP/UDP/RTP Headers on Links with High Delay, Packet Loss, and Reordering", RFC 3545, July 2003. [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. [ECRTPE] Knutsson, C., "Evaluation and Implemenation[sic] of Header Compression Algorithm ECRTP", November 2004. [ROHCTCP] Pelletier, G. and et. al, "Robust Header Compression: A Profile For TCP/IP (ROHC-TCP)", work in progress , February 2005.January 2006. [ROHCWEXT] Pelletier, G. and et. al, "ROHC over Channels That Can Reorder Packets", work in progress , February 2005. 12.2RFC 4224, January 2006. 13.2. Informative References [ESP] Kent, S., "IP Encapsulating Security Payload", work in progress , MarchRFC 4303, December 2005. [HCOMPLS] Ash, J. and et. al, "Protocol Extensions for Header Compression over MPLS", April 2005. [CRTPE] Degermark, M., Hannu, H., Jonsson, L., and K. Svanbro, "Evaluation of CRTP Performance over Cellular Radio Networks", IEEE Personal Communication Magazine , Volume 7, number 4, pp. 20-25, August 2000. [ROHCE] Ash, J. and et. al, "Requirements for ECRTP over MPLS", work in progress , December 2004.RFC 4247, November 2005. [AAL2] ITU-T, "B-ISDN ATM Adaptation layer specification: Type 2 AAL", I.363.2 , September 1997. [TCRTP] Thompson, B., "Tunneling of Multiplexed Compressed RTP", work in progress , September 2004.Authors' Addresses Emre Ertekin Booz Allen Hamilton 8283 Greensboro Drive McLean,13200 Woodland Park Dr. Herndon, VA 2210220171 US Email: email@example.com Chris Christou Booz Allen Hamilton 8283 Greensboro Drive McLean,13200 Woodland Park Dr. Herndon, VA 2210220171 US Email: firstname.lastname@example.org Rohan Jasani Booz Allen Hamilton 8283 Greensboro Drive McLean,13200 Woodland Park Dr. Herndon, VA 2210220171 US Email: email@example.com Intellectual Property Statement 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 http://www.ietf.org/ipr. 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 firstname.lastname@example.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005).(2006). 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society.