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Negotiation for IPv6 Datagram Compression Using IPv6 Control Protocol

The information below is for an old version of the document that is already published as an RFC.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 5172.
Author Srihari V. Varada
Last updated 2018-12-20 (Latest revision 2008-02-08)
RFC stream Internet Engineering Task Force (IETF)
Additional resources Mailing list discussion
Stream WG state (None)
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IESG IESG state RFC 5172 (Proposed Standard)
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Responsible AD Jari Arkko
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IPv6 Working Group                          S.Varada        (Editor) 
Internet Draft                              Transwitch       
Obsoletes: RFC 2472 (if approved)           February 2008    
Category: Standards track                                    
Expires: July 2008                                           
   Negotiation for IPv6 datagram compression using IPv6 Control Protocol 
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 
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      BCP 79. 
      Internet-Drafts are working documents of the Internet Engineering 
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Copyright Notice 
      Copyright (C) The IETF Trust (2008).   
      The Point-to-Point Protocol (PPP) provides a standard method of 
      encapsulating Network Layer protocol information over  
      point-to-point links.  PPP also defines an extensible Link Control  
      Protocol, and proposes a family of Network Control Protocols  
      (NCPs) for establishing and configuring different network-layer  

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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
      The IPv6 Control Protocol (IPV6CP), which is an NCP for a PPP 
      link, allows for the negotiation of desirable parameters for an 
      IPv6 interface over PPP. 
      This document defines the IPv6 datagram compression option that 
      can be negotiated by a node on the link through the IPV6CP.  
Table of Contents 
   1. Introduction...................................................2 
      1.1 Specification of Requirements..............................3 
   2. IPV6CP Configuration Options...................................3 
      2.1 IPv6-Compression-Protocol..................................3 
   3. Security Considerations........................................5 
   4. IANA Considerations............................................5 
   5. Acknowledgments................................................6 
   6. References.....................................................6 
      6.1 Normative References.......................................6 
      6.2 Informative References.....................................6 
   Editor's Address..................................................7 
   IPR Notice  ......................................................7 
   Copyright Notice and Disclaimer...................................8 
1. Introduction 
      PPP [1] has three main components: 
      1) A method for encapsulating datagrams over serial links. 
      2) A Link Control Protocol (LCP) for establishing, configuring,  
         and testing the data-link connection. 
      3) A family of Network Control Protocols (NCPs) for establishing  
         and configuring different network-layer protocols. 
      In order to establish communications over a point-to-point link,  
      each end of the PPP link must first send LCP packets to  
      configure and test the data link.  After the link has been  
      established and optional facilities have been negotiated as  
      needed by the LCP, PPP must send NCP packets to choose and  
      configure one or more network-layer protocols.  Once each of the  
      chosen network-layer protocols has been configured, datagrams  
      from each network-layer protocol can be sent over the link. The 
      link will remain configured for communications until  
      explicit LCP or NCP packets close the link down, or until some  
      external event occurs (power failure at the other end, carrier  
      drop, etc.). 
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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
      In the IPv6 over PPP specification [2], the NCP, or IPV6CP, for  
      establishing and configuring IPv6 over PPP is defined. The 
      same specification defines the Interface Identifier parameter, 
      which can be used to generate link-local and global unique IPv6  
      addresses, for negotiation.  
      In this specification, the compression parameter for use in IPv6  
      datagram compression is defined. Together with RFC 5072 [2], this 
      document obsoletes RFC 2472 [13]. However, no protocol changes 
      have been introduced over RFC 2472.  
1.1 Specification of Requirements 
      In this document, several words are used to signify the  
      requirements of the specification. 
      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL  
      "OPTIONAL" in this document are to be interpreted as described  
      in [3]. 
2.  IPV6CP Configuration Options 
      IPV6CP Configuration Options allow negotiation of desirable IPv6 
      parameters.  IPV6CP uses the same Configuration Option format as 
      defined for LCP [1] but with a separate set of Options.  If a  
      Configuration Option is not included in a Configure-Request  
      packet, the default value for that Configuration Option is  
      The only IPV6CP option defined in this document is the IPv6- 
      Compression-Protocol.  The Type field for this IPV6CP Option is as 
            2 IPv6-Compression-Protocol 
      Note that the up-to-date values of the IPV6CP Option Type field 
      are specified in the on-line database of "Assigned Numbers" 
      maintained at IANA [7].   
2.1 IPv6-Compression-Protocol 
      This Configuration Option provides a way to negotiate the use of a 
      specific IPv6 packet compression protocol.  The  
      IPv6-Compression-Protocol Configuration Option is used to indicate 
      the ability to receive compressed packets.  Each end of the link 

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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
      MUST separately request this option if bi-directional compression 
      is desired.  By default, compression is not enabled.  
      IPv6 compression negotiated with this option is specific to IPv6 
      datagrams and is not to be confused with compression resulting 
      from a compression method negotiated via the PPP Compression 
      Control Protocol (CCP) [12], which potentially affects all 
      A summary of the IPv6-Compression-Protocol Configuration Option 
      format is shown below.  The fields are transmitted from left to 
      0                   1                   2                   3 
      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 
      |     Type      |    Length     |   IPv6-Compression-Protocol   | 
      |    Data ... 
          >= 4 
         The IPv6-Compression-Protocol field is two octets and indicates 
         the compression protocol desired.  Values for this field are 
         always the same as the PPP Data Link Layer Protocol field 
         values for that same compression protocol. 
         IPv6-Compression-Protocol field values have been assigned in 
         [14] for IPv6 Header Compression (004f), [4, 5] for IP Header 
         Compression (0061), and [6] for Robust Header compression 
         (ROHC) (0003). Other assignments can be made in documents that 
         define specific compression algorithms. 
         The Data field is zero or more octets and contains additional 
         data as determined by the particular compression protocol. 
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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
          No IPv6 compression protocol enabled. 
3. Security Considerations 
      Lack of proper link security, such as authentication, prior to 
      data transfers may enable man-in-the middle attacks  
      resulting in the loss of data integrity and confidentiality. The 
      mechanisms that are appropriate for ensuring PPP link security 
      are addressed below together with the reference to a generic 
      threat model. 
      The mechanisms that are appropriate for ensuring PPP link 
      Security are: 1) Access Control Lists that apply filters on 
      traffic received over the link for enforcing admission policy, 2)  
      an Authentication protocol that facilitates negotiations between 
      peers [8] to select an authentication method (e.g., MD5 [9]) for 
      validation of the peer, and 3) an Encryption control protocol 
      that facilitates negotiations between peers to select encryption 
      algorithms (or,  crypto-suites) to ensure data confidentiality 
      There are certain threats associated with peer interactions on a 
      PPP link even with one or more of the above security measures in 
      place. For instance, using the  MD5 authentication method [9] 
      exposes one to replay attacks, in which an attacker could 
      intercept and replay a station's identity and password hash to 
      get access to a network. The user of this specification is 
      advised to refer to [8], which presents a generic threat model, 
      for an understanding of the threats posed to the security of a 
      link. The reference [8] also gives a framework to specify 
      requirements for the selection of an authentication method for a 
      given application. 
4. IANA Considerations  
      There are no specific recommendations for the IANA on the 
      assignment of values for the Type field of the IPv6 datagram 
      compression option specified in section 2.1 of this document. The 
      current assignment is up-to-date at [7]. 
      No action is needed either for the assignment of the  
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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
      IPv6-Compression-Protocol values, as such values have already 
      been defined by other documents listed in the Section 2.1. Values  
      for this field  are always the same as the PPP Data Link Layer  
      field values for that same compression protocol. As a result,  
      future allocation of these values is governed by RFC 3818 [11]  
      that requires IETF consensus process.  
5. Acknowledgments 
      The editor is grateful to Jari Arkko for the direction provided on 
      this draft and James Carlson for helpful suggestions. 
      Acknowledgements are also due to D. Haskins and E. Allen for the 
      specification work done in RFC 2023 and RFC 2472. 
6. References 
6.1 Normative References 
   [1] Simpson, W., "The Point-to-Point Protocol", STD 51, RFC 1661,  
       July 1994. 
   [2] Allen, E., Haskin, D., and, S. Varada, Ed., "IPv6 over PPP",  
       RFC 5072, September 2007. 
   [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement 
       Levels", BCP 14, RFC 2119, March 1997. 
   [4] Degermark M., B. Nordgren, and S. Pink, "IP Header Compression",   
       RFC 2507, February 1999. 
   [5] Koren T., S. Casner, and C. Bormann, "IP Header Compression Over 
       PPP", RFC 3544, July 2003. 
   [6] Bormann C., "Robust Header Compression (ROHC) over PPP", RFC  
       3241, April 2002. 
6.2 Informative References 
   [7] IANA, "Assigned Numbers", 
   [8] Aboba, R., Blunk, L., Vollbrecht, J., Carlson, J., and  
       H. Levkowetz,Ed., "Extensible Authentication Protocol", RFC 
       3748, June 2004. 

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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
   [9] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April  
   [10] Meyer, G., "The PPP Encryption Control Protocol (ECP)", RFC  
        1968, June 1996. 
   [11] Schryver, V., "IANA Considerations for the Point-to-Point  
        Protocol (PPP)", RFC 3818, June 2004. 
   [12] Rand, D., "The PPP Compression Control Protocol(CCP)", RFC 1962, 
        June 1996. 
   [13] Haskin D., and E. Allen, "IP Version 6 over PPP", RFC 2472, 
        December 1998. 
   [14] Haskin D., and E. Allen, "IP Version 6 over PPP", RFC 2023, 
        October 1996. 
Editor's Address 
      Srihari Varada 
      TranSwitch Corporation 
      3 Enterprise Dr. 
      Shelton, CT 06484. US. 
      Phone: +1 203 929 8810 
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              draft-ietf-ipv6-compression-nego-v2-02.txt February 2008 
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      This document and the information contained herein are provided 

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