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Versions: 00 01 02 03 RFC 6345

Network Working Group                                           P. Duffy
Internet-Draft                                                     Cisco
Intended status: Standards Track                          S. Chakrabarti
Expires: March 25, 2011                                      IP Infusion
                                                               R. Cragie
                                                                    PG&E
                                                           Y. Ohba (Ed.)
                                                                 Toshiba
                                                                A. Yegin
                                                                 Samsung
                                                      September 21, 2010


  Protocol for Carrying Authentication for Network Access (PANA) Relay
                                Element
                        draft-ohba-pana-relay-00

Abstract

   This document specifies PANA (Protocol for carrying Authentication
   for Network Access) Relay Element functionality which enables PANA
   messaging between a PaC (PANA Client) and a PAA (PANA Authentication
   Agent) where the two nodes cannot reach each other by means of
   regular IP routing.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 25, 2011.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal



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   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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Specification of Requirements . . . . . . . . . . . . . . . 3
   2.  PANA Relay Element  . . . . . . . . . . . . . . . . . . . . . . 3
   3.  PANA messages for Relay Operation . . . . . . . . . . . . . . . 5
     3.1.  PANA-Relay  . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  PANA AVPs for Relay Operation . . . . . . . . . . . . . . . . . 6
     4.1.  PaC-Information AVP . . . . . . . . . . . . . . . . . . . . 6
     4.2.  Relayed-PDU AVP . . . . . . . . . . . . . . . . . . . . . . 6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8
























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1.  Introduction

   PANA (Protocol for carrying Authentication for Network Access)
   [RFC5191] is a UDP-based protocol to perform EAP authentication
   between a PaC (PANA Client) and a PAA (PANA Authentication Agent).

   This document specifies PANA Relay Element (PRE) functionality which
   enables PANA messaging between a PaC and a PAA where the two nodes
   cannot reach each other by means of regular IP routing.  For example,
   in ZigBee IP architecture (Editor's Note: a reference to ZigBee IP
   specification is to be added here when it is under public review), a
   joining-node (PaC) can only use a link-local IPv6 address to
   communicate with a parent router prior to PANA authentication.  The
   PAA resides in a 6LBR (6LowPAN Border Router) [I-D.ietf-6lowpan-nd]
   which is often multiple IP hops away from the PaC.  The PRE
   implemented on the parent router is used for relaying PANA PDUs
   between the PaC and the PAA in this scenario.

1.1.  Specification of Requirements

   In this document, several words are used to signify the requirements
   of the specification.  These words are often capitalized.  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 [RFC2119].


2.  PANA Relay Element

   The PANA Relay Element (PRE) is a node that is located between the
   PaC and the PAA.  It is responsible for relaying the PANA PDUs
   between the PaC and the PAA.  The PRE does not need to maintain per-
   PaC state.  From the PaC's perspective the PRE appears as the PAA.
   Normal IP routing is performed between the PRE and the PAA.  It is
   assumed that the PRE's IP address that is reachable from the PaC is
   known to the PaC prior to PANA authentication by some means that is
   not specified in this document.  It is also assumed that the PAA's IP
   address that is reachable from the PRE is known to the PRE by some
   means that is not specified in this document.

   The PRE and the PAA supporting the relay operation function as
   follows.

   The relay operation requires that a PANA session is initiated by the
   PaC, i.e., the first message that the PRE relays for any PANA session
   is a PCI (PANA-Client-Initiation) message.

   When the PRE receives a PANA PDU from the PaC, it creates a PANA-



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   Relay (PRY) message containing a Relayed-PDU AVP and a PaC-
   Information AVP.  The Relayed-PDU AVP encapsulates the entire PANA
   PDU received from the PaC.  The PaC-Information AVP contains the
   PaC's IP address and UDP port number.  The PRY message is sent to the
   PAA.

   When the PAA receives the PRY, it retrieves the PaC-originated PANA
   PDU from the Relayed-PDU AVP and the PaC's IP address and UDP port
   number from the PaC-Information AVP.  The PaC-originated PANA PDU is
   processed in the same way as specified in RFC 5191, with the
   following exceptions:

   (a) The PaC's IP address and UDP port number are maintained in the
   PANA session attribute "IP address and UDP port number of the PaC".

   (b) The source IP address and UDP port number of the PRY is stored in
   a new PANA session attribute "IP address and UDP port number of the
   PRE".  A PANA session is referred to as a relayed PANA session if
   this attribute has a non-null value.

   When the PAA originates a PANA PDU for a relayed PANA session, it
   sends a PRY message to the PRE's IP address and UDP port number.  The
   PRY message includes a Relayed-PDU AVP containing the PAA-originated
   PANA PDU and also includes a PaC-Information AVP containing the PaC's
   IP address and UDP port number.

   When the PRE receives the PRY message, it retrieves the PAA-
   originated PANA PDU from the Relayed-PDU and the PaC's IP address and
   UDP port number from and PaC-Information AVPs.  The PAA-originated
   PANA PDU is sent to the PaC's IP address and UDP port number.

   The Session Identifier and Sequence Number of a PRY message are set
   to zero.  A PRY message is never retransmitted by the PRE or the PAA.
   The PRE and PAA do not advance its incoming or outgoing sequence
   numbers for request when transmitting or receiving a PRY message.
   Note that the PANA message carried in a Relayed-PDU may be
   retransmitted by the PaC or PAA, leading to transmission of another
   PRY carrying the same Relayed-PDU.

   If direct IP routing becomes available (e.g., after the successful
   PANA authentication as in the case of Zigbee IP), the PaC may choose
   to directly communicate with the PAA without use of the relay
   operation.  The IP address update procedure defined in [RFC5191] may
   be performed to switch to non-relay operation.

   Figure 1 is an example message flow with a PRE.





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 PaC(IP1:p1)  (IP2a:716)PRE(IP2b:p2)           (IP3)PAA  srcIP:port->dstIP:port
 --------     ------------------------         -------   ----------------------
1.  ----PCI--->                                         IP1:p1  -> IP2a:716

2.              ----PRY[P{IP1:p1},R{PCI}]--->           IP2b:p2 -> IP3:716

3.              <---PRY[P{IP1:p1},R{PAR}]----           IP3:716 -> IP2b:p2

4. <----PAR---                                          IP2a:716 -> IP1:p1

5.  ----PAN--->                                         IP1:p1  -> IP2a:716

6.              ----PRY[P{IP1:p1},R{PAN}]--->           IP2b:p2 -> IP3:716

7.              <---PRY[P{IP1:p1},R{PAR}]----           IP3:716 -> IP2b:p2

8. <----PAR---                                          IP2a:716 -> IP1:p1

9.  ----PAN--->                                         IP1:p1  -> IP2a:716

10.             ----PRY[P{IP1:p1},R{PAN}]--->           IP2b:p2 -> IP3:716

   IP1 is the IP address of PaC.

   IP2a and IP2b are the IP addresses of PRE. The two IP address
   may be the same.

   IP3 is the IP address of PAA.

   P: PaC-Information AVP
   R: Relayed-PDU AVP


               Figure 1: Example Call Message for PANA Relay


3.  PANA messages for Relay Operation

3.1.  PANA-Relay

   The PANA-Relay (PRY) message is sent by the PRE to the PAA or by the
   PAA to the PRE.  It contains one PaC-Information AVP and one Relayed-
   PDU AVP.  The PRY message MAY carry other AVPs.

   In a PRE-originated PFY message, the PaC-Information AVP contains an
   IP address and the UDP port number of the PANA PDU that was
   originated by the PaC and is contained in the Relayed-PDU AVP.




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   In a PAA-originated PRY message, the information in the PaC-
   Information AVP MUST be copied from the "IP address and UDP port
   number of the PaC" attribute of the associated PANA session
   [RFC5191].

   The Session Identifier and Sequence Number field of any PRY message
   MUST be set to zero.  A PRY message MUST NOT be retransmitted by the
   PRE or the PAA.  The PRE and PAA MUST NOT advance its incoming or
   outgoing sequence numbers for request when transmitting or receiving
   a PRY message.

      PANA-Relay ::= < PANA-Header: TBD>
                     { PaC-Information }
                     { Relayed-PANA-PDU }
                    *[ AVP ]



4.  PANA AVPs for Relay Operation

4.1.  PaC-Information AVP

   The PaC-Information AVP (AVP Code TBD) is of type OctetString and
   contains an IP address (16-octet for IPv6 address and 4-octet for
   IPv4 address) followed by 2-octet UDP port number of the PaC, both
   encoded in network-byte order.

4.2.  Relayed-PDU AVP

   The Relayed-PANA-PDU (AVP Code TBD) is of type OctetString and
   contains a relayed PANA PDU.


5.  Security Considerations

   Since the PRE does not maintain per-PaC state, the PRE is robust
   against resource consumption DoS (Deniable of Service) attack.  The
   security properties of the PaC and PAA remain the same as [RFC5191].

   If cryptographic integrity protection is needed for PRY messages, it
   MUST be provided by either a PANA layer protection mechanism (TBD) or
   a lower-layer protection mechanism using, e.g., IPsec.

   (Editor's note: PANA-layer integrity protection for PRY messages
   needs more investigation considering that PRY messages are not
   retransmitted and therefore sequence numbers are not used for them,
   whereas sequence numbers are needed for protecting other PANA
   messages using a PANA SA.  As a result, PANA-layer integrity



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   protection for PRY messages may require a different mechanism from
   that is defined in [RFC5191].  The authors will continue to
   investigate candidate PANA-layer integrity protection mechanisms for
   PRY messages and define one in a future revision of the document.)


6.  IANA Considerations

   As described in Sections Section 3 and Section 4, and following the
   new IANA allocation policy on PANA messages [RFC5872], one Message
   Type and two PANA AVP Codes need to be assigned.

   o  One standard Message Type for PANA-Relay (PRY) message.

   o  One standard AVP Code for PaC-Information AVP.

   o  One standard AVP Code for Relayed-PDU AVP.


7.  Acknowledgments

   The authors would like to thank Vlad Gherghisan for valuable
   comments.


8.  References

8.1.  Normative References

   [RFC5191]  Forsberg, D., Ohba, Y., Patil, B., Tschofenig, H., and A.
              Yegin, "Protocol for Carrying Authentication for Network
              Access (PANA)", RFC 5191, May 2008.

   [RFC5872]  Arkko, J. and A. Yegin, "IANA Rules for the Protocol for
              Carrying Authentication for Network Access (PANA)",
              RFC 5872, May 2010.

8.2.  Informative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [I-D.ietf-6lowpan-nd]
              Shelby, Z., Chakrabarti, S., and E. Nordmark, "Neighbor
              Discovery Optimization for Low-power and Lossy Networks",



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              draft-ietf-6lowpan-nd-13 (work in progress),
              September 2010.


Authors' Addresses

   Paul Duffy
   Cisco Systems
   200 Beaver Brook Road
   Boxborough, MA 01719
   USA

   Email: paduffy@cisco.com


   Samita Chakrabarti
   IP Infusion
   1188 Arquest Street
   Sunnyvale, CA
   USA

   Email: samitac@ipinfusion.com


   Robert Cragie
   Pacific Gas & Electric
   Gridmerge Ltd., 89 Greenfield Crescent
   Wakefield, WF4 4WA
   UK

   Email: robert.cragie@gridmerge.com


   Yoshihiro Ohba
   Toshiba Corporate Research and Development Center
   1 Komukai-Toshiba-cho
   Saiwai-ku, Kawasaki, Kanagawa  212-8582
   Japan

   Phone: +81 44 549 2127
   Email: yoshihiro.ohba@toshiba.co.jp










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   Alper Yegin
   Samsung
   Istanbul
   Turkey

   Email: alper.yegin@yegin.org













































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