Subject: [Pana] issue 91 (proposed text)

From: Yoshihiro Ohba <[email-masked]>
Date: Thu, 24 Jun 2004 14:52:36 -0700

This is a proposed text for PANA issue 91
(http://danforsberg.info:8080/pana-issues/issue91):

[1] Add the following paragraph in section 3:

"
In addition, PANA defines the following two types of re-authentication
procedures that are performed while an established PANA session
exists.

1. Re-authentication based on EAP

2. Re-authentication based on PANA-Reauth exchange

The former type of re-authentication is used mainly for extending
authorization lifetime or for updating the cryptographic keying
material of a PANA SA.  The latter type of re-authentication is used
mainly for maintaining the presence of the communicating peers each
other so that the established PANA session can be terminated as soon
as the presence of the peer is lost.  
"

[2] Add the following section:

"
3.1  Illustration of a Complete Message Sequence

   A complete PANA message sequence is illustrated in Figure 2.  The
   example assumes the following scenario:

   o  The PaC initiates the discovery and initial handshake phase by
      multicasting a PANA-PAA-Discover message.  The PAA responds with
      a PANA-Start-Request message with a cookie to be stateless in
      the discovery and initial handshake phase.  At the end of the
       the discovery and initial handshake phase, the PaC sends a
      PANA-Start-Answer message with a cookie in response to the
      PANA-Start-Request.

   o  An EAP authentication method with a single round trip is used in
      the authentication phase.  A AAA-Key is derived from the EAP
      method and used for establishing a PANA SA.

   o  At the end of the authentication phase, the PAA sends a
      PANA-Bind-Request message and the PaC responds with a
      PANA-Bind-Answer message.  These messages contains a MAC AVP and
      a Key-Id AVP, as well as other AVPs for which usages are
      explained in Section 4, to securely establish a PANA session
      with a PANA SA.

   o  After the PANA SA is established, all messages are integrity and
      replay protected with MAC AVPs.

   o  After the PANA SA is established, Re-authentication based on
      PANA-Reauth exchange is performed.

   o  The PaC initiates termination of the PANA session by sending a
      PANA-Termination-Request message.

   o  Sequence numbers in PANA headers are not shown.

      PaC      PAA  Message(tseq,rseq)[AVPs]
      -----------------------------------------------------
      // Discovery and initial handshake phase
         ----->     PANA-PAA-Discover 
         <-----     PANA-Start-Request[Cookie]
         ----->     PANA-Start-Request-Answer[Cookie]

      // Authentication phase
         <-----     PANA-Auth-Request[EAP]
         ----->     PANA-Auth-Answer[EAP]
         <-----     PANA-Auth-Request[EAP]
         ----->     PANA-Auth-Answer[EAP]
         <-----     PANA-Bind-Request[EAP{Success}, Device-Id, Key-Id,
                         Lifetime, Protection-Cap., PPAC, MAC]
         ----->     PANA-Bind-Answer[Device-Id, Key-Id, PPAC, MAC]

      // Re-authentication
         <-----     PANA-Reauth-Request[MAC]
         ----->     PANA-Reauth-Answer[MAC]

      // Termination phase
         ----->     PANA-Termination-Request[MAC]
         <-----     PANA-Termination-Answer[MAC]

                 Figure 2: A Complete Message Sequence
"

[3] Change Section 4.6 to:

"
4.6.  Example for NAP and ISP Separate Authentication

   A PANA message sequence where NAP and ISP separate authentication
   occurs is illustrated in Figure 9.  The example assumes the
   following scenario:

   o  The PaC multicasts PANA-PAA-Discover message

   o  The ISNs used by the PAA and the PaC are x and y, respectively.

   o  The PAA offers NAP and ISP separate authentication, as well as a
      choice of ISP from "ISP1" and "ISP2".  The PaC accepts the offer
      from the PAA, with choosing "ISP1" as the ISP.

   o  An EAP sequence for NAP authentication and an EAP sequence for ISP
      authentication is performed in this order in authentication phase.

   o  An EAP authentication method with a single round trip is used in
      each EAP sequence.

   o  Two AAA-Keys are derived from the EAP authentication methods,
      i.e., AAA-Key1 and AAA-Key2.  The PANA_MAC_Key is first derived
      from the AAA-Key1 upon the completion of the first EAP, and then
      it is updated so that it is derived from both AAA-Key1 and
      AAA-Key2 upon the completion of the second EAP.

   o  After a PANA SA is established, all messages are integrity and
      replay protected with MAC AVPs.

   o  Re-authentication based on the PANA-Reauth exchange is performed.

   o  Re-authentication and termination phase are not shown.

      PaC      PAA  Message(tseq,rseq)[AVPs]
      -----------------------------------------------------
      // Discovery and initial handshake phase
         ----->    PANA-PAA-Discover (0,0)
         <-----     PANA-Start-Request (x,0)            // S-flag set
                    [Cookie, ISP-Information("ISP1"),
                     ISP-Information("ISP2"),
                     NAP-Information("MyNAP")]
         ----->     PANA-Start-Request-Answer (y,x)     // S-flag set
                    [Cookie, ISP-Information("ISP1")]   // PaC chooses "ISP1"

      // Authentication phase
         <-----     PANA-Auth-Request(x+1,y)[EAP]       // NAP authentication
                                                        // S- and N-flags set
         ----->     PANA-Auth-Answer(y+1,x+1)[EAP]      // S- and N-flags set
         <-----     PANA-Auth-Request(x+2,y+1)[EAP]     // S- and N-flags set
         ----->     PANA-Auth-Answer(y+2,x+2)[EAP]      // S- and N-flags set
         <-----     PANA-FirstAuth-End-Request(x+3,y+2) // S- and N-flags set
                      [EAP{Success}, Key-Id, MAC]
         ----->     PANA-FirstAuth-End-Answer(y+3,x+3)  // S- and N-flags set
                      [Key-Id, MAC]
         <-----     PANA-Auth-Request(x+3,y+4)[EAP, MAC]// ISP authentication
                                                        // S-flag set
         ----->     PANA-Auth-Answer(y+4,x+4)[EAP, MAC] // S-flag set
         <-----     PANA-Auth-Request(x+4,y+5)[EAP, MAC]// S-flag set
         ----->     PANA-Auth-Answer(y+5,x+5)[EAP, MAC] // S-flag set
         <-----     PANA-Bind-Request(x+5,y+6)          // S-flag set
                      [EAP{Success}, Device-Id, Key-Id,
                       Lifetime, Protection-Cap., PPAC, MAC]
         ----->     PANA-Bind-Answer(y+6,x+5)           // S-flag set
                      [Device-Id, Key-Id, PPAC, MAC]

     Figure 9: A Complete Message Sequence for NAP and ISP Separate
                            Authentications
"

Comments are appreciated.

Yoshihiro Ohba

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