Subject: Re: [mobile-ip] deregistration from foreign link

From: Samita Chakrabarti <[email-masked]>
Date: Wed, 22 Jan 2003 10:56:24 -0800 (PST)

> When a MN locates at a foreing link and sends a de-registration BU (the
> BU which lifetime set to zero), the MN must not use the Careof Keygen
> Token to calculate the authenticator according to the draft (section
> 9.5.1).
> 
> Since the MN is at the foreign link and uses CoA as the source address
> of the BU, MN should verify CoA of the BU as well as a normal BU.
> 
> any comments?
> 

It looks like a bug in the spec (from draft 19).  This item in section 9.5.1 
is valid  for only when COA=Home address. So, you are correct in saying that
both home keygen and care-of keygen need to be considered to calculate Kbm
when care-of-addr != home-addr of the BU.

Note, section 5.2.6 also confirms that:

   A Binding Update may also be used to delete a previously established
   binding by setting the care-of address equal to the home address
   (Section 6.1.7).  In this case, the care-of keygen token is not used.
   Instead, the binding management key is generated as follows:

    Kbm = SHA1(home keygen token)

 -Samita

> Section 9.5.1 said
>    o  If the Lifetime specified in the Binding Update is zero or the
>       specified care-of address matches the home address for the
>       binding, then this is a request to delete the mobile node's cached
>       binding.  In this case, the Binding Update MUST include a valid
>       home nonce index, and the care-of nonce index MUST be ignored by
>       the correspondent node.  The generation of the binding management
>       key depends then exclusively on the home keygen token (Section
>       5.2.5).  If the Home Registration (H) bit is set in the Binding
>       Update, the Binding Update is processed according to the procedure
>       specified in Section 10.3.2; otherwise, it is processed according
>       to the procedure specified in Section 9.5.3.
> 
> regards,
> ryuji
>

---

From: Vladislav Yasevich <[email-masked]>
Date: Wed, 22 Jan 2003 15:23:07 -0500

No, this is not a bug in the spec.

See issue 98 for the discussion (particularly the later discussion
by Gabriel).

-vlad

-- 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Vladislav Yasevich		Tru64 UNIX - IPv6 Project Lead
Hewlett Packard 		Tel: (603) 884-1079
Nashua, NH 03062		ZKO3-3/T07