Re: confusion in mipv6 I-D?

well, these statements are used in differnt contexts.


Frank Quick wrote:

> In 11.7.1, page 131:
>
> "The care-of address for the binding MUST be used as the Source 
> Address in the packet's IPv6 header, unless an Alternate Care-of 
> Address mobility option is included in the Binding Update."

the above sentence is trying to say that the address (CoA) to which the 
MN is binding
the home address MUST be in the source address or in the alt CoA 
mobility option.

>
> In same section, page 132:
>
> "The mobile node MUST use its home address - either in the Home 
> Address destination option or in   the Source Address field of the 
> IPv6 header - in Binding Updates sent to the home agent." 

this sentence is trying to say the Home Address MUST be either in the 
Home Adress
option or in the source address. the source address is set to the Home 
Address when
the MN sends a Binding Update (for example for deregistration) from the 
home link.
ingress filtering in the visited link will always prevent the MN from 
setting the
source address to home address when the MN is on a visited link. the MN 
can use
home address as source address only in the home link.

>
>
> I would recommend some additional explanation, 


see section 6.1.7

>   The care-of address is specified either by the Source Address field
>   in the IPv6 header or by the Alternate Care-of Address option, if
>   present.  The care-of address MUST be a unicast routable address.
>   IPv6 Source Address MUST be a topologically correct source address.
>   Binding Updates for a care-of address which is not a unicast routable
>   address MUST be silently discarded.  Similarly, the Binding Update
>   MUST be silently discarded if the care-of address appears as a home
>   address in an existing Binding Cache entry, with its current location
>   creating a circular reference back to the home address specified in
>   the Binding Update (possibly through additional entries).
>
>   The deletion of a binding can be indicated by setting the Lifetime
>   field to 0 and by setting the care-of address equal to the home
>   address.  In deletion, the generation of the binding management key
>   depends exclusively on the home keygen token, as explained in Section
>   5.2.5.  (Note that while the senders are required to set both the
>   Lifetime field to 0 and the care-of address equal to the home
>   address, Section 9.5.1 rules for receivers are more liberal, and
>   interpret either condition as a deletion.)
>

and section 9.5.1

>   The specified care-of address MUST be determined as follows:
>
>   o  If the Alternate Care-of Address option is present, the care-of
>      address is the address in that option.
>
>   o  Otherwise, the care-of address is the Source Address field in the
>      packet's IPv6 header.
>
>   The home address for the binding MUST be determined as follows:
>
>   o  If the Home Address destination option is present, the home
>      address is the address in that option.
>
>   o  Otherwise, the home address is the Source Address field in the
>      packet's IPv6 header.
>  
>

Vijay