At 5:39 PM +0900 5/24/00, [EMAIL PROTECTED] wrote:
>when a node A received packet from mobile node B:
>packet will carry home address of B in home address option (destination
>options header, and care-of address in IPv6 source
>- which address should getpeername() return? home address, or care-of?
> home address sounds like a good default pick, however, some apps
> may need to look at care-of.
Itojun,
On the correspondent node, getpeername() should return the home address
of the mobile node. This is so most apps can be oblivious to the mobility
of the node to which they are speaking.
Can you give some examples of why an app on the correspondent node would
want or need to know the current care-of address of its peer?
>- which address should recvfrom() return?
> ditto.
The home address.
>- can we get home address option in IPV6_RECVDSTOPTS?
> it seems like so. it will have home address of B, not care-of.
If you really need to receive both addresses for some reason, the care-of
address is the one that should be obtainable only via IPV6_RECVDSTOPTS.
Logically, the IP layer in the correspondent host should swap the received
home address and care-of address before passing the packet to an upper
layer.
>when a mobile node A sends packet to a node B:
>A may want to control the use of mobile-ip6. examples: (1) if A would like
>to talk to ubiquitous services like DNS, A may want to use care-of address,
>not the home address. (2) IKE (to establish key for mobile-ip6) requires it.
>- how can we avoid use of home address? 1-bit flag in setsockopt?
This is just another example of the source-address selection problem (as
discussed in Rich's draft). When initiating communication, the mobile
host must select one of its valid addresses to use as source address.
The default behavior, if the application or user doesn't care, would be
to use the home address (or one of the home addresses, if there are
more than one). But an application, such as the ones you mentioned,
can choose to use a different source address, i.e., the temporary
care-of address. We should already have whatever API function is needed
for the app to specify the source address, so no new flags ought to be
needed.
Steve
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