Re: [CARD Technical Issue] U flag and Unsolicited CARD

> Section 4.2.2 mentions that unsolicited broadcast is possible, why not
> multicast? For IPv4, this would require a multicast address,  but for IPv6
> it could be done to the All Nodes Multicast address on the link. There is
no
> broadcast in IPv6, so multicast will be required in that case anyway.
>
[eunsoo] Multicast is fine with me.

> The draft also contains no guidelines about unsolicited. What is the
default
> intermessage time on broadcast/multicast? What about the port number and
> TTL?
>
[eunsoo] Since it is the AR that sends the unsolicited CARD replies, the
transmission rate will depend on the configuration. We tried to avoid
recommending an arbitrary number as default values without base.

The same port number as the solicited CARD reply is used for the unsolicted
CARD reply.

What do you think would be the proper TTL for the unsolicited CARD reply? I
thought TTL 1 should be fine between MN-AR.

> Also, I'm not clear about why an unsolicited message needs to be marked.
How
> would a MN utilize the U flag? How would processing of a solicited v.s.
> unsolicited message differ?
>
>

For solicited CARD replies, the receiver needs to match the reply to the
request by the sequence number. For unsolicited replies, there is no
matching request and thus the receiver should be able to distinguish the
unsolicted replies from the solicited ones.

Eunsoo