Re: [mobile-ip] Last Call: Mobility Support in IPv6 to Proposed Standard

[Erik Nordmark <Erik.Nordmark@sun.com>]

> * Route BAs via home agent: I think we need them to go
>    directly to the sender. Otherwise, after a movement,
>    it is very hard to see an error response. Or?

Also, to avoid reflection attacks it makes sense sending the BA to the
IP source address in the BU.

> * Retransmissions and mandatory BAs -- I think you are
>    right, both A=1 and mandatory BA case needs to have
>    retransmission rules and state.

That looks odd - typically protocols only need the "request" retranmitted.
Having retransmit timers on a "reply" might cause confusion when the "request"
is also being retransmitted.
In this particular case, for A=1 the BU will be retransmitted when the
MN doesn't receive a BA.
For error BAs presumably what caused the BU to be sent (e.g. receiving
packets tunneled from the HA) will sooner or later result in a new BU
(because the first BU was not accepted) which will cause the same error
i.e. a new BA.
Isn't that sufficient?

  Erik