Re: Re: CARD: Storing sequence numbers in ARs' CAR table?

On Tue, 14 Oct 2003, Eunsoo Shim wrote:

> Henrik and Marco,
>
> My comments are inline.
>
> > There is a similar problem is in the MN-AR protocol, with the ordering of
> > solicited and unsolicited replies. A new field in the MN-AR CARD message
> > header is _probably_ needed for sequence number, if strict ordering is a
> > requirement.
> >
> [eunsoo] There is already the sequence number field in the headers of CARD
> Request and Reply. Do you suggest any other field?

Actually the problem in MN was more complex than I had thought: MN can get
unsolicited CARD replies from multiple ARs and the information in ARs
about CARs is not synchronized. It seems that a per-CAR sequence number /
timestamp is needed in AR-MN reply for ordering to work.

A potential solution is to include the original sequence number from the
AR-AR CARD reply message header (not reply option) in some field for each
CAR, e.g. in the capability container suboption, in the MN-AR CARD reply.
Provided that the CAR increases the sequence number for every AR-AR CARD
message it sends, this should work. The sequence number handling might
need to work with wrap around, though.

Henrik