Subject: [nemo] Problems in rfc

From: Antonio de la Oliva Delgado <[email-masked]>
Date: Tue, 16 Nov 2004 18:18:54 +0100

Hi all,

We are implementing the NEMO Basic Support Protocol within the framework
of the DAIDALOS European project. When dealing with the BU message
format part of the I-D, we have found that, IMHO, there is some text
that is not completely clear for a developer. 
The section 4.1 says:

   "A new flag (R) is included in the Binding Update to indicate to the
   Home Agent if the Binding Update is coming from a Mobile Router
   and not from a mobile node.  The rest of the Binding Update format
   remains the same as defined in [1].

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                       |          Sequence #           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|H|L|K|M|R|      Reserved     |           Lifetime            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       .                                                               .
       .                        Mobility options                       .
       .                                                               .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"

Reference [1] (RFC3775) says the following about the BU message format:

   "The Binding Update uses the MH Type value 5.  When this value is
   indicated in the MH Type field, the format of the Message Data field
   in the Mobility Header is as follows:

                                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                       |          Sequence #           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|H|L|K|        Reserved       |           Lifetime            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       .                                                               .
       .                        Mobility options                       .
       .                                                               .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"

The bit M is not defined in RFC3775 or in the Nemo draft, but in the
HMIPv6 I-D (draft-ietf-mipshop-hmipv6-03.txt).

Therefore, I would suggest to reflect in the current text of the NEMO
Basic Support protocol, some reference about the HMIPv6 specification.

Kind Regards,
Antonio de la Oliva
Carlos J.