Re: [manet] packetbb update idea

[Henning Rogge <[e-mail]>]

On Mon, Jul 3, 2017 at 7:29 PM, Justin Dean <[e-mail]> wrote:
> So while trying to encode some information using packetbb for the elastic
> multicast stuff we have been working on I've run into a short coming.
> RFC5444 allows one to efficiently encode information about addresses and
> even pairs of addresses (as long as one of those addresses is the Oaddr)
> with the TLV structure and the address block.  It does not allow for easy
> encoding about pairs of addresses of which neither is the Oaddr.  After some
> thinking on it I think most of what I'd like to be able to do could be
> solved by using the RESERVED tlv flag bit number 6 to indicate inclusion of
> a single index field <index-opt> which would specify a single address in the
> address block.

You mean for things like source-specific routing (having a source- and
destination prefix for an attached network)?

I remember I did a rough sketch for this (I have implemented in my
Olsrd2-Implementation) and I was forced to put one of the addresses
uncompressed into a data TLV.

> So the tlv definition would change from
> <tlv> := <tlv-type>
>
>                 <tlv-flags>
>                 <tlv-type-ext>?
>                 (<index-start><index-stop>?)?
>                 (<length><value>?)?
>
> to
>
> <tlv> := <tlv-type>
>                 <tlv-flags>
>                 <tlv-type-ext>?
>
>                 <index-opt>?
>                 (<index-start><index-stop>?)?
>                 (<length><value>?)?
>
>
> This would allow one to specify information about pairs of addresses in a
> compact way.  In the case of elastic multicast source/destination flow
> pairs. Thoughts welcome.

IF (not sure it is worth) we add something to RFC5444, I would also
like to suggest an option in the address block TLVs to refer to the
originator address as the prefix/postfix part.

Henning