Re: 6man w.g. last call for <draft-ietf-6man-segment-routing-header-11.txt>

[Brian E Carpenter <[e-mail]>]

On 17/04/2018 11:23, Voyer, Daniel wrote:
...
>     2) In order to reduce the degree to which SRv6 extends the IPv6 Addressing Architecture, the document should represent service-based instructions as Destination Options
> [DV] This seems to be another attempt to tell an operator what they may use an IPv6 address for.  You are or course free to put whatever you wish in a destination option and parse its TLVs.  As any other implementation is free to use IPv6 address they own for whatever purpose they choose.    

As a point of information, IPv6 prefixes are not owned. They were originally delegated
to IANA under the terms of RFC1881 (an IAB document): "Delegation of address space
by the IANA is not irrevocable." This doesn't in itself directly affect your point,
but IPv6 delegations are not transfers of ownership; they are more like leases.

As to whether address bits should be used for purposes other than addressing,
that's a whole other discussion. Personally I suggest keeping that discussion
out of the present draft, which means not duplicating material from
spring-srv6-network-programming. At the moment there seems to be quite a bit
of overlapping text, and that will cause problems later. I don't see
that any of that discussion is needed in the normative definition of
the SRH. Actually it makes it confusing for the reader - when I look again
at the description of the End or End.X functions, they really tie the
reader up in broader aspects of segment routing rather than help to
clarify the meaning of the header considered on its own. You could define
the meaning of "segments left" without mentioning the SRH Functions
concept at all.

(I may be slightly disagreeing with Ron here, but I think we should
keep the 6man document as simple as possible, with the details coming
along later in spring-srv6-network-programming.)

    Brian