Re: [ippm] v6 option types for IOAM data fields

["C. M. Heard" <[e-mail]>]

On Thu, 25 Oct 2018 15:06:57 +0000 Frank Brockners (fbrockne) wrote:
> Quick heads up: In the 6MAN meeting in BKK, we’ll review
> draft-ioametal-ippm-6man-ioam-ipv6-options-01 – which requests 2 option
> types from the DO/HbyH options sub-registry.
>
> While the bulk of the IOAM work is progressed in the IPPM WG, we’d greatly
> appreciate your feedback on draft-ioametal-ippm-6man-ioam-ipv6-options-01,
> which defines how IOAM data fields are carried using v6 extension headers.
> Cc’ing the IPPM WG as well, to keep everyone on the same page.

I have two brief comments on this work.

First, I see that the Incremental Tracing Option changes length in transit.
It is not appropriate for it to be carried in an IPv6 option intended for
use on the open Internet, for exactly the same reason that insertion of
extension headers by intermediate nodes is not allowed on the open Internet.

Second, I see that two IPv6 option code points are requested, one with the
"chg" flag set, the other with the "chg" flag clear. While there is no harm
in this, it is not strictly necessary; the only real purpose of this flag
is to determine whether the option data is or is not included in the
Authentication Header Integrity Check Value computation.

Mike Heard