Re: [Ioam] Internal WG Review: In-situ OAM (ioam)

Stephen:

Hi!

I think tricky, but important.  I’m cc’ing the list to get the answers there.

To your second question.  Yes, there clearly is an expectation on the outcome, if IPv6 is used as an encapsulating protocol.  But that is not the only application.

Thanks!

Alvaro.

On 2/9/17, 3:15 PM, "iesg on behalf of Stephen Farrell" <iesg-bounces@ietf.org<mailto:iesg-bounces@ietf.org> on behalf of stephen.farrell@cs.tcd.ie<mailto:stephen.farrell@cs.tcd.ie>> wrote:

Hiya,

I have two possibly tricky questions about this:

1) I'm sure there are good things one can do with such
marking, but it is very unclear to me how this proposal
doesn't also fall afoul of all the privacy downsides of
the SPUD/PLUS proposal. My understanding of those privacy
downsides was that any generic/extensible marking scheme
(whether of packets or transport connections/flows) could
easily be abused in many privacy unfriendly ways. Note
that I'm not claiming there is IETF consensus on that
but I do claim it was a significant issue for SPUD/PLUS
and would like to know why (and hope) it is not an issue
here. Can someone help me understand what's different here
so we avoid that same kind of mega-debate?

2) There is an ongoing and seemingly very hard to resolve
discussion [1] on ietf@ietf.org<mailto:ietf@ietf.org> in which a draft related to
this proposal has been quoted [2] as evidence on one side
of the argument. I'm not clear that we should go ahead with
this charter before we have established IETF consensus
one way or another about what we think about [1] (by which
I specifically mean the issue of headers being processed
away from the endpoints). If I'm right that these are
related (and it's possible I'm entirely wrong;-) then I
guess depending on the outcome of [1] that'd either mean
a short delay for this, or else a need for some major
change and that risk would seem to me to justify not
forging ahead with this just yet. So the question is:
am I right that this proposal assumes one outcome of
the discussion about header processing in [1]?

Cheers,
S.

PS: I'm fine to ask these two questions in a ballot if that's
better. But at the moment that'd likely be a BLOCK ballot
so I wanted to check first if I'm off base, as happens now
and then:-)

[1] https://www.ietf.org/mail-archive/web/ietf/current/msg100960.html
[2] https://www.ietf.org/mail-archive/web/ietf/current/msg101012.html

On 08/02/17 18:32, IETF Secretariat wrote:
A new IETF WG is being considered in the IETF. The draft charter for this
WG is provided below for your review and comment.
Review time is one week.
The IETF Secretariat
In-situ OAM (ioam)
-----------------------------------------------------------------------
Current status: Proposed WG
Chairs:
   TBD
Assigned Area Director:
   Alvaro Retana <aretana@cisco.com<mailto:aretana@cisco.com>>
Routing Area Directors:
   Alia Atlas <akatlas@gmail.com<mailto:akatlas@gmail.com>>
   Alvaro Retana <aretana@cisco.com<mailto:aretana@cisco.com>>
   Deborah Brungard <db3546@att.com<mailto:db3546@att.com>>

Mailing list:
   Address: ioam@ietf.org<mailto:ioam@ietf.org>
   To subscribe: https://www.ietf.org/mailman/listinfo/ioam
   Archive: https://mailarchive.ietf.org/arch/browse/ioam/
Charter: https://datatracker.ietf.org/doc/charter-ietf-ioam/
In-situ OAM provides real-time telemetry of individual data packets and
flows. It is based on telemetry information which is embedded within live
data packets. The IOAM WG intends to define data formats and associated
procedures for in-situ OAM, including mechanisms for capturing path and
path-traversal related information as well as procedures to employ,
configure, trigger, and export the embedded telemetry information.

The IOAM WG will define the following in-situ OAM components:

* Data-records for in-situ OAM to cover path-tracing and path
verification information (node-ids, ingress/egress interfaces),
timestamps, transit-delay, transit jitter, sequence numbers,
application-defined metadata. In-situ OAM data-records are defined using
an in-situ OAM namespace. It should be possible to control the
information that gets recorded in data-records.
* Procedures to add, update, remove, retrieve and export data-records for
in-situ OAM to live traffic and active probing.  In case of live traffic
a classifier to select subset of live traffic for addition, update,
removal and retrieval of in-situ OAM data-records. In case of active
probing procedure to return the in-situ OAM data records to the source of
the probe.
*  Scope of in-situ OAM operation. In-Situ OAM operations are defined for
a specific operational domain. In-situ OAM data-records are added and
removed at domain boundaries and updated by nodes within the in-situ OAM
domain. Procedure to deal with various challenges in packet forwarding
and error handling such as ECMP processing, path MTU and ICMP message
handling when in-situ OAM is enabled in an in-situ OAM domain.
*  Data-records for in-situ OAM are to be defined in a way that makes
them independent from the transport protocol used. Data-records for
in-situ OAM will need to be embedded into transport protocols such as
IPv4, IPv6, VXLAN-GPE, LISP, NSH, SRv6, Geneve.
* Procedures and data-records optimized for software dataplane and
hardware dataplane implementations of in-situ OAM.
* In-situ OAM to support layering. If several transport protocols (e.g.
in case of tunneling) are stacked on top of each other, in-situ OAM
data-records could be present in every transport protocol layer.
* Management and control of role of nodes for in-situ OAM operation,
dynamic control of in-situ OAM data collected in the data records, data
export optimization.

The IOAM working group intends to work on and publish:
* Definition of the data-type formats used in in-situ OAM and namespaces
for in-situ OAM.
* Definition of procedures that in-situ OAM enabled nodes will perform on
data traffic that carries in-situ OAM information (e.g., introducing,
removing, processing, modifying, and exporting the telemetry information
from the associated data packets).
* Configuration and operational data models for controlling in-situ OAM
data and operations.
In-situ OAM data records could be embedded into a variety of transports.
The transports are expected to be defined in the respective working
group(s) like NVO3, SFC, 6man, MPLS etc in consultation with the IOAM
working group documents. IOAM WG exclusively focuses on mechanisms which
piggyback OAM-related metadata onto en-route traffic for OAM purposes.
Other ongoing OAM-related efforts in working groups(s) such as MPLS and
IPPM that do not piggyback information onto the live user data traffic
are out of scope of the IOAM WG.

Milestones

April 2018 - submit data format and associated procedures document to
IESG.
March 2018 - WGLC for data format and associated procedures document.
April 2017 - working group adoption of data format and associated
procedures document
Milestones: