Re: [mpls] Review of draft-ietf-mpls-residence-time-12

[Greg Mirsky <[e-mail]>]

Hi Les,
thank you for your thoughtful consideration and the most helpful
suggestion. I'll prepare update accordingly and share with you and the
IS-IS community.
And, as John expressed, sorry that missed to reach to IS-IS experts in the
first place.

Regards, Greg

On Thu, Jan 19, 2017 at 2:04 PM, John E Drake <[e-mail]> wrote:

> Les,
>
>
>
> Shall we go with a sub-TLV of TLV 22 and promise to never ever to do this
> again?
>
>
>
> Btw, I am extremely sorry that we didn’t engage with the IS-IS community
> and I don’t know why we didn’t.  As I said in an earlier email, we worked
> pretty extensively with Acee on the OSPF aspects and with Lou Berger on the
> RSVP-TE aspects and received a lot of useful feedback from both of them.
>
>
>
> Yours Irrespectively,
>
>
>
> John
>
>
>
> *From:* Les Ginsberg (ginsberg) [mailto:[e-mail]]
> *Sent:* Thursday, January 19, 2017 4:55 PM
>
> *To:* John E Drake <[e-mail]>; Acee Lindem (acee) <
> [e-mail]>; Alexander Vainshtein <[e-mail]>;
> Greg Mirsky <[e-mail]>
> *Cc:* Robert Sparks <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> John -
>
>
>
> *From:* John E Drake [mailto:[e-mail] <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 1:19 PM
> *To:* Les Ginsberg (ginsberg); Acee Lindem (acee); Alexander Vainshtein;
> Greg Mirsky
> *Cc:* Robert Sparks; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; Abhay Roy (akr)
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Les,
>
>
>
> I understand and I have made the same argument in other contexts and with
> similar results (“… and your point is?”).
>
> *[Les:] Nice to know I am not completely alone.:-)*
>
>
>
> *It would be good if the authors/WG at least considered a non-IGP
> approach.*
>
> *However, if the IGP approach is to be taken, the GENINFO definition
> currently in the draft is unacceptable for reasons I have previously given.
> So this should be reworked – probably to use a sub-TLV of TLV 22 et al.*
>
> *The other alternative would be to define a GENINFO application that could
> support advertising many interface attributes – I don’t think anyone wants
> to go in that direction – certainly not me.*
>
>
>
> *   Les*
>
>
>
>
>
> However, as I indicated in my previous email, RTM would be used as part of
> the network infrastructure as a way to provide time synchronization between
> the nodes in the network, so I would consider it similar to the S-BFDs that
> Uma and you were discussing.
>
>
>
> Yours Irrespectively,
>
>
>
> John
>
>
>
> *From:* Les Ginsberg (ginsberg) [mailto:[e-mail]
> <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 4:09 PM
> *To:* John E Drake <[e-mail]>; Acee Lindem (acee) <
> [e-mail]>; Alexander Vainshtein <[e-mail]>;
> Greg Mirsky <[e-mail]>
> *Cc:* Robert Sparks <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> John –
>
>
>
> The text you have excerpted below was trying to say two things:
>
>
>
> 1)If you want to advertise this in the IGPs the OSPF style proposal is
> much better from an implementation standpoint than the IS-IS GENAPP proposal
>
>
>
> 2)There is a larger question as to whether we should be using the IGPs for
> this at all
>
>
>
> Statement #1 should not be interpreted to imply that I am advocating using
> the IGPs. J
>
>
>
> That said, we “ALWAYS” end up choosing using the IGPs to do this sort of
> thing – not because it is the “RIGHT” thing to do architecturally – but
> because it is so convenient.
>
>
>
> I am just asking for folks to pause and think about this a bit more from
> an architectural perspective.
>
>
>
>    Les
>
>
>
>
>
> *From:* John E Drake [mailto:[e-mail] <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 12:20 PM
> *To:* Les Ginsberg (ginsberg); Acee Lindem (acee); Alexander Vainshtein;
> Greg Mirsky
> *Cc:* Robert Sparks; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; Abhay Roy (akr)
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Les,
>
>
>
> Comments inline.
>
>
>
> Yours Irrespectively,
>
>
>
> John
>
>
>
> *From:* Les Ginsberg (ginsberg) [mailto:[e-mail]
> <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 12:25 PM
> *To:* John E Drake <[e-mail]>; Acee Lindem (acee) <
> [e-mail]>; Alexander Vainshtein <[e-mail]>;
> Greg Mirsky <[e-mail]>
> *Cc:* Robert Sparks <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> John –
>
>
>
> For me, this raises the age-old question of when it is/is not appropriate
> to use IGPs for flooding information.
>
>
>
> This is clearly not TE information – you just happen to be using this in
> conjunction with MPLS – but it is a generic capability. I do not see the
> IGPs as the appropriate mechanism to flood generic interface capabilities.
> It also, as Acee has pointed out, results in flooding information to all
> nodes in the domain when only a few care about it.
>
>
>
> *[JD]  RTM support as defined in the draft would be used to provide
> extremely accurate time synchronization in an MPLS network so I would
> suggest that all nodes in such a network would be using it and hence that
> it does belong in the IGP.  As an aside, advertising it in the IGP
> facilitates incremental or partial deployment.  Your yesterday’s email
> supports this:  *
>
>
>
> *“It would seem more appropriate to treat RTM information either as:*
>
>
>
> *   o an extension to link attribute information already advertised by the
> IGPs (as has been suggested for OSPF) - which would suggest in IS-IS a
> sub-TLV of TLV 22(et al)*
>
>
>
> *or*
>
>
>
> ·        *As an interface attribute independent of routing protocols
> which could be retrieved utilizing network management tools”*
>
>
>
>    Les
>
>
>
> *From:* John E Drake [mailto:[e-mail] <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 8:54 AM
> *To:* Acee Lindem (acee); Alexander Vainshtein; Greg Mirsky; Les Ginsberg
> (ginsberg)
> *Cc:* Robert Sparks; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; Abhay Roy (akr)
> *Subject:* RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Acee,
>
>
>
> Relying on an omniscient controller is a non-starter in general and in
> particular because the protocol by which it would learn each node’s RTM
> capabilities and distribute them to the other nodes is undefined.  Further,
> one of the ways by which an omniscient controller learns a node’s
> capabilities is by snooping the link/state database.
>
>
>
> Yours Irrespectively,
>
>
>
> John
>
>
>
> *From:* Acee Lindem (acee) [mailto:[e-mail] <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 11:47 AM
> *To:* John E Drake <[e-mail]>; Alexander Vainshtein <
> [e-mail]>; Greg Mirsky <[e-mail]>;
> Les Ginsberg (ginsberg) <[e-mail]>
> *Cc:* Robert Sparks <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* Re: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Hi John,
>
>
>
> *From: *John E Drake <[e-mail]>
> *Date: *Thursday, January 19, 2017 at 10:43 AM
> *To: *Acee Lindem <[e-mail]>, Alexander Vainshtein <
> [e-mail]>, Greg Mirsky <[e-mail]>,
> "Les Ginsberg (ginsberg)" <[e-mail]>
> *Cc: *Robert Sparks <[e-mail]>, "[e-mail]" <[e-mail]>,
> "[e-mail]" <[e-mail]>, "draft-ietf-mpls-residence-
> [e-mail]" <[e-mail]>, "
> [e-mail]" <[e-mail]>, "[e-mail]" <
> [e-mail]>, "Abhay Roy (akr)" <[e-mail]>
> *Subject: *RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Acee,
>
>
>
> We discussed all of this with you over a year ago and used your guidance
> in adding the indication of RTM capability to OSPF.
>
>
>
> I’m sorry but I focused mainly on the OSPF protocol aspects then and
> didn’t question the use case. This question came up in the IS-IS WG
> discussions.
>
>
>
> Thanks,
>
> Acee
>
>
>
>
>
> Yours Irrespectively,
>
>
>
> John
>
>
>
> *From:* Acee Lindem (acee) [mailto:[e-mail] <[e-mail]>]
> *Sent:* Thursday, January 19, 2017 11:38 AM
> *To:* Alexander Vainshtein <[e-mail]>; Greg
> Mirsky <[e-mail]>; Les Ginsberg (ginsberg) <
> [e-mail]>
> *Cc:* Robert Sparks <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* Re: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> I guess what we were trying to envision the use case and whether it makes
> sense for all the nodes in the IGP routing domain to have this information.
> Would the LSP ingress LSR only need to if the egress LSR supports RTM and
> it is best effort recording for transit LSRs in the path?
>
>
>
> Additionally, if it is needed in the IGPs, should there also be a BGP-LS
> Link Attribute TLV proposed?
>
>
>
> Thanks,
>
> Acee
>
>
>
> *From: *Alexander Vainshtein <[e-mail]>
> *Date: *Thursday, January 19, 2017 at 10:15 AM
> *To: *Greg Mirsky <[e-mail]>, "Les Ginsberg (ginsberg)" <
> [e-mail]>
> *Cc: *Acee Lindem <[e-mail]>, Robert Sparks <[e-mail]>,
> "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>, "
> [e-mail]" <draft-ietf-mpls-residence-
> [e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]"
> <[e-mail]>, "Abhay Roy (akr)" <[e-mail]>
> *Subject: *RE: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Hi all,
>
> I concur with Greg: from my POV an interoperable solution should not
> depend on an omniscient NMS client distributing information about
> capabilities of each node to each other node.
>
>
>
>
>
> Regards,
>
> Sasha
>
>
>
> Office: [phone] <+972%203-926-6302>
>
> Cell:      [phone] <+972%2054-926-6302>
>
> Email:   [e-mail]
>
>
>
> *From:* Greg Mirsky [mailto:[e-mail] <[e-mail]>]
>
> *Sent:* Thursday, January 19, 2017 6:01 PM
> *To:* Les Ginsberg (ginsberg) <[e-mail]>
> *Cc:* Acee Lindem (acee) <[e-mail]>; Robert Sparks <
> [e-mail]>; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; Abhay Roy (akr) <[e-mail]>
> *Subject:* Re: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Hi Les,
>
> I believe that IGP extensions to advertise RTM capability are required.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Thu, Jan 19, 2017 at 7:57 AM, Les Ginsberg (ginsberg) <
> [e-mail]> wrote:
>
> Greg –
>
>
>
> I am having trouble understanding your response.
>
> The question we are raising is whether we should extend the IGPs to
> support advertising RTM capability – an alternative being to retrieve the
> capability via network management.
>
>
>
> Saying that the IGP functionality is optional and/or wouldn’t always be
> advertised doesn’t really answer the question of whether we should or
> should not define the IGP extensions.
>
>
>
> Could you respond more directly to this point?
>
>
>
>    Les
>
>
>
>
>
> *From:* Greg Mirsky [mailto:[e-mail]]
> *Sent:* Thursday, January 19, 2017 7:44 AM
> *To:* Acee Lindem (acee)
> *Cc:* Robert Sparks; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; Les Ginsberg
> (ginsberg); [e-mail]; Abhay Roy (akr)
>
>
> *Subject:* Re: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Hi Acee,
>
> the draft defines optional functionality. If an operator has no use
> neither for PTP's Transparent Clock, nor RTM itself as performance metric,
> then RTM sub-TLV would not be included and thus it would not be flooded. Of
> course, it be right to reflect RTM capability through YANG data model, thus
> allowing SDN scenario you've described.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Wed, Jan 18, 2017 at 2:51 PM, Acee Lindem (acee) <[e-mail]>
> wrote:
>
> Hi Greg,
>
>
>
> Although it is a bit late, we’ve had some discussions amongst the IS-IS
> and OSPF chairs and are wondering whether the interface capability belongs
> in the IGPs. This will be flooded throughout the entire routing domain – is
> it really needed on every node or will it the RTM testing be initiated from
> an omniscient NMS client that would know the capabilities of each node or
> easily query them using YANG?
>
>
>
> Thanks,
>
> Acee
>
>
>
> *From: *mpls <[e-mail]> on behalf of Greg Mirsky <
> [e-mail]>
> *Date: *Wednesday, January 18, 2017 at 1:25 PM
> *To: *Robert Sparks <[e-mail]>
> *Cc: *"[e-mail]" <[e-mail]>, "[e-mail]" <
> [e-mail]>, "[e-mail]" <
> [e-mail]>, "[e-mail]" <
> [e-mail]>
> *Subject: *Re: [mpls] Review of draft-ietf-mpls-residence-time-12
>
>
>
> Hi Robert,
>
> thank you for the most expedient review and comments. I'll make changes in
> Section 2 per your suggestion.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Wed, Jan 18, 2017 at 10:34 AM, Robert Sparks <[e-mail]>
> wrote:
>
> The changes all look good.
>
> I still think you should say something in the document about what "the
> time of packet arrival" and "transmission" means, and call out the point
> you made about being careful to not introduce apparent jitter by not making
> those measurements consistently. (The definitions you point to in your
> earlier mail from G.8013 don't really help - they just say "time of packet
> arrival". Again, the first and last bit are likely to be several
> nanoseconds apart so I think it matters. Perhaps you're saying it doesn't
> matter as long as each node is consistent (there will be error in the
> residence time measurement, but it will be constant at each node, so the
> sum of errors will be constant, and the clocks will be ok?)
>
> Please look at the new first paragraph of section 2 - there's a mix of "as
> case" and "in case" that should be made consistent. I suspect it would be
> easiest to simply say "referred to as using a one-step clock" and "referred
> to as using a two-step clock" or similar.
>
> RjS
>
>
>
> On 1/18/17 12:03 PM, Greg Mirsky wrote:
>
> Hi Robert,
>
> Sasha Vainshtein came with elegant idea to address disconnection between
> discussion of one-step and two-step modes that you've pointed out. We've
> moved Section 7 as sub-section into Section 2 now. Attached are updated
> diff and the proposed new version -13.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Wed, Jan 18, 2017 at 8:13 AM, Greg Mirsky <[e-mail]>
> wrote:
>
> Hi Robert,
>
> once again, thank you for your thorough review and the most detailed
> comments. I've prepared updated version and would greatly appreciate if you
> review the changes and let us know whether your comments been addressed.
> Attached are diff and the new version.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Wed, Jan 11, 2017 at 7:48 AM, Robert Sparks <[e-mail]>
> wrote:
>
> Reviewer: Robert Sparks
> Review result: Ready with Nits
>
> I am the assigned Gen-ART reviewer for this draft. The General Area
> Review Team (Gen-ART) reviews all IETF documents being processed
> by the IESG for the IETF Chair.  Please treat these comments just
> like any other last call comments.
>
> For more information, please see the FAQ at
> <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
>
> Document: draft-ietf-mpls-residence-time-12
> Reviewer: Robert Sparks
> Review Date: 2017-01-10
> IETF LC End Date: 2017-01-17
> IESG Telechat date: 2017-02-02
>
> Summary: Ready (with nits) for publication as a Proposed Standard
>
> I have two primary comments. I expect both are rooted in the authors
> and working group knowing what the document means instead of seeing
> what
> it says or doesn't say:
>
> 1) The document is loose with its use of 'packet', and where TTLs
> appear when
> they are discussed. It might be helpful to rephrase the text that
> speaks
> of RTM packets in terms of RTM messages that are encoded as G-ACh
> messages and
> not refer to packets unless you mean the whole encapsulated packet
> with MPLS
> header, ACH, and G-ACh message.
>
> 2) Since this new mechanic speaks in terms of fractional nanoseconds,
> some
> discussion of what trigger-point you intend people to use for taking
> the
> precise time of a packet's arrival or departure seems warranted. (The
> first and
> last bit of the whole encapsulated packet above are going to appear at
> the
> physical layer many nanoseconds apart at OC192 speeds if I've done the
> math
> right). It may be obvious to the folks discussing this, but it's not
> obvious
> from the document.  If it's _not_ obvious and variation in technique
> is
> expected, then some discussion about issues that might arise from
> different
> implementation choices would be welcome.
>
> The rest of these are editorial nits:
>
> It would help to pull an overview description of the difference
> between
> one-step and two-step much earlier in the document. I suggest in the
> overview
> in section 2. Otherwise, the reader really has to jump forward and
> read section
> 7 before section 3's 5th bullet makes any sense.
>
> In section 3, "IANA will be asked" should be made active. Say "This
> document
> asks IANA to" and point to the IANA consideration section. Apply
> similar
> treatment to the other places where you talk about future IANA
> actions.
>
> There are several places where there are missing words (typically
> articles or
> prepositions). You're less likely to end up with misinterpretations
> during the
> RFC Editor phase if you provide them before the document gets that far
> in the
> process. The spots I found most disruptive were these (this is not
> intended to
> be exhaustive):
>
>   Section 3: "set 1 according" -> "set to 1 according"
>   Section 3: "the Table 19 [IEEE..." -> "Table 19 of [IEEE..."
>   Section 4.2: "Detailed discussion of ... modes in Section 7."
>                         -> "Detailed discussion of ... modes appears
> in Section 7."
>   Section 10: "most of" -> "most of all"
>
> In Setion 3.1 at "identity of the source port", please point into the
> document
> that defines this identity and its representation. I suspect this is a
> pointer
> into a specific section in IEEE.1588.2008].
>
>
>
>
>
>
>
>
>
>
>
>
>
>