Acee,
I misspoke below. The optimization is to include as few
non-RTM capable nodes as possible.
:)
--
Eric
From: mpls [mailto:[email protected]] On Behalf Of Eric Gray
Sent: Tuesday, January 24, 2017 5:36 PM
To: Acee Lindem (acee) <[email protected]>; Stewart Bryant
<[email protected]>; Uma Chunduri <[email protected]>; Les
Ginsberg (ginsberg) <[email protected]>; John E Drake <[email protected]>;
Alexander Vainshtein <[email protected]>; Greg Mirsky
<[email protected]>
Cc: [email protected]; [email protected]; [email protected]; [email protected];
[email protected]; Abhay Roy (akr) <[email protected]>
Subject: Re: [mpls] Review of draft-ietf-mpls-residence-time-12
Acee,
Each included node that does not support RTM introduces a
variable delay component.
This would introduce a potential accuracy impact in conveying
timing information across a network.
While it is not necessary to use a path that is composed
entirely of RTM capable nodes and links, you can minimize this impact by
including as few such nodes as possible. Each such node/link combination that
can be eliminated improves the accuracy, by reducing the variable component.
--
Eric
From: Gen-art [mailto:[email protected]] On Behalf Of Acee Lindem (acee)
Sent: Thursday, January 19, 2017 8:47 PM
To: Stewart Bryant <[email protected]<mailto:[email protected]>>;
Uma Chunduri <[email protected]<mailto:[email protected]>>; Les
Ginsberg (ginsberg) <[email protected]<mailto:[email protected]>>; John E
Drake <[email protected]<mailto:[email protected]>>; Alexander Vainshtein
<[email protected]<mailto:[email protected]>>;
Greg Mirsky <[email protected]<mailto:[email protected]>>
Cc: [email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
Abhay Roy (akr) <[email protected]<mailto:[email protected]>>
Subject: Re: [Gen-art] [mpls] Review of draft-ietf-mpls-residence-time-12
Hi Stewart,
So you are saying in this use case some element would create a path composed
solely of nodes supporting RTM?
Thanks,
Acee
From: Stewart Bryant <[email protected]<mailto:[email protected]>>
Date: Thursday, January 19, 2017 at 5:04 PM
To: Uma Chunduri <[email protected]<mailto:[email protected]>>,
"Les Ginsberg (ginsberg)" <[email protected]<mailto:[email protected]>>, John
E Drake <[email protected]<mailto:[email protected]>>, Acee Lindem
<[email protected]<mailto:[email protected]>>, Alexander Vainshtein
<[email protected]<mailto:[email protected]>>,
Greg Mirsky <[email protected]<mailto:[email protected]>>
Cc: "Abhay Roy (akr)" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
Robert Sparks <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Subject: Re: [mpls] Review of draft-ietf-mpls-residence-time-12
Well one scenario is that you would use SR to create the synchronization path,
in which case you would need it to be in the IGP and flooded.
Stewart
On 19/01/2017 19:40, Uma Chunduri wrote:
I support advertising this in IGP.
>This is clearly not TE information -..
>I do not see the IGPs as the appropriate mechanism to flood generic interface
>capabilities
We have instances where both the above are not met and we flooded information.
https://tools.ietf.org/html/rfc7883 (Les, you co-authored the same!!)
https://tools.ietf.org/html/rfc7880
--
Uma C.
From: mpls [mailto:[email protected]] On Behalf Of Les Ginsberg (ginsberg)
Sent: Thursday, January 19, 2017 9:25 AM
To: John E Drake <[email protected]><mailto:[email protected]>; Acee Lindem
(acee) <[email protected]><mailto:[email protected]>; Alexander Vainshtein
<[email protected]><mailto:[email protected]>;
Greg Mirsky <[email protected]><mailto:[email protected]>
Cc: Abhay Roy (akr) <[email protected]><mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
Robert Sparks <[email protected]><mailto:[email protected]>;
[email protected]<mailto:[email protected]>
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.
Les
From: John E Drake [mailto:[email protected]]
Sent: Thursday, January 19, 2017 8:54 AM
To: Acee Lindem (acee); Alexander Vainshtein; Greg Mirsky; Les Ginsberg
(ginsberg)
Cc: Robert Sparks; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; 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:[email protected]]
Sent: Thursday, January 19, 2017 11:47 AM
To: John E Drake <[email protected]<mailto:[email protected]>>; Alexander
Vainshtein
<[email protected]<mailto:[email protected]>>;
Greg Mirsky <[email protected]<mailto:[email protected]>>; Les Ginsberg
(ginsberg) <[email protected]<mailto:[email protected]>>
Cc: Robert Sparks <[email protected]<mailto:[email protected]>>;
[email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; Abhay Roy (akr)
<[email protected]<mailto:[email protected]>>
Subject: Re: [mpls] Review of draft-ietf-mpls-residence-time-12
Hi John,
From: John E Drake <[email protected]<mailto:[email protected]>>
Date: Thursday, January 19, 2017 at 10:43 AM
To: Acee Lindem <[email protected]<mailto:[email protected]>>, Alexander Vainshtein
<[email protected]<mailto:[email protected]>>,
Greg Mirsky <[email protected]<mailto:[email protected]>>, "Les
Ginsberg (ginsberg)" <[email protected]<mailto:[email protected]>>
Cc: Robert Sparks <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>, "Abhay Roy (akr)"
<[email protected]<mailto:[email protected]>>
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:[email protected]]
Sent: Thursday, January 19, 2017 11:38 AM
To: Alexander Vainshtein
<[email protected]<mailto:[email protected]>>;
Greg Mirsky <[email protected]<mailto:[email protected]>>; Les Ginsberg
(ginsberg) <[email protected]<mailto:[email protected]>>
Cc: Robert Sparks <[email protected]<mailto:[email protected]>>;
[email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; Abhay Roy (akr)
<[email protected]<mailto:[email protected]>>
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
<[email protected]<mailto:[email protected]>>
Date: Thursday, January 19, 2017 at 10:15 AM
To: Greg Mirsky <[email protected]<mailto:[email protected]>>, "Les
Ginsberg (ginsberg)" <[email protected]<mailto:[email protected]>>
Cc: Acee Lindem <[email protected]<mailto:[email protected]>>, Robert Sparks
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>, "Abhay Roy (akr)"
<[email protected]<mailto:[email protected]>>
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: +972-39266302
Cell: +972-549266302
Email:
[email protected]<mailto:[email protected]>
From: Greg Mirsky [mailto:[email protected]]
Sent: Thursday, January 19, 2017 6:01 PM
To: Les Ginsberg (ginsberg) <[email protected]<mailto:[email protected]>>
Cc: Acee Lindem (acee) <[email protected]<mailto:[email protected]>>; Robert Sparks
<[email protected]<mailto:[email protected]>>;
[email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; Abhay Roy (akr)
<[email protected]<mailto:[email protected]>>
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)
<[email protected]<mailto:[email protected]>> 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:[email protected]<mailto:[email protected]>]
Sent: Thursday, January 19, 2017 7:44 AM
To: Acee Lindem (acee)
Cc: Robert Sparks; [email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; Les Ginsberg (ginsberg);
[email protected]<mailto:[email protected]>; 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)
<[email protected]<mailto:[email protected]>> 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 <[email protected]<mailto:[email protected]>> on behalf of
Greg Mirsky <[email protected]<mailto:[email protected]>>
Date: Wednesday, January 18, 2017 at 1:25 PM
To: Robert Sparks <[email protected]<mailto:[email protected]>>
Cc: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
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
<[email protected]<mailto:[email protected]>> 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
<[email protected]<mailto:[email protected]>> 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
<[email protected]<mailto:[email protected]>> 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].
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