Actually, draft-ietf-spring-sr-oam-requirement should fade away and not 
progress.

Please see 
https://mailarchive.ietf.org/arch/msg/spring/x8f_1aM4WsPlWzuqsPmL53wF_m4

Martin, can you please update the datatracker state to reflect this, as per 
your email above?

As it relates to this thread:

  *   draft-ietf-spring-sr-oam-requirement contains such a high-level list of 
requirements that is not practically useful.
  *   Those requirements speak to protocol solutions and not to operational 
problems to be solved.
  *   REQ#13 is too generic to be useful. It says *nothing* about transit 
measurements of any kind.
  *   This discussion indicates things other than “ that OAM requirements 
document is useful”.

Thanks,

—
Carlos Pignataro, car...@cisco.com<mailto:car...@cisco.com>


On Nov 16, 2017, at 4:15 AM, Greg Mirsky 
<gregimir...@gmail.com<mailto:gregimir...@gmail.com>> wrote:

Hi Sasha,
many thanks.
I'd point to SR OAM 
Requirements<https://tools.ietf.org/html/draft-ietf-spring-sr-oam-requirement-03>
 (regrettably expired):

   REQ#13:  SR OAM MUST have the ability to measure Packet loss, Packet
            Delay or Delay variation using Active (using synthetic
            probe) and Passive (using data stream) mode.


I think that our discussion indicates that OAM requirements document is useful 
at least for as long as we're developing OAM toolset. And the document will 
benefit from clarification to reflect our discussion that PM may be performed 
both e2e and over SPME.


Regards,

Greg

On Thu, Nov 16, 2017 at 4:11 PM, Alexander Vainshtein 
<alexander.vainsht...@ecitele.com<mailto:alexander.vainsht...@ecitele.com>> 
wrote:
Greg,
I concur with your position: let’s first  of all agree that ability to measure 
traffic carried by an SR-TE LSP in a specific transit node is a require OAM 
function for SR.

I have looked up the SR OAM Use 
Cases<https://datatracker.ietf.org/doc/draft-ietf-spring-oam-usecase/?include_text=1>
 draft, and I did not find any relevant use cases there.
The only time measurements are mentioned is a reference to an expired 
implementation 
report<https://tools.ietf.org/html/draft-leipnitz-spring-pms-implementation-report-00>
 draft discussing delay measurements.  Since delay measurements are in any case 
based on synthetic traffic, and are always end-to-end (one-way or two-way), 
this reference is not relevant, IMHO, for this discussion.

I have added the authors of the SR OAM Use Cases draft to tis thread.

Regards,
Sasha

Office: +972-39266302<tel:+972%203-926-6302>
Cell:      +972-549266302<tel:+972%2054-926-6302>
Email:   
alexander.vainsht...@ecitele.com<mailto:alexander.vainsht...@ecitele.com>

From: mpls [mailto:mpls-boun...@ietf.org<mailto:mpls-boun...@ietf.org>] On 
Behalf Of Greg Mirsky
Sent: Thursday, November 16, 2017 4:28 AM
To: Xuxiaohu <xuxia...@huawei.com<mailto:xuxia...@huawei.com>>
Cc: draft-hegde-spring-traffic-accounting-for-sr-paths 
<draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org<mailto:draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org>>;
 spring <spring@ietf.org<mailto:spring@ietf.org>>; Zafar Ali (zali) 
<z...@cisco.com<mailto:z...@cisco.com>>; mpls 
<m...@ietf.org<mailto:m...@ietf.org>>
Subject: Re: [mpls] [spring] Special purpose labels in 
draft-hegde-spring-traffic-accounting-for-sr-paths

Dear All,
I cannot imagine that operators will agree to deploy network that lacks 
critical OAM tools to monitor performance and troubleshoot the network. True, 
some will brave the challenge and be the early adopters but even they will 
likely request that the OAM toolbox be sufficient to support their operational 
needs. I see that this work clearly describes the problem and why ability to 
quantify the flow behavior at internal nodes is important for efficient network 
operation. First let's discuss whether the case and requirement towards OAM is 
real and valid. Then we can continue to discussion of what measurement method 
to use.

Regards,
Greg

On Thu, Nov 16, 2017 at 10:05 AM, Xuxiaohu 
<xuxia...@huawei.com<mailto:xuxia...@huawei.com>> wrote:
Concur. Although it has some values, it's not cost-efficient from my point of 
view. Network simplicity should be the first priority object. Hence we would 
have to make some compromise.

Best regards,
Xiaohu



________________________________
徐小虎 Xuxiaohu
M:+86-13910161692<tel:+86-13910161692>
E:xuxia...@huawei.com<mailto:xuxia...@huawei.com>
产品与解决方案-网络战略与业务发展部
Products & Solutions-Network Strategy & Business Development Dept
发件人: Zafar Ali (zali)
收件人: Greg 
Mirsky<gregimir...@gmail.com<mailto:gregimir...@gmail.com>>;draft-hegde-spring-traffic-accounting-for-sr-paths<draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org<mailto:draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org>>;mpls<m...@ietf.org<mailto:m...@ietf.org>>;spring<spring@ietf.org<mailto:spring@ietf.org>>
主题: Re: [mpls] [spring] Special purpose labels in 
draft-hegde-spring-traffic-accounting-for-sr-paths
时间: 2017-11-16 02:24:10

Hi,

This draft breaks the SR architecture. I am quoting a snippet from abstract of 
SR Architecture document 
https://tools.ietf.org/html/draft-ietf-spring-segment-routing-13, which states:
“SR allows to enforce a flow through any topological path while maintaining 
per-flow state only at the ingress nodes to the SR domain.”

In addition to creating states at transit and egress nodes, the procedure also 
affects the data plane and makes it unscalable. It also makes controller job 
much harder and error prune. In summary, I find the procedure very complex and 
unscalable.

Thanks

Regards … Zafar


From: spring <spring-boun...@ietf.org<mailto:spring-boun...@ietf.org>> on 
behalf of Greg Mirsky <gregimir...@gmail.com<mailto:gregimir...@gmail.com>>
Date: Wednesday, November 15, 2017 at 11:10 AM
To: 
"draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org<mailto:draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org>"
 
<draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org<mailto:draft-hegde-spring-traffic-accounting-for-sr-pa...@ietf.org>>,
 "m...@ietf.org<mailto:m...@ietf.org>" <m...@ietf.org<mailto:m...@ietf.org>>, 
"spring@ietf.org<mailto:spring@ietf.org>" 
<spring@ietf.org<mailto:spring@ietf.org>>
Subject: [spring] Special purpose labels in 
draft-hegde-spring-traffic-accounting-for-sr-paths

Hi Shraddha,
thank you for very well written and thought through draft. I have these 
questions I'd like to discuss:

  *   Have you thought of using not one special purpose label for both SR Path 
Identifier and SR Path Identifier+Source SID cases but request two special 
purpose labels, one for each case. Then the SR Path Identifier would not have 
to lose the bit for C flag.
  *   And how you envision to collect the counters along the path? Of course, a 
Controller may query LSR for all counters or counters for the particular flow 
(SR Path Identifier+Source SID). But in addition I'd propose to use in-band 
mechanism, perhaps another special purpose label, to trigger the LSR to send 
counters of the same flow with the timestamp out-band to the predefined 
Collector.
  *   And the last, have you considered ability to flush counters per flow. In 
Scalability Considerations you've stated that counters are maintained as long 
as collection of statistics is enabled. If that is on the node scope, you may 
have to turn off/on the collection to flush off some old counters. I think that 
finer granularity, per flow granularity would be useful for operators. Again, 
perhaps the flow itself may be used to signal the end of the measurement and 
trigger release of counters.
Regards,
Greg


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