Hi Tianran, thank you for your kind attention to my questions. Please find my notes in-lined below under the GIM>> tag.
Kind regards, Greg On Thu, Apr 2, 2020 at 11:33 PM Tianran Zhou <[email protected]> wrote: > Hi Greg, > > > > Good questions. Please see my reply in line. > > > > Thanks, > > Tianran > > > > *From:* Greg Mirsky [mailto:[email protected]] > *Sent:* Friday, April 3, 2020 6:58 AM > *To:* wangyali <[email protected]> > *Cc:* Acee Lindem (acee) <[email protected]>; Les Ginsberg (ginsberg) < > [email protected]>; Christian Hopps <[email protected]>; [email protected]; > Tianran Zhou <[email protected]> > *Subject:* Re: [Lsr] 答复: A new version of I-D, > draft-liu-lsr-isis-ifit-node-capability-02 > > > > Hi Yali, et al, > > thank you for the interesting discussion. I have several questions about > the purpose of advertising ifit capabilities in IGP (and in general): > > - Do you see a capability to export telemetry information as a > mandatory or optional? > > What’s the context with this question? Frankly, I did not have a deep well > thinking on this question. But in our case, I wish it’s mandatory.. > GIM>> If it is mandatory, then all nodes in a domain support IFIT and, consequently, there's no need to advertise the capability in the homogeneous, IFIT-wise, domain. Would you agree? > > - Do you expect that a segment route to be constructed to prefer > ifit-capable nodes comparing to nodes that are not? > > Yes. This is one use case. As my echo to Robert, we want to achieve the > SLA assurance network. We think the capability for visibility to verify the > SLA compliance, and also the capability to get the accurate measurement for > path computation should be considered. Should be considered from the very > beginning when we compute the path. > GIM>> I understand that IFIT-capability might be used as one of CSPF constraints. But, as I think of it, it can simply be discovered in the course of running on-path telemetry collection. Would you agree? > Thank you for your kind consideration of my questions. > > > > Regards, > > Greg > > > > On Wed, Apr 1, 2020 at 8:13 PM wangyali <[email protected]> wrote: > > Hi Acee, Chris and Les, > > This is Yali. Many thanks for your kind comments and suggestion. > > Besides of signaling MSD by IGP node CAPABILITY TLV, we learned that > there's another RFC7883 that advertising S-BFD discriminators in IS-IS. In > my understand, BFD is a protocol to detect faults in the bidirectional path > between two forwarding engines, including interface, data links, etc. > > Similarly, IFIT provides a complete framework of a family of on-path > telemetry techniques, which are used to monitoring performance metrics of > service flows, e.g. packet loss, delay. So we consider there's a same > methodology with S-BFD that advertising IFIT node capabilities. > > Please let us know your comments and opinion. Thanks. > > Best regards, > Yali > > -----邮件原件----- > 发件人: Acee Lindem (acee) [mailto:[email protected]] > 发送时间: 2020年4月1日 20:29 > 收件人: Tianran Zhou <[email protected]>; Les Ginsberg (ginsberg) < > [email protected]>; Christian Hopps <[email protected]> > 抄送: [email protected]; wangyali <[email protected]> > 主题: Re: [Lsr] A new version of I-D, > draft-liu-lsr-isis-ifit-node-capability-02 > > Speak as WG Member... > > On 4/1/20, 8:08 AM, "Acee Lindem (acee)" <[email protected]> wrote: > > There is also a difference between some of the existing applications > advertised in IGP capabilities. For example, MSD is used with the routing > information to construct SR paths. The information for all these OAM > mechanisms doesn't share this affinity. Also, it seems like a slippery > slope in what is needed for each of the mechanism. > Thanks, > Acee > > On 4/1/20, 4:01 AM, "Lsr on behalf of Tianran Zhou" < > [email protected] on behalf of [email protected]> wrote: > > Hi Les, > > Thanks very much for your suggestion. I have a quick look at > rfc6823. Sounds like a good idea. I will think about it. > > Cheers, > Tianran > > -----Original Message----- > From: Les Ginsberg (ginsberg) [mailto:[email protected]] > Sent: Wednesday, April 1, 2020 1:47 PM > To: Tianran Zhou <[email protected]>; Christian Hopps < > [email protected]> > Cc: wangyali <[email protected]>; [email protected] > Subject: RE: [Lsr] A new version of I-D, > draft-liu-lsr-isis-ifit-node-capability-02 > > Tianran - > > I am very much in agreement with the points Chris has made. > > IGPs do not exist to advertise capabilities/configure applications > - which seems to me to be what you are proposing here. > The fact that you can easily define the encodings does not make it > the right thing to do. > > This issue was discussed at length in the context of > https://tools.ietf.org/html/rfc6823 . If you were proposing to use GENAPP > I would not object - though I do think Chris has correctly pointed out that > NETCONF/YANG is likely a more appropriate solution for your use case. > > Les > > > > -----Original Message----- > > From: Tianran Zhou <[email protected]> > > Sent: Tuesday, March 31, 2020 7:53 PM > > To: Christian Hopps <[email protected]> > > Cc: wangyali <[email protected]>; Les Ginsberg (ginsberg) > > <[email protected]>; [email protected] > > Subject: RE: [Lsr] A new version of I-D, > > draft-liu-lsr-isis-ifit-node-capability-02 > > > > Hi Chris, > > Thanks for your quick reply, and please see inline. > > > > Cheers, > > Tianran > > > > -----Original Message----- > > From: Christian Hopps [mailto:[email protected]] > > Sent: Wednesday, April 1, 2020 10:00 AM > > To: Tianran Zhou <[email protected]> > > Cc: Christian Hopps <[email protected]>; wangyali > > <[email protected]>; Les Ginsberg (ginsberg) < > [email protected]>; > > [email protected] > > Subject: Re: [Lsr] A new version of I-D, > > draft-liu-lsr-isis-ifit-node-capability-02 > > > > > > > > > On Mar 31, 2020, at 9:28 PM, Tianran Zhou < > [email protected]> > > wrote: > > > > > > ZTR> Let's not boil the ocean to compare NETCONF/YANG or > routing > > protocol, which is better. But I did not see the modification to > > routing protocol with some TLVs is a heavy work, or more complex > than > > NETCONF/YANG. I see both are available and useful. > > > > I'm not sure what you mean by boiling the ocean. I'm saying that > YANG > > is built and intended for querying capabilities and configuring > > routers. Why isn't that where you are looking first for > configuring your monitoring application? > > > > ZTR> I know NETCONF can do both query and configuration. And I > know > > resent YANG-Push improvements to reduce the polling. But > routing > > protocol solutions are also widely used for this. There are > already > > many RFCs and implementation practices. We considered both ways, > and > > aimed for different scenarios. > > > > You don't see the major difference between writing a YANG model > vs > > modifying all of the standard IETF routing protocols? > > > > ZTR> I know many differences between NETCONF and routing > protocol. > > There are many details on both interfaces, implementations, > scenarios > > when comparing them. That's what I mean boil the ocean. > > Here I do not know what's the "major difference" you mean? > > > > Thanks, > > Chris. > > _______________________________________________ > Lsr mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/lsr > > > > > _______________________________________________ > Lsr mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/lsr > >
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