Hi Les, Ok very well.
So till this draft provides a text or reference to some other document how IGPs may use inband telemetry data for real path selection it does not fit to LSR charter. Fair. Hi Chris, I am afraid we are looking at this from completely different perspectives. I consider this data to be a necessity for routing and you simply treat it as some opaque telemetry. If we would think of it in the latter sense sure you would be right. IGP is not a configuration push protocol. Sufficient to observe how BGP became one :) Many thx, R. On Thu, Apr 2, 2020 at 8:46 AM Les Ginsberg (ginsberg) <ginsb...@cisco.com> wrote: > Robert - > > First, +1 to what Chris has said. > > There is nothing in the lfit-capability draft that defines any information > that can be used by IGPs to do what you suggest. > Perhaps it is possible that information gleaned via a telemetry > application could be used by the IGPs to do something like what you suggest > - but this draft is not discussing/defining that. It is simply proposing to > advertise information about the capabilities of the lfit application on a > given node. > > Les > > > -----Original Message----- > > From: Christian Hopps <cho...@chopps.org> > > Sent: Thursday, April 02, 2020 5:13 AM > > To: Robert Raszuk <rob...@raszuk.net> > > Cc: Christian Hopps <cho...@chopps.org>; Les Ginsberg (ginsberg) > > <ginsb...@cisco.com>; wangyali <wangyal...@huawei.com>; Acee Lindem > > (acee) <a...@cisco.com>; lsr@ietf.org; Tianran Zhou > > <zhoutian...@huawei.com> > > Subject: Re: [Lsr] A new version of I-D, > draft-liu-lsr-isis-ifit-node-capability-02 > > > > We have defined a perfectly acceptable and quite powerful way to do query > > and configuration for routers, it's YANG. I'd like to hear why the the > IETF > > standard mechanism for query and configuration can't work for this > > application. > > > > Telemetry is important, I don't think anyone has said or would say that > it isn't, > > but that seems orthogonal to this discussion. > > > > Thanks, > > Chris. > > [as WG member] > > > > > > > On Apr 2, 2020, at 5:17 AM, Robert Raszuk <rob...@raszuk.net> wrote: > > > > > > Hi Les, > > > > > > I would like to respectfully disagree with your assessment. > > > > > > The fact that today's IGP (or for that matter BGP) routing is static > from the > > perspective of not taking into consideration real performance > measurements > > from the data plane to me is a bug not a feature. > > > > > > Building SPT based on static link metrics which in vast majority of > cases > > today are emulated circuits on someone else IP backbone. It was a great > idea > > when you constructed the network with connection oriented paradigm > > (Sonet,SDH, dark fiber, TDM ...) not connection less often best effort > one. > > > > > > So I find this proposal very useful and would vote for adopting it in > LSR WG. > > To me in-situ telemetry is not just some monitoring tool. It is an > extremely > > important element to influence how we compute reachability or at least > how > > we choose active forwarding paths from protocol RIBs to main RIB. > > > > > > If we extended IGPs to carry TE information, if we extended them to > > enable flexible algorithm based path computation I fail to understand why > > would we resist to natively enable all of the above with getting the > inputs > > from real networks to be used as to the parameters to the above mentioned > > tools. > > > > > > Kind regards, > > > R. > > > > > > On Thu, Apr 2, 2020 at 8:32 AM Les Ginsberg (ginsberg) > > <ginsberg=40cisco....@dmarc.ietf.org> wrote: > > > Yali - > > > > > > There is a very significant difference between having IGPs advertise an > > identifier for a service that they use as clients (BFD) and having IGPs > > advertise a set of capabilities/options for a telemetry application > which has > > no direct bearing on the function of the routing protocol. > > > > > > You are not the first to find using IGPs to flood application > information very > > convenient. But this is not the appropriate role for the IGPs and over > the > > years we have consistently resisted attempts to do so. > > > > > > Everything advertised in Router Capabilities today has some close > > relationship with the operation of the protocol. Do some of the existing > > advertisements "bend the rules" a bit more than I would prefer? Yes - but > > there has always been at least a close relationship to routing protocol > > function. > > > Here there is none. > > > > > > If you feel compelled to use IGPs to advertise application > information, you > > have RF6823 available (at least for IS-IS). But it is a "high bar" since > it requires > > you also to use a separate IS-IS instance dedicated to advertising the > > application information (see RFC8202). > > > I think Chris Hopps's suggestion to use Netconf/YANG to > configure/retrieve > > what you need is most likely more attractive - but I will leave that for > you to > > decide. > > > > > > Using IGP Router Capabilities here is wrong in my view. > > > > > > Les > > > > > > > > > > -----Original Message----- > > > > From: wangyali <wangyal...@huawei.com> > > > > Sent: Wednesday, April 01, 2020 8:12 PM > > > > To: Acee Lindem (acee) <a...@cisco.com>; Les Ginsberg (ginsberg) > > > > <ginsb...@cisco.com>; Christian Hopps <cho...@chopps.org> > > > > Cc: lsr@ietf.org; Tianran Zhou <zhoutian...@huawei.com> > > > > Subject: 答复: [Lsr] A new version of I-D, > draft-liu-lsr-isis-ifit-node- > > capability- > > > > 02 > > > > > > > > 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:a...@cisco.com] > > > > 发送时间: 2020年4月1日 20:29 > > > > 收件人: Tianran Zhou <zhoutian...@huawei.com>; Les Ginsberg > > (ginsberg) > > > > <ginsb...@cisco.com>; Christian Hopps <cho...@chopps.org> > > > > 抄送: lsr@ietf.org; wangyali <wangyal...@huawei.com> > > > > 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)" <a...@cisco.com> 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" <lsr- > > boun...@ietf.org > > > > on behalf of zhoutian...@huawei.com> 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:ginsb...@cisco.com] > > > > Sent: Wednesday, April 1, 2020 1:47 PM > > > > To: Tianran Zhou <zhoutian...@huawei.com>; Christian Hopps > > > > <cho...@chopps.org> > > > > Cc: wangyali <wangyal...@huawei.com>; lsr@ietf.org > > > > 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 <zhoutian...@huawei.com> > > > > > Sent: Tuesday, March 31, 2020 7:53 PM > > > > > To: Christian Hopps <cho...@chopps.org> > > > > > Cc: wangyali <wangyal...@huawei.com>; Les Ginsberg > (ginsberg) > > > > > <ginsb...@cisco.com>; lsr@ietf.org > > > > > 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:cho...@chopps.org] > > > > > Sent: Wednesday, April 1, 2020 10:00 AM > > > > > To: Tianran Zhou <zhoutian...@huawei.com> > > > > > Cc: Christian Hopps <cho...@chopps.org>; wangyali > > > > > <wangyal...@huawei.com>; Les Ginsberg (ginsberg) > > > > <ginsb...@cisco.com>; > > > > > lsr@ietf.org > > > > > 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 > > > > <zhoutian...@huawei.com> > > > > > 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 > > > > Lsr@ietf.org > > > > https://www.ietf.org/mailman/listinfo/lsr > > > > > > > > > > > > > > > > > > _______________________________________________ > > > Lsr mailing list > > > Lsr@ietf.org > > > https://www.ietf.org/mailman/listinfo/lsr > >
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