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 _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
