Hi Peter, Thanks for your reply. It aligns with my understanding of FAD, which is just a set of constraints for path computation. Thus one Flex-Algo ID could be used with multiple different data planes. Is this understanding correct?
If so, my question is about the scenario below: A group of nodes in a network support FA-128, a sub-group of them bind FA-128 to SR SIDs, another sub-group of them bind FA-128 to IP address. When one node compute an SR path to a destination, can it compute the path to only pass the nodes which bind FA-128 to SR SIDs, and avoid the nodes which bind FA-128 to IP address? If so, how could this node know the binding of FA to different data planes on other nodes? Best regards, Jie > -----Original Message----- > From: Lsr [mailto:lsr-boun...@ietf.org] On Behalf Of Peter Psenak > Sent: Friday, October 9, 2020 11:58 PM > To: Dongjie (Jimmy) <jie.d...@huawei.com>; Ron Bonica > <rbonica=40juniper....@dmarc.ietf.org>; Yingzhen Qu > <yingzhen...@futurewei.com>; Gyan Mishra <hayabusa...@gmail.com> > Cc: lsr@ietf.org; Jeff Tantsura <jefftant.i...@gmail.com> > Subject: Re: [Lsr] FW: New Version Notification for > draft-bonica-lsr-ip-flexalgo-00.txt > > Hi Jimmy, > > > On 09/10/2020 04:59, Dongjie (Jimmy) wrote: > > Hi Ron, > > > > Thanks for explaining the difference between IP Flex-Algo and SR Flex-algo. > > As > you said, the major difference is the data plane. > > > > If my understanding is correct, for one Flex-Algo to be used correctly, the > > set > of nodes need to apply consistent constraints in computation, and bind the FAD > to the same data plane. > > > > Is it possible that different nodes may use the same Flex-Algo with > > different > data plane, e.g. some with SR-MPLS, some with SRv6, and some with pure IP > etc., or each Flex-Algo is always associated with only one data plane? In the > former case, should the flex-algo definition also indicate the data plane(s) > to be > used with the flex-algo? > > let me respond to this query, as this is not specific to Ron's draft. > > FAD is data plane agnostic and is used by all of them. > > thanks, > Peter > > > > > Best regards, > > Jie > > > >> -----Original Message----- > >> From: Lsr [mailto:lsr-boun...@ietf.org] On Behalf Of Ron Bonica > >> Sent: Sunday, October 4, 2020 4:34 AM > >> To: Yingzhen Qu <yingzhen...@futurewei.com>; Peter Psenak > >> <ppse...@cisco.com>; Gyan Mishra <hayabusa...@gmail.com> > >> Cc: lsr@ietf.org; Jeff Tantsura <jefftant.i...@gmail.com> > >> Subject: Re: [Lsr] FW: New Version Notification for > >> draft-bonica-lsr-ip-flexalgo-00.txt > >> > >> Hi Yingzhen, > >> > >> IP Flexible Algorithms are like SR Flexible Algorithms in the following > respects: > >> > >> - Links have IGP metrics, TE metrics, delay metrics and > >> administrative colors > >> - FADs define Flexible Algorithms > >> > >> More specifically, the FAD: > >> > >> - Indicates which metric type the Flexible Algorithm uses > >> - Specifies constraints in terms of link colors that are included or > >> excluded from the Flexible Algorithm. > >> > >> The significant difference between IP Flexible Algorithms and SR > >> Flexible Algorithms is: > >> > >> - SR Flexible Algorithms bind FADs to prefix SIDs or SRv6 locators > >> - IP Flexible Algorithms bind FADs to IPv4 or IPv6 addresses. > >> > >> So, IP Flexible Algorithms can be deployed in any IP network, even in > >> the absence of SR. > >> > >> Ron > >> > >> > >> Juniper Business Use Only > >> > >> -----Original Message----- > >> From: Yingzhen Qu <yingzhen...@futurewei.com> > >> Sent: Saturday, October 3, 2020 2:08 PM > >> To: Peter Psenak <ppse...@cisco.com>; Gyan Mishra > >> <hayabusa...@gmail.com>; Ron Bonica <rbon...@juniper.net> > >> Cc: lsr@ietf.org; Jeff Tantsura <jefftant.i...@gmail.com> > >> Subject: Re: [Lsr] FW: New Version Notification for > >> draft-bonica-lsr-ip-flexalgo-00.txt > >> > >> [External Email. Be cautious of content] > >> > >> > >> Hi Peter, > >> > >> Using flex-algo, a SRv6 locator can be associated with a single algo, > >> which means an IPv6 or IPv4 address can also be associated with a > >> single algo. So my understanding is Ron's proposal is making the > configuration of flex-algo easier? > >> Instead of using the exclude or include list you can configure a > >> loopback address to a flex-algo directly? > >> > >> Thanks, > >> Yingzhen > >> > >> On 10/3/20, 2:47 AM, "Peter Psenak" <ppse...@cisco.com> wrote: > >> > >> Hi Yingzhen, > >> > >> On 02/10/2020 22:15, Yingzhen Qu wrote: > >> > Hi Peter, > >> > > >> > My understanding of flex-algo is that for traffic destined to > >> a prefix on a particular algo, it can only be routed on routers > >> belong to that algo, which also means only routers in that algo > >> calculates how to reach that prefix and install it into the routing > >> table. It seems to me that using flex-algo (section 12 of the > >> draft) it's possible to have a loopback address associated with only > >> one algo, please correct me if I'm missing or misunderstood something. > >> > >> you are right. That is exactly what is being done for flex-algo with > >> SRv6 - locator is associated with a single algo only. The proposal > >> uses > >> the same concept. > >> > >> thanks, > >> Peter > >> > >> > > >> > Thanks, > >> > Yingzhen > >> > > >> > On 10/2/20, 9:43 AM, "Lsr on behalf of Peter Psenak" > >> <lsr-boun...@ietf.org on behalf of > >> ppsenak=40cisco....@dmarc.ietf.org> > >> wrote: > >> > > >> > Gyan, > >> > > >> > On 02/10/2020 18:30, Gyan Mishra wrote: > >> > > All, > >> > > > >> > > With SRv6 and IP based flex algo a generic question as it > applies > >> to > >> > > both. Is it possible to have within a single IGP domain > different > >> sets > >> > > of nodes or segments of the network running different > >> algorithms. > >> > > >> > absolutely. > >> > > >> > > From > >> > > both drafts it sounds like all nodes have to agree on same > >> algorithm > >> > > similar to concept of metric and reference bandwidth all > have to > >> have > >> > > the same style metric and play to the same sheet of music. > >> > > >> > all participating nodes need to agree on the definition of the > >> flex-algo > >> > and advertise the participation. That's it. > >> > > >> > > If there was > >> > > a way to use multiple algorithms simultaneously based on > SFC > >> or services > >> > > and instantiation of specific algorithm based on service to > be > >> > > rendered. Doing so without causing a routing loop or sub > >> optimal > >> > > routing. > >> > > >> > you can certainly use multiple algorithms simultaneously and > use > >> algo > >> > specific paths to forward specific traffic over it. How that is > done > >> > from the forwarding perspective depends in which > forwarding > >> plane you > >> > use. Flex-algo control plane is independent of the forwarding > >> plane. > >> > > >> > > >> > >I thought with flex algo that there exists a feature that on > >> > > each hop there is a way to specify which algo to use hop by > hop > >> similar > >> > > to a hop by hop policy based routing. > >> > > >> > no, there is no hop-by-hop classification, that is problematic > and > >> does > >> > not scale for high speeds. Classification is done at the > ingress only. > >> > > >> > thanks, > >> > Peter > >> > > >> > > > >> > > >> > _______________________________________________ > >> > Lsr mailing list > >> > Lsr@ietf.org > >> > > >> https://urldefense.com/v3/__https://nam11.safelinks.protection.outloo > >> k.com/ > >> ?url=https*3A*2F*2Fwww.ietf.org*2Fmailman*2Flistinfo*2Flsr&data= > 0 > >> 2 > >> > *7C01*7Cyingzhen.qu*40futurewei.com*7Cfe03124c6e414e067c2008d86781 > >> > 6541*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C63737315273986 > >> > 5126&sdata=WI48cEAan*2FOkDPmVXGurEAjPItNGF9p9PDQIlD1ip0g*3D > >> > &reserved=0__;JSUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!X1fRln9MjimeJcR > >> EUEIydr-8IIbtNonXMs83eoXvRww6xkaQfVUdNh0kK452GP-G$ > >> > > >> > > >> > > >> > >> _______________________________________________ > >> 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