Re: [Lsr] FW: New Version Notification for draft-bonica-lsr-ip-flexalgo-00.txt

[Jeff Tantsura <[e-mail]>]

Jie,

The scoop is different, for SR data plane entry uniqueness is in context of SR domain (SID = value + context),
while for IP it is global to the routing domain, FIB entry is a destination, nothing more.

Regards,
Jeff

> On Oct 10, 2020, at 05:47, Ron Bonica <[e-mail]> wrote:
> 
> Hi Jimmie,
> 
> Inline.....
> 
>                    Ron
> 
> 
> Juniper Business Use Only
> 
> -----Original Message-----
> From: Dongjie (Jimmy) <[e-mail]> 
> Sent: Friday, October 9, 2020 11:06 PM
> To: Peter Psenak <[e-mail]>; Ron Bonica <[e-mail]>; Yingzhen Qu <[e-mail]>; Gyan Mishra <[e-mail]>
> Cc: [e-mail]; Jeff Tantsura <[e-mail]>
> Subject: RE: [Lsr] FW: New Version Notification for draft-bonica-lsr-ip-flexalgo-00.txt
> 
> [External Email. Be cautious of content]
> 
> 
> 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?
> 
> [RB] I never thought about this. Is there a use-case? I think that it will work, but I would have to try it before saying for sure.
> 
> 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? 
> 
> [RB] I don't think so. However, you could achieve the same outcome using link colors.
> 
> 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:[e-mail]] On Behalf Of Peter Psenak
>> Sent: Friday, October 9, 2020 11:58 PM
>> To: Dongjie (Jimmy) <[e-mail]>; Ron Bonica 
>> <rbonica=[e-mail]>; Yingzhen Qu 
>> <[e-mail]>; Gyan Mishra <[e-mail]>
>> Cc: [e-mail]; Jeff Tantsura <[e-mail]>
>> 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:[e-mail]] On Behalf Of Ron Bonica
>>>> Sent: Sunday, October 4, 2020 4:34 AM
>>>> To: Yingzhen Qu <[e-mail]>; Peter Psenak 
>>>> <[e-mail]>; Gyan Mishra <[e-mail]>
>>>> Cc: [e-mail]; Jeff Tantsura <[e-mail]>
>>>> 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 <[e-mail]>
>>>> Sent: Saturday, October 3, 2020 2:08 PM
>>>> To: Peter Psenak <[e-mail]>; Gyan Mishra 
>>>> <[e-mail]>; Ron Bonica <[e-mail]>
>>>> Cc: [e-mail]; Jeff Tantsura <[e-mail]>
>>>> 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" <[e-mail]> 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"
>>>> <[e-mail] on behalf of
>>>> ppsenak=[e-mail]>
>>>> 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
>>>>>     [e-mail]
>>>>> 
>>>> https://urldefense.com/v3/__https://nam11.safelinks.protection.outl
>>>> oo
>>>> k.com/
>>>> ?url=https*3A*2F*2Fwww.ietf.org*2Fmailman*2Flistinfo*2Flsr&amp;data
>>>> =
>> 0
>>>> 2
>>>> 
>> *7C01*7Cyingzhen.qu*40futurewei.com*7Cfe03124c6e414e067c2008d86781
>>>> 
>> 6541*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C63737315273986
>>>> 
>> 5126&amp;sdata=WI48cEAan*2FOkDPmVXGurEAjPItNGF9p9PDQIlD1ip0g*3D
>>>> 
>> &amp;reserved=0__;JSUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!X1fRln9MjimeJcR
>>>> EUEIydr-8IIbtNonXMs83eoXvRww6xkaQfVUdNh0kK452GP-G$
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>>> _______________________________________________
>>>> Lsr mailing list
>>>> [e-mail]
>>>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/l
>>>> sr__;!!NEt6yMaO-gk!TeHgIKM4lUZhkYnt_eFt3SshGJtln8PTqhCuZtODomUQWC_H
>>>> z218CE8S8XzlIxAA$
>>> 
>>> 
>> 
>> _______________________________________________
>> Lsr mailing list
>> [e-mail]
>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/lsr_
>> _;!!NEt6yMaO-gk!TeHgIKM4lUZhkYnt_eFt3SshGJtln8PTqhCuZtODomUQWC_Hz218CE
>> 8S8XzlIxAA$