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

[Ron Bonica <[e-mail]>]

Jeff,

I think that you mean the scope is different..... 

                                     Ron



Juniper Business Use Only

-----Original Message-----
From: Jeff Tantsura <[e-mail]> 
Sent: Saturday, October 10, 2020 3:14 PM
To: Ron Bonica <[e-mail]>
Cc: Dongjie (Jimmy) <[e-mail]>; Peter Psenak <[e-mail]>; Yingzhen Qu <[e-mail]>; Gyan Mishra <[e-mail]>; [e-mail]
Subject: Re: [Lsr] FW: New Version Notification for draft-bonica-lsr-ip-flexalgo-00.txt

[External Email. Be cautious of content]


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]
>>>>>
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