Hi Joel:
For details about the method defined in RFC 6550. It uses the HBH option to
carry the RPLInstaceID. The RPLInstaceID and FlexAlgoID are similar.
Thanks
Zhibo
-----Original Message-----
From: Lsr [mailto:lsr-boun...@ietf.org] On Behalf Of Joel M. Halpern
Sent: Wednesday, September 30, 2020 12:05 PM
Cc: lsr@ietf.org
Subject: Re: [Lsr] New Version Notification for
draft-bonica-lsr-ip-flexalgo-00.txt
I am missing something in this discussion of multiple algorithms.
My understanding of flex-algo whether for MPLS, SRv6, SRH, or IPv6, is that you
need to associated a forwarding label (e.g. MPLS label or IPv6
address) with a specific algorithm so that you can compute the next hope for
the forwarding label using the proper algorithm. Then when a packet arrives,
it is simply forwarded according to the forwarding table (e.g.
FIB, LIB, ..)
If that is so, then I do not understand how a given prefix can be safely
associated with more than one algorithm. I could imagine doing several
calculations according to different algorithms. But how do you decide which
one applies to the packet? As far as I know, flex-algo does not look at the
QoS/CoS/ToS bits.
Yours,
Joel
PS: I will admit that it took until an operator described some "interesting"
constraints before I understood why one would even do this.
On 9/29/2020 11:50 PM, Huzhibo wrote:
> Hi.
>
> Associating multiple algorithms with a given prefix is an interesting topic,
> and I think this can simplify the complexity of FlexAlgo. I wonder if the
> author would consider using cases with multiple algorithms with a given
> prefix.
>
> Thanks
>
> ZHibo
>
> -----Original Message-----
> From: Lsr [mailto:lsr-boun...@ietf.org] On Behalf Of tony...@tony.li
> Sent: Tuesday, September 29, 2020 10:05 PM
> To: Ron Bonica <rbonica=40juniper....@dmarc.ietf.org>
> Cc: lsr@ietf.org
> Subject: Re: [Lsr] New Version Notification for
> draft-bonica-lsr-ip-flexalgo-00.txt
>
>
> Ron,
>
> This is nice. It makes it clear that constraint based path computation need
> not have MPLS overhead for those that don’t want it.
>
> One thing that you don’t talk about is how this gets used, tho that may be
> blindingly obvious: you’ll need all nodes placing their prefixes in the
> RIB/FIB, where it will need to be selected over other path computation for
> the same prefixes. This somewhat precludes the possibility of a given prefix
> being useful in multiple flex-algos.
>
> More text on application would be most welcome, just to ensure that we’re on
> the same page.
>
> Tony
>
>
>> On Sep 29, 2020, at 6:37 AM, Ron Bonica
>> <rbonica=40juniper....@dmarc.ietf.org> wrote:
>>
>>
>> Please review and comment
>>
>> Ron
>>
>>
>>
>> Juniper Business Use Only
>>
>>> -----Original Message-----
>>> From: internet-dra...@ietf.org <internet-dra...@ietf.org>
>>> Sent: Tuesday, September 29, 2020 9:36 AM
>>> To: Parag Kaneriya <pkane...@juniper.net>; Shraddha Hegde
>>> <shrad...@juniper.net>; Ron Bonica <rbon...@juniper.net>; Rajesh M
>>> <mraj...@juniper.net>; William Britto A J <bwill...@juniper.net>
>>> Subject: New Version Notification for
>>> draft-bonica-lsr-ip-flexalgo-00.txt
>>>
>>> [External Email. Be cautious of content]
>>>
>>>
>>> A new version of I-D, draft-bonica-lsr-ip-flexalgo-00.txt
>>> has been successfully submitted by Ron Bonica and posted to the IETF
>>> repository.
>>>
>>> Name: draft-bonica-lsr-ip-flexalgo
>>> Revision: 00
>>> Title: IGP Flexible Algorithms (Flexalgo) In IP Networks
>>> Document date: 2020-09-29
>>> Group: Individual Submission
>>> Pages: 14
>>> URL:
>>> https://urldefense.com/v3/__https://www.ietf.org/id/draft-bonica-
>>> lsr-ip-flexalgo-00.txt__;!!NEt6yMaO-gk!X7PVDP-
>>> FnUA0oCcZMw3Qde6in0C72hu_9hOZ53kPspIarR8fNDyU9Vck80Zbjoij$
>>> Status:
>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-b
>>> o
>>> nica-lsr-
>>> ip-flexalgo/__;!!NEt6yMaO-gk!X7PVDP-
>>> FnUA0oCcZMw3Qde6in0C72hu_9hOZ53kPspIarR8fNDyU9Vck8x7e5ZqI$
>>> Htmlized:
>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/html/dr
>>> a
>>> ft-
>>> bonica-lsr-ip-flexalgo__;!!NEt6yMaO-gk!X7PVDP-
>>> FnUA0oCcZMw3Qde6in0C72hu_9hOZ53kPspIarR8fNDyU9Vck82w_6CyU$
>>> Htmlized:
>>> https://urldefense.com/v3/__https://tools.ietf.org/html/draft-
>>> bonica-lsr-ip-flexalgo-00__;!!NEt6yMaO-gk!X7PVDP-
>>> FnUA0oCcZMw3Qde6in0C72hu_9hOZ53kPspIarR8fNDyU9Vck81_QrJ_p$
>>>
>>>
>>> Abstract:
>>> An IGP Flexible Algorithm computes a constraint-based path and maps
>>> that path to an identifier. As currently defined, Flexalgo can only
>>> map the paths that it computes to Segment Routing (SR) identifiers.
>>> Therefore, Flexalgo cannot be deployed in the absence of SR.
>>>
>>> This document extends Flexalgo, so that it can map the paths that it
>>> computes to IP addresses. This allows Flexalgo to be deployed in any
>>> IP network, even in the absence of SR.
>>>
>>>
>>>
>>>
>>> Please note that it may take a couple of minutes from the time of
>>> submission until the htmlized version and diff are available at
>>> tools.ietf.org.
>>>
>>> The IETF Secretariat
>>>
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