Re: [bess] BDF Election in EVPN VPWS Single-Active Multihoming

Muthu Arul Mozhi Perumal <muthu.arul@gmail.com> Thu, 28 March 2019 11:43 UTC

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From: Muthu Arul Mozhi Perumal <muthu.arul@gmail.com>
Date: Thu, 28 Mar 2019 17:13:30 +0530
Message-ID: <CAKz0y8wQ0izD6UAoVSoNPTQi1eVAUtQfrKD52niw1azXdL9vpA@mail.gmail.com>
To: "Satya Mohanty (satyamoh)" <satyamoh@cisco.com>
Cc: "Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.rabadan@nokia.com>, "bess@ietf.org" <bess@ietf.org>
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Subject: Re: [bess] BDF Election in EVPN VPWS Single-Active Multihoming
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Hi Satya,

Thanks for your response..

I see no harm in stating explicitly how the BDF is to be calculated for the
default DF election algorithm.

I however agree that it can't be generalized for all future DF election
algorithms, so it is better described on a per algorithm basis..

Regards,
Muthu

On Thu, Mar 28, 2019 at 12:17 AM Satya Mohanty (satyamoh) <
satyamoh@cisco.com> wrote:

> Hi Muthu,
>
>
>
> As you mentioned it is straightforward to calculate the BDF in the default
> DF Algorithm by taking the current DF out of reckoning.
>
> It is my personal view that since this is self-evident it need not be
> explicitly stated.
>
> But I will let others decide.
>
>
>
>
>
> Thanks,
>
> --Satya
>
>
>
> *From: *Muthu Arul Mozhi Perumal <muthu.arul@gmail.com>
> *Date: *Monday, March 25, 2019 at 8:22 AM
> *To: *"Satya Mohanty (satyamoh)" <satyamoh@cisco.com>
> *Cc: *"Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.rabadan@nokia.com>,
> "bess@ietf.org" <bess@ietf.org>
> *Subject: *Re: [bess] BDF Election in EVPN VPWS Single-Active Multihoming
>
>
>
> Hi Satya,
>
>
>
> draft-ietf-bess-evpn-df-election-framework also does not describe how the
> BDF is to be calculated for the default DF election algo. Am I missing
> something?
>
>
>
> I think my question still holds:
>
> Though it is straightforward to calculate the BDF by eliminating the DF
> from the candidate list, would an implementation calculating the BDF that
> way for the default DF election algo interoperate without any problem?
>
>
>
> Would it be better to update draft-ietf-bess-evpn-df-election-framework on
> how the BDF is to be calculated in general for any DF election algo
> (including the default DF election algo)?
>
> [Satya] IMHO opinion, much as it appears obvious, we cannot say for
> certain that in every future DF algorithm (that may come into existence),
> the BDF computation will always be as simple as taking the current DF (PE)
> out of reckoning and doing the recomputation.
>
>
>
> Regards,
>
> Muthu
>
>
>
> Best,
>
> --Satya
>
>
>
> On Sat, Mar 23, 2019 at 2:46 AM Satya Mohanty (satyamoh) <
> satyamoh@cisco.com> wrote:
>
> Hi Muthu,
>
>
>
> Yes, the BDF is as per what you have mentioned.
>
> https://tools.ietf.org/html/draft-ietf-bess-evpn-df-election-framework-09
> formally defines it.
>
>
>
> Thanks,
>
> --Satya
>
>
>
> *From: *BESS <bess-bounces@ietf.org> on behalf of Muthu Arul Mozhi
> Perumal <muthu.arul@gmail.com>
> *Date: *Friday, March 22, 2019 at 11:41 AM
> *To: *"Rabadan, Jorge (Nokia - US/Mountain View)" <jorge.rabadan@nokia.com
> >
> *Cc: *"bess@ietf.org" <bess@ietf.org>
> *Subject: *Re: [bess] BDF Election in EVPN VPWS Single-Active Multihoming
>
>
>
> Thanks, Jorge. Need another clarification. RFC 7432 does not describe how
> to calculate the BDF for the default DF algo. Though it is straightforward
> to calculate the BDF by eliminating the DF from the candidate list, would
> an implementation calculating the BDF that way for the default DF algo
> interoperate without any problem?
>
>
>
> Regards,
>
> Muthu
>
>
>
> On Fri, Mar 22, 2019 at 11:45 PM Rabadan, Jorge (Nokia - US/Mountain View)
> <jorge.rabadan@nokia.com> wrote:
>
> Hi,
>
>
>
> Well, everyone has to support the default DF Alg, based on RFC7432. So
> that one for sure. And in addition there are others that have been
> implemented. For instance, Pref DF election has been implemented by
> multiple vendors.
>
> Thanks,
>
> Jorge
>
>
> ------------------------------
>
> *From:* Muthu Arul Mozhi Perumal <muthu.arul@gmail.com>
> *Sent:* Friday, March 22, 2019 10:41
> *To:* Rabadan, Jorge (Nokia - US/Mountain View)
> *Cc:* bess@ietf.org
> *Subject:* Re: [bess] BDF Election in EVPN VPWS Single-Active Multihoming
>
>
>
> Hi Jorge,
>
>
>
> I didn't mean using different algorithms for electing the DF and BFD. I am
> just asking which algorithm is most widely implemented/used for electing
> the DF *and* BDF for EVPN VPWS single-active multihoming.
>
>
>
> Regards,
>
> Muthu
>
>
>
> On Fri, Mar 22, 2019 at 7:47 PM Rabadan, Jorge (Nokia - US/Mountain View) <
> jorge.rabadan@nokia.com> wrote:
>
> The implementations I know use the same DF Alg for DF election _*and*_
> backup DF Election. And I don’t see why you would use something different?
>
> In other words, if you use e.g., Pref based DF Alg, use it for DF and BDF
> elections. Only that the BDF election excludes the DF from the candidate
> list.
>
>
>
> Thx
>
> Jorge
>
>
>
> *From:*BESS <bess-bounces@ietf.org> on behalf of Muthu Arul Mozhi Perumal
> <muthu.arul@gmail.com>
> *Date: *Friday, March 22, 2019 at 4:23 AM
> *To: *"bess@ietf.org" <bess@ietf.org>
> *Subject: *[bess] BDF Election in EVPN VPWS Single-Active Multihoming
>
>
>
> While RFC 8214 doesn't recommend any DF election algorithm capable of
> electing the BDF in EVPN VPWS single-active multihoming for deciding the
> backup PE, any feedback on what is(are) the widely implemented/supported DF
> election  algorithm(s) by vendors?
>
>
>
> Regards,
>
> Muthu
>
>