Hi Sasha,

About your suggestion on 7432bis, it’s kind of implicit, but I see no harm in 
adding a sentence.

Thanks.
Jorge

From: Alexander Vainshtein <[email protected]>
Date: Sunday, May 28, 2023 at 1:26 AM
To: Jorge Rabadan (Nokia) <[email protected]>
Cc: [email protected] <[email protected]>, 
[email protected] 
<[email protected]>, [email protected] 
<[email protected]>, [email protected] <[email protected]>
Subject: RE: [EXTERNAL] Re: [bess] Discussion on rfc7432bis and 
draft-rabadan-bess-evpn-inter-domain-opt-b

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Jorge,
Lots of thanks for your response.

Please see inline below.

Regards,
Sasha

From: Jorge Rabadan (Nokia) <[email protected]>
Sent: Tuesday, May 16, 2023 11:42 PM
To: Alexander Vainshtein <[email protected]>; [email protected]
Cc: [email protected]; [email protected]; 
[email protected]
Subject: Re: [EXTERNAL] Re: [bess] Discussion on rfc7432bis and 
draft-rabadan-bess-evpn-inter-domain-opt-b

Hi Sasha,


However,  neither 7432bis nor any other RFC or standard I am aware of says that 
the same IP address PE address of the PE MUST (or, at least, SHOULD) be used as 
the Administrator field of Type 1 RDs in per-ES A-D routes and Type 1 RDs 
assigned to MAC-VRFs.  And this is obviously a precondition for using the 
solution suggested in Section 3.1.2.
[jorge] the example in section 3.1.2 should be enough to clarify that the 
administrator part of the RD is the same. Let us know if that is not the case 
please.
[[Sasha]] This was a comment about 7432bis. IMHO and FWIW it makes sense to 
clarify in this document that the Administrator part of Type 1 RDs used in all 
the EVPN routes advertised by a specific PE SHOULD be the same. What do you 
think?

I also have some doubts regarding solution that is documented in Section 3.1.3 
of the EVPN Inter-Domain Option B draft because:

·         Only implementations that do not use OPTIONAL per EVI EVPN A-D routes 
can benefit from this solution. In all other cases the per EVI Mass Withdrawal 
solution (documented in Section 3.1 of the draft)  would work exactly as well

·         Such implementations could not benefit from aliasing and/or backup 
path EVPN mechanisms (which inherently rely on per EVI EVPN A-D routes) , thus 
severely compromising any benefits of the Mass Withdrawal mechanisms.
[jorge] as discussed earlier, this is documenting viable existing solutions 
with their trade-offs, not mandating any particular one. Both things you point 
out are described in 3.1.3 section. If you don’t think so, please let us know.
[[Sasha]] I have misspoken – my apologies. I should say that I have some doubts 
regarding the practical value of the solution documented in Section 3.1.3 of 
the EVPN Option-B draft. The solution itself is quite clear.

Thanks!
Jorge



From: Alexander Vainshtein 
<[email protected]<mailto:[email protected]>>
Date: Sunday, May 14, 2023 at 10:31 AM
To: Jorge Rabadan (Nokia) 
<[email protected]<mailto:[email protected]>>, 
[email protected]<mailto:[email protected]> 
<[email protected]<mailto:[email protected]>>
Cc: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>>, 
[email protected]<mailto:[email protected]>
 
<[email protected]<mailto:[email protected]>>,
 [email protected]<mailto:[email protected]> 
<[email protected]<mailto:[email protected]>>
Subject: RE: [EXTERNAL] Re: [bess] Discussion on rfc7432bis and 
draft-rabadan-bess-evpn-inter-domain-opt-b

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Jorge, Yubao and all,
A couple of comments.

The current version of 
7432bis<https://clicktime.symantec.com/15t5Zt9SEXGagfrZxwR9z?h=gGcib8S3C26TGyskaohEYo1_njxaFnOgTQKSs6yx1Ww=&u=https://datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-07>
  says that:

·         Per-ES EVPN A-D routes MUST use Type 1 RDs with the Administrator 
field comprising “an IP address of the PE (typically, the loopback address)”

·         Per-EVI EVPN A-D routes and EVPN MAC/IP Advertisement routes 
advertised by an EVPN Instance locally represented by a MAC-VRF use the RD that 
is assigned to this MAC-VRF, and usage of   Type 1 RD with the Administrator 
field comprising “an IP address of the PE (typically, the loopback address)” is 
RECOMMENDED.

RFC 2119 says that “the adjective "RECOMMENDED", mean that there may exist 
valid reasons in particular circumstances to ignore a particular item, but the 
full implications must be understood and carefully weighed before choosing a 
different course”. Therefore, I concur with Jorge that people who decide not to 
assign Type 1 RDs to  MAC-VRFs should bear the consequences in mind, including 
non-applicability of the solution suggested in Section 3.1.2 of the EVPN 
Inter-Domain Option B 
draft<https://clicktime.symantec.com/15t5eiLih8xB6cgVWVpJc?h=op8TeX0Vsru5FkDFaRdxWuqgdODq44ba2I1LrFCkDsg=&u=https://datatracker.ietf.org/doc/html/draft-rabadan-bess-evpn-inter-domain-opt-b%23section-3.1.2>.

However,  neither 7432bis nor any other RFC or standard I am aware of says that 
the same IP address PE address of the PE MUST (or, at least, SHOULD) be used as 
the Administrator field of Type 1 RDs in per-ES A-D routes and Type 1 RDs 
assigned to MAC-VRFs.  And this is obviously a precondition for using the 
solution suggested in Section 3.1.2.

IMHO and FWIW adding a corresponding RECOMMENDATION to the 7432bis draft would 
be very much in place.

I also have some doubts regarding solution that is documented in Section 3.1.3 
of the EVPN Inter-Domain Option B draft because:

·         Only implementations that do not use OPTIONAL per EVI EVPN A-D routes 
can benefit from this solution. In all other cases the per EVI Mass Withdrawal 
solution (documented in Section 3.1 of the draft)  would work exactly as well

·         Such implementations could not benefit from aliasing and/or backup 
path EVPN mechanisms (which inherently rely on per EVI EVPN A-D routes) , thus 
severely compromising any benefits of the Mass Withdrawal mechanisms.

Hopefully these notes will be useful.

Regards,
Sasha




Regards,
Sasha

From: BESS <[email protected]<mailto:[email protected]>> On Behalf Of 
Jorge Rabadan (Nokia)
Sent: Friday, May 12, 2023 7:23 PM
To: [email protected]<mailto:[email protected]>; 
[email protected]<mailto:[email protected]>;
 [email protected]<mailto:[email protected]>
Cc: [email protected]<mailto:[email protected]>
Subject: [EXTERNAL] Re: [bess] Discussion on rfc7432bis and 
draft-rabadan-bess-evpn-inter-domain-opt-b

Hi Yubao,

Thanks for reviewing the document.
I don’t see any conflicting information:


-    On one hand the use of type 1 RD for MAC-VRF is RECOMMENDED in rfc7432bis, 
which means that normally people will have a type 1 RD in MAC-VRFs. If you 
don’t follow that strong recommendation for the MAC-VRF RD, you can’t use the 
documented solutions in 3.1.2 or 3.1.3

-    On the other hand draft-rabadan-bess-evpn-inter-domain-opt-b is 
documenting some existing solutions, but not specifying or imposing any in 
particular..

So I don’t think there is conflicting information. But if you still think we 
should clarify that in draft-rabadan-bess-evpn-inter-domain-opt-b we’ll be 
happy to do it.

Thanks.
Jorge

From: [email protected]<mailto:[email protected]> 
<[email protected]<mailto:[email protected]>>
Date: Friday, May 12, 2023 at 4:54 AM
To: 
[email protected]<mailto:[email protected]>
 
<[email protected]<mailto:[email protected]>>,
 Jorge Rabadan (Nokia) 
<[email protected]<mailto:[email protected]>>, 
[email protected]<mailto:[email protected]> 
<[email protected]<mailto:[email protected]>>
Cc: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>>
Subject: Discussion on rfc7432bis and draft-rabadan-bess-evpn-inter-domain-opt-b

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Hi Authors,



It seems that draft-rabadan-bess-evpn-inter-domain-opt-b has conflicting 
discription with rfc7432 about the RD-type of AD per ES routes:



Section 3.1.3 of draft-rabadan-bess-evpn-inter-domain-opt-b-00:   "If that is 
the case, now the A-D per ES routes can use the route distinguisher assigned to 
the EVPN Instance (or VRF), which is the same one used by the routes type 2 or 
5 for the EVI."

Section 8.2.1 of rfc7432bis: "The Route Distinguisher MUST be a Type 1 RD 
[RFC4364].  The value field comprises an IP address of the PE (typically, the 
loopback address) followed by a number unique to the PE."



The RD of EVI is not always a Type 1 RD but rfc7432 says that the RD of AD per 
ES route MUST be a Type1 RD. If it is not necessary to prevent other RD-types 
from being used in AD per ES routes, is it better for rfc7432bis to change the 
"MUST" to "MAY" ?  I think such change is also compatible.



Thanks,

Yubao

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