Yubao,
Please note that an EVPN PE that s attached to a MH ES, generally speaking, has 
to generate multiple per-ES A-D routes with the ESI of this MH ES in their NLRI.
This happens because:

  *   The set of these routes, in its entirety, must carry the Route Targets of 
all the EVI that are local attached to this MH ES
  *   The number of Route Targets that can be caried in a single BGP Update 
message is limited.

For BGP path selection process not to suppress some of these routes, these 
routes in this set must include different RDs in their NLRI.
Since the set of these routes changes dynamically as new EVIs are attached 
to/detached from the MS EH in question, these RDs have to be auto-generated by 
the PE itself.
This, in its turn requires usage of Type 1 RDs because these can be 
auto-generated by the PEs while remaining globally unique.

The bottom line: Restriction of RDs used in the NLRI of per-ES Ethernet A-D 
routes cannot be relaxed.

Hope this helps.

Regards,
Sasha

From: BESS <[email protected]> On Behalf Of [email protected]
Sent: Monday, May 15, 2023 10:40 AM
To: [email protected]
Cc: [email protected]; [email protected]; 
[email protected]
Subject: [EXTERNAL] Re: [bess] Discussion on rfc7432bis and 
draft-rabadan-bess-evpn-inter-domain-opt-b




Hi Jorge,



I think the description in draft-rabadan-bess-evpn-inter-domain-opt-b is OK. 
But I don't know why the RD of AD per ES route is limited to type 1 RD. That's 
why I talk about this together with rfc7432bis.

If the scenario from draft-rabadan-bess-evpn-inter-domain-opt-b has shown out 
that it will be useful for the RD-type of AD per ES route being consistence 
with MAC-VRF RD, I think maybe it is not necessary for rfc7432bis to keep these 
restraints unchanged. I notice that you are also a co-author of rfc7432bis, how 
do you think from the viewpoint of rfc7432bis?



Thanks,

Yubao




原始邮件
发件人:JorgeRabadan(Nokia)
收件人:王玉保10045807;[email protected];[email protected];
抄送人:[email protected]<mailto:[email protected]>;
日 期 :2023年05月13日 00:23
主 题 :Re: 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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