Dear Authors of draft-ietf-idr-vpn-prefix-orf,

As a WG member if you still want to proceed with this document I would
recommend to go back and significantly modify proposed encoding.

Such modification should treat all TLVs as equal class citizens including
(if you insist) RD - but making it optional.

Moreover to address typed NLRIs, addition of new TLV carrying the
Route-Type should be added.

With this and other recommended changes the document could go back to WG
review.

Kind regards,
Robert


On Fri, Jan 30, 2026 at 3:45 PM Ketan Talaulikar <[email protected]>
wrote:

> I concur with Robert.
>
> This mechanism introduces a mandatory RD filter. I won't get into the
> debate of the operational value and efficacy of this mechanism - that is
> for operators to report on. I don't see a technical issue with L3VPN.
>
> The same cannot be said about EVPN (and I have not yet considered the
> expanded applicability proposed by the authors to MVPN and VPLS).
>
> Let me elaborate on the issue with using this with EVPN.
> - The goal of this mechanism is to prevent overload of VPN routes from a
> specific PE+VPN-context
> - The primary and mandatory filter is the RD (there are others but they
> supplement RD)
> - Let's say there is an overload of MAC+IP routes and this mechanism kicks
> in. Would that affect the AD per ES route with the same RD? What would be
> its implication?
>
> The question is how this would affect/impact different types of EVPN route
> types given its primary RD filter?
>
> May I request someone from the BESS WG to review this specific aspect
> (broader review is also welcome!) :
> https://www.ietf.org/archive/id/draft-ietf-idr-vpn-prefix-orf-25.html
>
> Thanks,
> Ketan
>
>
> On Fri, Jan 30, 2026 at 7:20 PM Robert Raszuk <[email protected]> wrote:
>
>> Hi Aijun,
>>
>> On Fri, Jan 30, 2026 at 2:37 PM Aijun Wang <[email protected]>
>> wrote:
>>
>>> Hi, Robert:
>>>
>>> The document doesn’t filter the VPN prefixes solely based on RD, it
>>> bases mainly the RT and other additional TLVs.
>>> RD is only one additional parameter that can be used to assist the
>>> filter of the overflow VPN prefixes routes.
>>>
>>
>> The way the draft is written it is actually the other way around. Other
>> optional parameters may augment RD based filtering.
>>
>> See this:
>>
>>       Optional TLVs: Carries potential additional information to provide
>>       extensibility for the VPN Prefix ORF mechanism.  Its format is
>>       shown in Figure 6.
>>
>> Btw there is no "Figure 6" :).
>>
>> And as we all know all other "optional parameters" can also be sent today
>> with other mechanisms for filtering routes.
>>
>> Thx,
>> R.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>>
>>>
>>> Aijun Wang
>>> China Telecom
>>>
>>> On Jan 30, 2026, at 19:36, Robert Raszuk <[email protected]> wrote:
>>>
>>> 
>>> Dear Wei and WG,
>>>
>>> Ad 1 - Nope this does not address my comment as you still can not
>>> distinguish with current encoding of your draft to which NLRI types given
>>> RD applies. So as of today it is not applicable to any AFI/SAFIs with typed
>>> NLRIs (specifically to EVPNs).
>>>
>>> Ad 2 - ok.
>>>
>>> Ad 3 - I have a different opinion.
>>>
>>> But rereading your document there is one more fundamentally incorrect
>>> section:
>>>
>>>
>>>
>>>
>>>
>>> *3.2.  Address Prefix ORF   Using Address Prefix ORF to filter VPN
>>> routes requires a pre-   configuration, but it is impossible to know in
>>> advance which prefix   may exceed the predefined threshold.*
>>>
>>> Please note that RD is part of the prefix. The above comment in section
>>> 3.2 is wrong as it neglects the fact that prefix ORF contains a length
>>> field. So Address Prefix ORF as defined in RFC5292 when used *with the
>>> length of 64* is exactly RD based ORF. In fact it is even more flexible
>>> as subject doc if you use Minlen and Maxlen fields correctly :).
>>>
>>> So using plain vanilla RFC5292 which is already implemented and shipping
>>> completely removes the need to progress the subject document any further. I
>>> don't understand why we are last calling something which has already been
>>> standardized and in general form published as RFC in 2008.
>>>
>>> Kind regards,
>>> Robert
>>>
>>> On Fri, Jan 30, 2026 at 3:54 AM Wei Wang <[email protected]> wrote:
>>>
>>>> Hi Robert,
>>>>
>>>> Thanks for your comments. And please see my in-line replies. If these
>>>> modifications can address your concerns, we will update this draft based on
>>>> them.
>>>>
>>>> Best Regards,
>>>> Wei
>>>>
>>>> Original
>>>> ------------------------------
>>>> From: Robert Raszuk <[email protected]>
>>>> Date: 2026-01-30 02:06
>>>> To: Susan Hares <[email protected]>
>>>> Cc: idr <[email protected]>, Keyur Patel <[email protected]>
>>>> Subject: [Idr] Re: draft-ietf-idr-vpn-prefix-orf-25 - 1 Week WG LC on
>>>> changes (1/29/2026 to 1/5/2026)
>>>>
>>>> Dear WG,
>>>>
>>>> As recommended moving my three comments to this thread:
>>>>
>>>> 1)
>>>>
>>>> > KT> My point was that simply filtering on the RD can accidentally
>>>> affect Route Types 1
>>>> > (as an example) and have severe implications on EVPN services. This
>>>> is not an issue
>>>> > with CP-ORF but specific to this new mechanism. Please consider at
>>>> least warning
>>>> > about this?
>>>>
>>>> IMO warning is not enough.
>>>>
>>>> I would rather either suggest extending the encoding to cover AFI/SAFIs
>>>> with typed NLRIs or make the clear statement that this draft is not
>>>> applicable to AFI/SAFIs with typed NLRIs at all.
>>>> *[WW]: We can add a table about the **AFI and SAFI types applicable to
>>>> this mechanism in Section 4 as follow:*
>>>>
>>>> *+-------+-------------------------------+*
>>>> *|  AFI     |          SAFI                             |*
>>>> *+-------+-------------------------------+*
>>>> *|IPv4/   |MCAST-VPN                          |*
>>>> *|IPv6     |MCAST-VPLS                         |*
>>>> *|            |VPLS                                       |*
>>>> *|            |BGP EVPNs                            |*
>>>> *|            |MPLS-labeled VPN address |*
>>>> *+------+--------------------------------+*
>>>> *|L2VPN |BGP EVPNs                           |*
>>>> *+------+--------------------------------+*
>>>>
>>>> 2)
>>>>
>>>> Also I think there is typo in this sentence:
>>>>
>>>> However, each existing solution has its own limitation as described in
>>>> Section 4.
>>>> it should be
>>>> However, each existing solution has its own limitation as described in
>>>> Section 3.
>>>> *[WW] Thank you! We will modify it in the updated version.*
>>>> 3)
>>>>
>>>> I would also like to see in this specification a clear note or section
>>>> stating that this document violates Proposed Standard RFC4364 as RFC4364
>>>> clearly defines in section 4.1 what RD is all about:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *   An RD is simply a number, and it does not contain any inherent
>>>>  information; it does not identify the origin of the route or the set   of
>>>> VPNs to which the route is to be distributed.  The purpose of the   RD is
>>>> solely to allow one to create distinct routes to a common IPv4   address
>>>> prefix.  Other means are used to determine where to   redistribute the
>>>> route (see Section 4.3).*
>>>>
>>>> RD should never be used for import, export or any sort of filtering and
>>>> it's sole role is to make prefixes unique.
>>>> *[WW]: I think the usage of RD in this document doesn't conflict with
>>>> the description in RFC4364. RD is just a distinguisher carried by VPN
>>>> routers. It is a part of VPN Prefix. We just use this distinguisher to
>>>> filter the VPN routes. It is simliar with that we do the prefixes filter
>>>> via the shorter, common part of the related prefixes.*
>>>>
>>>> Kind regards,
>>>> Robert
>>>>
>>>>
>>>> On Thu, Jan 29, 2026 at 2:41 PM Susan Hares <*[email protected]
>>>> <[email protected]>*> wrote:
>>>>
>>>> Greetings:
>>>>
>>>>
>>>>
>>>> draft-ietf-idr-vpn-prefix-orf-25 has made changes during the AD review.
>>>>
>>>>
>>>>
>>>> This begins a 1-week WG last call on the changes.
>>>>
>>>> If you have concerns regarding the changes, please respond to this
>>>> message.
>>>>
>>>>
>>>>
>>>> If no concerns or objections are raised, this document will enter into
>>>> IETF LC.
>>>>
>>>>
>>>>
>>>> Cheerily, IDR Chairs
>>>>
>>>> [Sue for Keyur Patel (shepherd)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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