Re: [Idr] Notification Subcode Squatting (draft-ietf-idr-bgp-open-policy)

[Jeffrey Haas <[e-mail]>]

Jeffrey,

Could you confirm there are no other unregistered subcodes in use for any of your notifications while you're in there?  :-)

-- Jeff (who audited Juniper's suite a while back but will do so again after the new year)


> On Dec 20, 2021, at 8:20 PM, Jeffrey Chiang (jefchian) <jefchian=[e-mail]> wrote:
> 
> Cisco has implemented https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-multisession-07 many years ago. We are using the subcodes as stated in the draft, but offset by one, because at the time (and now still), subcode 7 was already used. They are
> 8 - Capability Value Mismatch (was called "No Supported AFI/SAFI" in version 00)
> 9 - Grouping Conflict
> 10 - Grouping Required
> We would like to resurrect the draft and progress it to RFC.
> Are there any other implementations?
> 
> Regards,
> Jeffrey
> 
> -----Original Message-----
> From: Idr <[e-mail]> On Behalf Of Susan Hares
> Sent: Sunday, December 19, 2021 7:41 AM
> To: 'Alvaro Retana' <[e-mail]>; [e-mail]
> Cc: [e-mail]; [e-mail]
> Subject: Re: [Idr] Notification Subcode Squatting (draft-ietf-idr-bgp-open-policy)
> 
> Alvaro: 
> 
> Documenting what is out there and pragmatism is the best policy.   
> 
> Q1. Something else 
> 
> If Cisco has been squatting on the subcode 8, cisco experts should let us know: 1) how widely it is deployed, and 2) how difficult to change.    
> If Bird, the same questions apply.  
> 
> Pragmatism 
> 
> Q2. (b) Deprecating the code and (c) working with pragmatism to get actual implementations to registered code. 
> 
> 
> Sue 
> 
> PS - +1 to what Jeff Haas says as well. 
> 
> 
> -----Original Message-----
> From: Idr [mailto:[e-mail]] On Behalf Of Alvaro Retana
> Sent: Wednesday, December 15, 2021 3:53 PM
> To: [e-mail]
> Cc: [e-mail]; [e-mail]; Susan Hares
> Subject: [Idr] Notification Subcode Squatting (draft-ietf-idr-bgp-open-policy)
> 
> Dear idr WG:
> 
> draft-ietf-idr-bgp-open-policy is currently in IETF Last Call.
> 
> This document specifies a new Role Mismatch Notification (code 2, subcode 8).  This value was initially allocated by IANA in 2018 [1].
> 
> Unfortunately, Alexander (cc'd) just pointed out that BIRD uses the same code and subcode combination for a Notification in the case where an AFI/SAFI is not supported. :-(  As far as I can tell, no such Notification is specified anywhere.  However, a quick search points at cisco potentially implementing the same functionality [2] [3] [4] -- some of these reports go as far back as 2010.
> 
> 
> What now?
> 
> Given that there seem to be multiple deployed implementations that use this code/subcode combination, we should avoid using it even if they are squatting on it. :-(  Also, BIRD was one of the two reported implementations for draft-ietf-idr-bgp-open-policy.  So I propose that we request IANA to assign a different value for the new Notification specified in this document.
> 
> Before moving forward, I want to confirm that the WG agrees with the proposal.  Please take a look at the questions below.  I would like to hear from implementers at BIRD and cisco (and any other that I didn't find that might be in the same situation), and from FRR (the second implementation of draft-ietf-idr-bgp-open-policy).
> 
> 
> Q1: Should a new subcode be requested for the Role Mismatch Notification
>    specified in draft-ietf-idr-bgp-open-policy?
> 
> [ ]: Yes.
> [ ]: No, the squatters should update their implementations.
> [ ]: Something else.
> 
> 
> Q2: What should we do with subcode 8?
> 
> [ ]: It should be deprecated (i.e., no one can use it).
> [ ]: Write a specification for an "unsupported AFI/SAFI" Notification.
> [ ]: Something else.
> 
> 
> I will keep this poll open until Jan/5, 2022.
> 
> 
> Thanks!
> 
> Alvaro.
> 
> 
> 
> [1] https://www.iana.org/assignments/bgp-parameters/bgp-parameters.xhtml#bgp-parameters-6
> 
> [2] https://community.cisco.com/t5/routing/bgp-3-notification-erro/td-p/1572684
> 
> [3] https://www.wireshark.org/lists/wireshark-bugs/201607/msg00164.html
> 
> [4] https://bst.cloudapps.cisco.com/bugsearch/bug/CSCsu79206
> 
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