Re: WGLC BFD Authentication Drafts

Greg Mirsky <> Mon, 02 April 2018 16:34 UTC

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From: Greg Mirsky <>
Date: Mon, 02 Apr 2018 19:34:45 +0300
Message-ID: <>
Subject: Re: WGLC BFD Authentication Drafts
To: Ashesh Mishra <>
Cc: Jeffrey Haas <>, "" <>
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Hi Asheh,
thank you for taking time to review the minutes from BFD WG meeting at
IETF-98. I don't think that we had enough time to discuss in details my

Greg Mirsky: One of the possible modes when the session is up is to use
authentication with periodic timer trigger?

I'd break it into couple more specific questions:

   - can the periodic Optimized Authentication mode be used without
   authorization o state changes;
   - if the answer to the previous question "yes", then when the first
   authorized BFD control packet must be transmitted by the system;
   - does the BFD state machine (section 6.2 RFC 5880) changes resulting
   from introduction of periodic optimized authentication mode;

And additional comments:

   - "For example, the two ends can decide that BFD frames that indicate a
   state change should be authenticated and enable authentication on those
   frames only."

I don't think that nodes "decide" anything but are configured to do

   - "If the two ends have not previously negotiated which frames they will
   transmit or receive with authentication enabled ..."

I couldn't find the negotiation procedure being described in the document.
Is it out-of-band, i.e. by control or management plane, not part of this
BFD enhancement?

   - "The configuration of the periodic authentication interval for BFD CC
   UP frames is an open issue."

I believe that this open issue must be resolved in the definitive manner
before the draft moved to WGLC.


On Sun, Apr 1, 2018 at 6:11 PM, Ashesh Mishra <>

> Hi Greg,
> Your questions in the IETF-98 meeting seemed to stem from the challenges
> of authentication in fast BFD sessions at high scale.
> I'll address the issue in two parts -
> "Is there a need for authenticated BFD sessions?" - I believe we can all
> agree that there is a clear market need for BFD authentication. So we
> should direct the conversation to the way in which we can address this
> requirement.
> "How can authentication work at scale?" - BFD authentication puts
> significant stress on the system and a non-meticulous method alleviates
> this computation pressure. That's the premise of this draft as it presents
> a way to relieve the BFD authentication requirement based on the capability
> of the system to handle the additional stress which maintaining the
> session scale.
> There are some BFD systems in the market, which are not conducive to
> authentication (even the optimized method), where the impediment to
> authentication is due to the implementation details specific to that vendor
> or system.
> I believe all these issues were address during the meeting. Are there any
> specific questions that I missed or any recommendations for the method in
> which the requirements can be addressed?
> Thanks,
> Ashesh
> ------------------------------
> *From:* Rtg-bfd <> on behalf of Greg Mirsky <
> *Sent:* Thursday, March 29, 2018 4:09:32 AM
> *To:* Jeffrey Haas
> *Cc:*
> *Subject:* Re: WGLC BFD Authentication Drafts
> Dear WG Chairs, et. al,
> I cannot support WG LC for draft-ietf-bfd-optimizing-authentication as my
> comments at BFD WG meeting dating back to IETF-98
> <> still
> not have been addressed nor even there was an attempt to address. As I've
> asked to clarify impact of the proposed mechanism, particularly periodic
> authentication, on the BFD State Machine, I'd point that the proposed
> mechanism directly affects BFD security as discussed in RFC 5880 and the
> section Security Considerations in the document, in my view, does not
> adequately reflects that and doesn't explain how the security of the BFD
> session maintained when the periodic authentication is in use.
> Regards,
> Greg
> On Wed, Mar 28, 2018 at 7:38 PM, Jeffrey Haas <> wrote:
> Working Group,
> The authors of the following Working Group drafts have requested
> Working Group Last Call on the following documents:
> Given the overlap of functionality, WGLC will conclude for the bundle
> simultaneously.
> Authors, please positively acknowledge whether or not you know about any
> for your documents.  Progression of the document will not be done without
> that statement.
> Last call will complete on April 20.
> -- Jeff