Re: [OSPF] OSPF GR and BFD operability

Anil Raj <anilraj85@gmail.com> Wed, 26 August 2015 03:07 UTC

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References: <CAPj3AOpO+o2hBp3J+mPXpwWiho5fMxE97b1SKsHigRfTQSGzjw@mail.gmail.com> <D201F336.2C912%acee@cisco.com> <F3ADE4747C9E124B89F0ED2180CC814F5956187C@xmb-aln-x02.cisco.com> <CAPj3AOok5_dY9mq=95aLji52-MbkwCrCAQisR4T4XipO5JpDfw@mail.gmail.com> <F3ADE4747C9E124B89F0ED2180CC814F595619CA@xmb-aln-x02.cisco.com> <D20212C1.2C975%acee@cisco.com>
Date: Wed, 26 Aug 2015 08:37:55 +0530
Message-ID: <CAPj3AOq+UAJH9muA87SuEbDcGKKA8wFS8KMpu0Xmjfxd2z9MUw@mail.gmail.com>
From: Anil Raj <anilraj85@gmail.com>
To: "Acee Lindem (acee)" <acee@cisco.com>
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Cc: OSPF WG List <ospf@ietf.org>
Subject: Re: [OSPF] OSPF GR and BFD operability
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I got it. Thanks Les for the details and reference.

Regards,
Anil

On Tue, Aug 25, 2015 at 10:11 PM, Acee Lindem (acee) <acee@cisco.com> wrote:

> I agree. Thanks Les for the reference to RFC 5882.
>
> Thanks,
> Acee
>
> From: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
> Date: Tuesday, August 25, 2015 at 12:29 PM
> To: Anil Raj <anilraj85@gmail.com>
> Cc: Acee Lindem <acee@cisco.com>om>, OSPF WG List <ospf@ietf.org>
> Subject: RE: [OSPF] OSPF GR and BFD operability
>
> Anil –
>
>
>
> IF BFD does NOT share fate w the Control plane then what you say is true.
>
>
>
> If BFD shares fate w the control plane then the behavior depends on the
> neighbor knowing that a restart is in progress. If neighbor knows this then
> the BFD down event can be ignored w minimal risk – otherwise you need to
> treat it as a real failure.
>
>
>
>    Les
>
>
>
>
>
> *From:* Anil Raj [mailto:anilraj85@gmail.com <anilraj85@gmail.com>]
> *Sent:* Tuesday, August 25, 2015 8:51 AM
> *To:* Les Ginsberg (ginsberg)
> *Cc:* Acee Lindem (acee); OSPF WG List
> *Subject:* Re: [OSPF] OSPF GR and BFD operability
>
>
>
> Thanks Acess, Les.
>
>
>
> So ideally it is recommended to tear down OSPF adjacency and signal
> topology change, and thus honor BFD notification in this case.
>
>
>
> Regards,
>
> Anil
>
>
>
> On Tue, Aug 25, 2015 at 8:57 PM, Les Ginsberg (ginsberg) <
> ginsberg@cisco.com> wrote:
>
> https://www.rfc-editor.org/rfc/rfc5882.txt Section 4.3
> <https://www.rfc-editor.org/rfc/rfc5882.txt%20Section%204.3> is relevant
> here.
>
>
>
>    Les
>
>
>
>
>
> *From:* OSPF [mailto:ospf-bounces@ietf.org] *On Behalf Of *Acee Lindem
> (acee)
> *Sent:* Tuesday, August 25, 2015 7:54 AM
> *To:* Anil Raj; OSPF WG List
> *Subject:* Re: [OSPF] OSPF GR and BFD operability
>
>
>
> Hi Anil,
>
>
>
> OSPF and OSPFv3 graceful restart pre-dated BFD so this wasn’t explicitly
> covered. However, given that the intension is that the data plane is
> preserved during restart, an implementation could interpret this as a
> topology change and terminate helper mode as documented in section 3.2 of
> RFC 3623.
>
> Hope this helps,
>
> Acee
>
>
>
>
>
>
>
> *From: *OSPF <ospf-bounces@ietf.org> on behalf of Anil Raj <
> anilraj85@gmail.com>
> *Date: *Tuesday, August 25, 2015 at 10:19 AM
> *To: *OSPF WG List <ospf@ietf.org>
> *Subject: *[OSPF] OSPF GR and BFD operability
>
>
>
> Hi,
>
>
>
> I need clarification on the behavior when BFD notifies remote inactivity
> for a OSPF session, when OSPF neighbor is undergoing Graceful restart? OSPF
> router in helper mode will ideally inactivate the restarting neighbor only
> after grace period, and if BFD notifies neighbor down to OSPF, should the
> adjacency be terminated? If not, will it cause a blackhole for the entire
> grace period if the neighbor is actually down?
>
>
>
> Appreciate if you can help here.
>
>
>
> Regards,
>
> Anil
>
>
>
>