Re: PIM BFD RFC

[Greg Mirsky <[e-mail]>]

Hi Gyan,
thank you for bringing draft-ietf-pim-drlb to my attention (I'm
following discussions in PIM WG but was not aware of this use case). Also,
I appreciate you sharing your thoughts on the applicability of RFCs 8562
and 8563 to the GDR use case. With the current scenario, as I
understand it, there could be more than two GDR Candidates on the given LAN
segment. Let us assume that there three such routers. If one is elected as
GDR and another as GBDR, then third is GDROther. If that is the case, then
the mechanism described for DR/BDR/DROther
in draft-ietf-pim-bfd-p2mp-use-case can be used for expedited convergence
of GDR/GDBR/GDROther. Would you agree?

Regards,
Greg

On Tue, Oct 15, 2019 at 9:10 PM Gyan Mishra <[e-mail]> wrote:

>
> Greg
>
> + Mankamana and Benchon
>
> ...from PIM WG & BESS which owns LSM MVPN mLDP / P2MP TE S-PMSI and
> MI-PMSI.
>
> We were discussing PIM BFD use case on this BFD WG thread  and  RFC 8562
> and RFC 8563 covers strictly L3 VPN LSM ( label switched Multicast) LMDT
> (labeled multicast distribution tree) mLDP / P2MP p-tree S-PMSI ( selective
> constrained MDT / Cisco data MDT) MI-PMSI(inclusive MDT for all VRFs) and
> not Ethernet switching LAN based PIM SM BFD.
>
> We have a new draft in the PIM WG PIM DRLB load balancing GDR capability
> and the draft of hashing of ASM PIM RP hash and ASM and SSM S,G hash load
> balancing of traffic across both PIM DR/BDR does significantly help with
> convergence as 50/50 LB split but during failover you still have 50% of the
> traffic that still has to reconverge and SPT tree MRIB/MFIB state has to
> rebuild.
>
>
> https://tools.ietf.org/html/draft-ietf-pim-drlb-11
>
>
> So the BFD PIM Draft would register the PIM protocol and in asynchronous
> mode with echo disabled we can achieve sub millisecond detection time and
> convergence during failover.
>
> So I do think we need a PIM BFD Draft.
>
> Since this falls between multiple WG but since BFD related this would be
> under the BFD WG.
>
> I am part of the BFD WG as well as part of PIM and BESS so I can assist in
> writing the draft if we are all in agreement that this is needed and can
> work with Mankamana and Benchon as well in creating the draft.
>
> Gyan
>
> Sent from my iPhone
>
> On Oct 12, 2019, at 12:07 AM, Greg Mirsky <[e-mail]> wrote:
>
> Hi Gyan,
> thank you for your interest in this draft. We've described how RFC 8562
> BFD for Multipoint Networks <https://datatracker.ietf.org/doc/rfc8562/> can
> be used to shorten convergence in PIM-SM. The similar scenario discussed in
> draft-ietf-bess-mvpn-fast-failover
> <https://datatracker.ietf.org/doc/draft-ietf-bess-mvpn-fast-failover/> where
> p2mp BFD is used by tails to detect the failure of the head/root or the
> multicast tree. If it is required for the head/root to detect a defect of
> the multicast tree toward a tail, we'll turn to RFC 8563 BFD for
> Multipoint  Active Tails <https://datatracker.ietf.org/doc/rfc8563/> as
> in draft-hu-bier-bfd <https://datatracker.ietf.org/doc/draft-hu-bier-bfd/>
> .
> Hope this information would be helpful to you. I always welcome your
> questions.
>
> Regards,
> Greg
>
> On Fri, Oct 11, 2019 at 7:40 PM Gyan Mishra <[e-mail]> wrote:
>
>> Greg
>>
>> I saw your draft on PIM BFD use cases but could not find the RFC on PIM
>> BFD.
>>
>>
>> https://tools.ietf.org/id/draft-mirsky-pim-bfd-p2mp-use-case-02.html
>>
>> Thanks
>>
>> Gyan
>> Verizon Communications
>> Cell-301 502-1347
>>
>>
>> Sent from my iPhone
>>
>> On Oct 11, 2019, at 9:53 PM, Gyan Mishra <[e-mail]> wrote:
>>
>>
>> BFD WG
>>
>> Anyone know what the RFC or draft for PIM BFD support.
>>
>> Thank you
>>
>> Gyan
>> Verizon Communications
>>
>>
>>
>> Sent from my iPhone
>>
>>