Re: [Bier] draft-ietf-bier-ipv6-requirements-09

[Greg Mirsky <[e-mail]>]

Hi Adrian,
you've said:

This deployment case is somewhat niche: multicast is a bit rare, BIER is
not widely deployed for multicast, IPv6 is still (sadly) not ubiquitous,
bridging over IPv6 is a subset of BIER.

I've paused on the second sentence. As I understand it, BIER is designed
specifically for multicast. Perhaps it is not yet as widely deployed
comparing to the overall multicast deployments but I cannot name what else
would benefit from BIER as much as multicast. Is my interpretation close to
the idea of that sentence?

Regards,
Greg

On Mon, Nov 30, 2020 at 3:22 AM Adrian Farrel <[e-mail]> wrote:

> Hey Jeffrey,
>
> It may be because I'm late to the discussion, but when you say...
>
> > With the above, there is simply no need for another solution in my view.
>
> ...this seems to suggest that there is already a solution.
> AFAICS, while you might support only one of the two solutions, there are
> two solutions. Neither has been adopted and neither has been "selected".
>
> You might have better phrased this as "this is simply no need for two
> solutions." It might be true that most people agree with that, but since
> they will only agree if their preferred solution is chosen, it is possibly
> not very helpful.
>
> However, you go on...
>
> > Of course the WG can continue discussing BIERv6 and may determine that
> it is
> > nice to have BIERv6 as well, but we should not bundle them together when
> it
> > comes to adoption.
>
> ...which seems to suggest that you don't think it is harmful to discuss
> two solutions.
> Since the adoption of one on its own is likely to reduce the chances of
> adoption of the other, not bundling the adoptions might be a little
> simplistic. I am not proposing that we poll the adoption of either solution
> first. Nor am I suggesting making it an either/or adoption poll.
>
> So how about this?
>
> - BIER has a history of starting with Experimental work and seeing how it
> develops
> - This deployment case is somewhat niche: multicast is a bit rare, BIER is
> not widely deployed for multicast, IPv6 is still (sadly) not ubiquitous,
> bridging over IPv6 is a subset of BIER.
> - Why not adopt both approaches as Experimental and set some clear terms
> for the experiment?
>
> Cheers,
> Adrian
>
> -----Original Message-----
> From: BIER <[e-mail]> On Behalf Of Jeffrey (Zhaohui) Zhang
> Sent: 28 November 2020 21:54
> To: Michael McBride <[e-mail]>; [e-mail]
> Cc: BIER WG <[e-mail]>; Gyan Mishra <[e-mail]>;
> draft-ietf-bier-ipv6-requirements <
> [e-mail]>; [e-mail] <
> [e-mail]>; Alvaro Retana <[e-mail]>
> Subject: Re: [Bier] draft-ietf-bier-ipv6-requirements-09
>
> To clarify, there is no gap in the BIERin6 solution (besides the new "next
> header" code point). It's just that some text are needed to explain how the
> requirements are met with the BIERin6 solution - whether it is a
> requirement already listed in the current requirements draft, or have been
> brought up in recent mailing list discussions (I know of two in recent
> discussions).
>
> BIERin6 is based on RFC 8296 (plus the new "next header" code point for
> IPv6 encapsulation), and is a generic solution with the following
> properties:
>
> 1. clean layering - BIER over L2/tunnel and it can carry different payload
> types including SRv6
> 2. IPv4/IPv6 independent (of course you need different signaling)
> 3. L2 independent - as long as the L2 header can indicate with a code
> point that a BIER header follows
> 4. tunnel type independent - as long as the tunnel header can indicate
> with a code point that a BIER header follows
> 5. can work one-hop or multi-hop tunnels nicely
> 6. can work with SRv6 based services nicely
>
> With the above, there is simply no need for another solution in my view.
> Of course the WG can continue discussing BIERv6 and may determine that it
> is nice to have BIERv6 as well, but we should not bundle them together when
> it comes to adoption. That's why I suggested in the last BIER session the
> following:
>
> - Adopt BIERin6
> - Discuss BIERv6 further
>
> Jeffrey
>
> -----Original Message-----
> From: Michael McBride <[e-mail]>
> Sent: Saturday, November 28, 2020 2:15 PM
> To: [e-mail]; Jeffrey (Zhaohui) Zhang <[e-mail]>
> Cc: Gyan Mishra <[e-mail]>; Alvaro Retana <
> [e-mail]>; BIER WG <[e-mail]>;
> [e-mail] <[e-mail]>; Tony Przygienda <
> [e-mail]>; draft-ietf-bier-ipv6-requirements <
> [e-mail]>
> Subject: RE: draft-ietf-bier-ipv6-requirements-09
>
> [External Email. Be cautious of content]
>
>
> Hi Greg,
>
> >Thank you Jeffrey and Gyan for sticking with the thread of the
> conversation to advance the discussion. It's clear now that all of the
> requirements >discussed so far can be addressed by the BIERin6 draft if we
> flesh out the discussed gaps.
>
> >I would like to see Jeffrey and Gyan take over as primary authors of
> >BIERin6 to include the gaps discussed here so that it fully encompases
> the requirements so far described, for WG adoption.
>
> I'm sure I'm misinterpreting. What it sounds like you are saying is "I
> want bierin6 to be adopted so let's fix the gaps so we can begin". Since
> both solutions meet the requirements, I'm hoping you meant "Let's fix the
> gaps in bierin6 so we can begin adoption calls for both bierv6 and bierin6".
>
> mike
>
>
> On Mon, Nov 23, 2020 at 4:56 AM Jeffrey (Zhaohui) Zhang <
> [e-mail]>
> wrote:
>
> > Hi Gyan,
> >
> >
> >
> > Great that we reached consensus on BIERin6.
> >
> > Now there are two lingering points alluded to in this thread, but
> > given it’s been such a long and deeply nested tread, I’ll start a new
> > thread about it.
> >
> >
> >
> > Thanks.
> >
> > Jeffrey
> >
> >
> >
> > *From:* Gyan Mishra <[e-mail]>
> > *Sent:* Monday, November 23, 2020 1:32 AM
> > *To:* Jeffrey (Zhaohui) Zhang <[e-mail]>
> > *Cc:* Alvaro Retana <[e-mail]>; BIER WG <[e-mail]>;
> > [e-mail] <[e-mail]>; Tony Przygienda <
> > [e-mail]>; draft-ietf-bier-ipv6-requirements <
> > [e-mail]>; [e-mail]
> > *Subject:* Re: draft-ietf-bier-ipv6-requirements-09
> >
> >
> >
> > *[External Email. Be cautious of content]*
> >
> >
> >
> > Hi Jeffrey
> >
> >
> >
> > That’s the last of my questions related to BIERin6.
> >
> >
> >
> > I thank you for taking the time to go over the BIERin6 draft in detail.
> >
> >
> >
> > We have reached consensus as well as are in sync,  and I now have a
> > better understanding of BIERin6.
> >
> >
> >
> > During the discussions I did mention that maybe in BIERin6 optional
> > IPv6 tunneling should be removed, as it seemed to create some
> > confusion, but now I am clear and as both the L2/tunnel and IPv6
> > L3/tunnel encapsulation single hop or multi hop tunnel both have the
> > clean BIER layering and complement each other I agree they belong
> together in the same draft.
> >
> > Even though L2/tunnel exists today as part of RFC8296 it makes sense
> > to be part of the overall BIERin6 solution.
> >
> >
> >
> > I am clear on the two IANA code points requests required for the
> > optional
> > IPV6 encapsulation option.
> >
> >
> >
> > Over the course of this thread we did touch on some technical reasons
> > why
> > IPV6 encapsulation is necessary which I you mentioned in some of your
> > responses.
> >
> >
> >
> > Overall throughout the discussions I agree that BIERin6 IPV6 tunnel
> > option and BIERv6 are not transitional and are long term solutions and
> > there are reasons why that we can add to the requirements draft as to
> > why IPV6 encapsulation is necessary below:
> >
> >
> >
> > - Operator requirement for IPV6 encapsulated packets  and not L2
> > encapsulation.
> >
> > -FRR
> >
> >
> >
> > I think we are all set to start updating the Requirements draft.
> >
> >
> >
> > In-line Gyan6>
> >
> >
> >
> > Kind Regards
> >
> >
> >
> > Gyan
> >
> >
> >
> > On Sun, Nov 22, 2020 at 10:39 PM Jeffrey (Zhaohui) Zhang <
> > [e-mail]> wrote:
> >
> > Gyan,
> >
> >
> >
> > Please see zzh6> below.
> >
> >
> >
> > *From:* Gyan Mishra <[e-mail]>
> > *Sent:* Sunday, November 22, 2020 9:49 PM
> > *To:* Jeffrey (Zhaohui) Zhang <[e-mail]>
> > *Cc:* Alvaro Retana <[e-mail]>; BIER WG <[e-mail]>;
> > [e-mail] <[e-mail]>; Tony Przygienda <
> > [e-mail]>; draft-ietf-bier-ipv6-requirements <
> > [e-mail]>; [e-mail]
> > *Subject:* Re: draft-ietf-bier-ipv6-requirements-09
> >
> >
> >
> > *[External Email. Be cautious of content]*
> >
> >
> >
> >
> >
> > Hi Jeffrey
> >
> >
> >
> > Agreed we have reached a consensus.
> >
> >
> >
> >
> >
> > Few more questions to iron out understanding.
> >
> >
> >
> > In line gyan4>
> >
> >
> >
> > Zzh6> Apparently there are still disconnects 😊
> >
> >  Gyan> Thank you for all the detailed responses.  We are in sync now!
> >
> > On Sun, Nov 22, 2020 at 8:06 PM Jeffrey (Zhaohui) Zhang <
> > [e-mail]> wrote:
> >
> > Hi Gyan,
> >
> >
> >
> > Yes I believe we’ve reached consensus.
> >
> >
> >
> > Please see zzh5> below about some details.
> >
> >
> >
> > *From:* Gyan Mishra <[e-mail]>
> > *Sent:* Sunday, November 22, 2020 4:19 PM
> > *To:* Jeffrey (Zhaohui) Zhang <[e-mail]>
> > *Cc:* Alvaro Retana <[e-mail]>; BIER WG <[e-mail]>;
> > [e-mail] <[e-mail]>; Tony Przygienda <
> > [e-mail]>; draft-ietf-bier-ipv6-requirements <
> > [e-mail]>; [e-mail]
> > *Subject:* Re: draft-ietf-bier-ipv6-requirements-09
> >
> >
> >
> > *[External Email. Be cautious of content]*
> >
> >
> >
> > Hi Jeffrey
> >
> >
> >
> > This has been a very informative exchange and extremely helpful for
> > all of us to get onto the same page from a basic understanding POV.
> >
> >
> >
> > Much appreciated all your help and feedback helping clarify my confusion.
> >
> >
> >
> > I am answering in-line but now connecting the dots how is in today’s
> > RFC
> > 8296 Non MPLS BIER Ethernet going to transport IPv6?
> >
> >
> >
> > From your answers below it cannot work as we need two IANA code point
> > one for IPv6 next header type and ICMPv6.
> >
> >
> >
> > Zzh5> The existing model/concept works except that we need to two code
> > points if IPv6 tunneling is used for either getting over non-BFRs or
> > for FRR. One may deem non-BFR as a short-term scenario but FRR will be
> > here for the long run.
> >
> >
> >
> >     Gyan4>I am a little confused here with the code points.  For
> > BIERin6 “L2” BIER scenario RFC 8296 Non MPLS BIER Ethernet Ether type
> 0xAB37.
> >
> >
> >
> > Ethernet -0xAB37 l BIER | IPv6 | payload
> >
> >
> >
> > Zzh6> Note that IPv6 header is not needed – it should be Ethernet
> > Zzh6> -0xAB37
> > l BIER | payload. Of course, if SRv6 style VPN must be used, then IPv6
> > header may be inserted between BIER and payload, only for the SRv6
> > style VPN purpose.
> >
> > Gyan> Understood
> >
> > Ethernet -0xAB37 l BIER l ICMPv6 | payload
> >
> >
> >
> > Zzh6> ICMP was mentioned not for encapsulation but for the following:
> >
> >  Gyan6>Understood
> >
> > Zzh6> 2.1.  IPv6 Options Considerations
> >
> >
> >
> >    For directly connected BIER routers, IPv6 Hop-by-Hop or Destination
> >
> >    options are irrelevant and SHOULD NOT be inserted by BFIR on the
> >
> >    BIERin6 packet.  In this case IPv6 header, Next Header field should
> >
> >    be set to TBD.  Any IPv6 packet arriving on BFRs and BFERs, with
> >
> >    multiple extension header where the last extension header has a
> > Next
> >
> >    Header field set to TBD, SHOULD be discard and the node should
> >
> >    transmit an ICMP Parameter Problem message to the source of the
> >
> >    packet (BFIR) with an ICMP code value of TBD10 ('invalid options
> > for
> >
> >    BIERin6').
> >
> >
> >
> > In this particular scenario where adjacent BFRs support Ethernet link
> > layer in an IPV6 environment and  IPv6 or ICMPv6 encapsulation and the
> > need for the next header code point above is the packet format:
> >
> >
> >
> > Excerpt from RFC 8296
> >
> >
> >
> >    Therefore, if a non-MPLS BIER packet is encapsulated in an Ethernet
> >
> >    header, the Ethertype MUST NOT be 0x8847 or 0x8848 [RFC5332
> > <https://urldefense.com/v3/__https://nam11.safelinks.protection.outloo
> > k.com/?url=https*3A*2F*2Furl__;JSUl!!NEt6yMaO-gk!XqcOU1H95lz8ueSP2Cetp
> > u3B5ldFgwQpw2JZW7s_KsspK1DsMPGcaKe-PLU1AClK$
> > defense.com%2Fv3%2F__https%3A%2Ftools.ietf.org%2Fhtml%2Frfc5332__%3B!!
> > NEt6yMaO-gk!TVpj_z-fpnhYihjYO4kRLRrvHGFDKTzS09SdN8jA-VKR14p1w2ObtXPqQ8
> > 4ssHlj%24&amp;data=04%7C01%7Cmichael.mcbride%40futurewei.com%7C97b8a34
> > 14dbe40bd528708d892e35223%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7
> > C637420852351965804%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIj
> > oiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=8EiHsMns5Jut
> > 7s6EmZvJSxvEwUuJKdtE8PbMZyYRBiQ%3D&amp;reserved=0>].  IEEE
> >
> >    has assigned Ethertype 0xAB37 for non-MPLS BIER packets.
> >
> >
> >
> >
> >
> > In the case of BIERin6 optional encapsulation option, in case where
> > operators requires packets forwarded in IPv6 or tunneling over Non BFR
> > packet format below:
> >
> >
> >
> > IPv6 outer header l BIER l Data
> >
> >
> >
> > So here the next header is BIER so corresponding next header code point.
> >
> >
> >
> >
> >
> > So below is for both cases IANA code point allocation for “L2” next
> > header where next header is IPv6 or ICMPV6, and then the optional IPv6
> > encapsulation option where the next header is BIER.
> >
> >
> >
> > Would those be two separate IANA code point requests I what I see from
> > the packet format.
> >
> >
> >
> > IANA L2 scenario:
> >
> > 2 code point requests for L2 for next header IPv6 and ICMP
> >
> >
> >
> > Zzh6> I don’t follow what you’re talking about. If BIER header follows
> > Zzh6> L2
> > header directly, no new code point is needed. It’s just “Ethernet
> > 0xAB37 | BIER | payload”.
> >
> >
> >
> >     Gyan6> Agreed.
> >
> >
> >
> > IANA optional IPv6 scenario:
> >
> > 1 code point request for IPv6 for next header BIER
> >
> >
> >
> > Zzh6> If IPv6 encapsulation is used, either on between directly
> > Zzh6> connected
> > BFRs or indirectly connected BFRs, a new “next header” code point is
> > needed for BIER.
> >
> >  Gyan6>Understood
> >
> >
> > 5
> > <
> https://urldefense.com/v3/__https://nam11.safelinks.protection.outlook.com/?url=https*3A*2F*2Furldefense.com*2Fv3*2F__https*3A*2Ftools.ietf.org*2Fhtml*2Fdraft-zhang-bier-bierin6-07*section-5__*3BIw!!NEt6yMaO-gk!TVpj_z-fpnhYihjYO4kRLRrvHGFDKTzS09SdN8jA-VKR14p1w2ObtXPqQ_dVL5sH*24&amp;data=04*7C01*7Cmichael.mcbride*40futurewei.com*7C97b8a3414dbe40bd528708d892e35223*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637420852351965804*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000&amp;sdata=nEiVnnCjvgjBOe7cymYDxS784YHPeOpsWHsatN25kj0*3D&amp;reserved=0__;JSUlJSUlJSUlKiUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!XqcOU1H95lz8ueSP2Cetpu3B5ldFgwQpw2JZW7s_KsspK1DsMPGcaKe-PHwxls5N$
> >.
> > IANA Considerations
> >
> >
> >
> >
> >
> >    IANA is requested to assign a new "BIER" type for "Next Header" in
> >
> >    the "Assigned Internet Protocol Numbers" registry.
> >
> >
> >
> >    IANA is requested to assign a new "BIERin6" type for "invalid
> >
> >    options" in the "ICMP code value" registry.
> >
> >
> >
> >    IANA is requested to assign a new "BIER IPv6 transportation
> > Sub-sub-
> >
> >    TLV" type in the "OSPFv3 BIER Ethernet Encapsulation sub-TLV"
> >
> >    Registry.
> >
> >
> >
> >    IANA is requested to set up a new "BIER IPv6 transportation
> > Sub-sub-
> >
> >    sub-TLV" type in the "IS-IS BIER Ethernet Encapsulation sub-sub-TLV"
> >
> >    Registry.
> >
> >
> >
> >
> >
> > My point is that the IANA allocation is different as the next header
> > is different for the L2 scenario where next header is IPv6 or ICMPV6,
> > and IPv6 encapsulation scenario where the next header is BIER.
> >
> >
> >
> > Zzh6> If BIER header follows L2 header directly, BIER Ethertype is
> > Zzh6> used
> > (assuming Ethernet is the L2).
> >
> >  Gyan>Understood
> >
> > Based on this point I am making could we just do a RFC8296 bis version
> > and add the IANA code points for IPv6 and ICMPv6.
> >
> >
> >
> > Zzh6> Given the confusion/contention that have happened in the last
> > Zzh6> two
> > years, it is much better to specifically have a spec dedicated to
> > supporting BIER in IPv6.
> >
> >  Gyan6> I think now looking at it holistically speaking I can now see
> > parity between the L2/tunnel and L3/tunnel both also having the clean
> > layering.  So I can see why adding existing L2/tunnel to BIERin6 even
> > though it already exists made sense to bundle into BIERin6 total
> > solution
>
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