Re: [Bier] MSR6 BOF 1st Issue Category: What is the meaning of “native IPv6"

[Greg Shepherd <[e-mail]>]

Inline:


On Mon, Oct 10, 2022 at 2:06 AM Qiuyuanxiang <[e-mail]> wrote:

> Hi Shep,
>
>
>
> Thanks for providing the information.
>
> From my current understanding of MSR6, I think the difference between MSR6
> and BIERin6 is not only for IPv6 encapsulation, but also for  different
> application scenarios. The use cases discussed in MSR6 BOF and related
> documents  (draft-cheng-msr6-design-consideration &
> draft-liu-msr6-problem-statement), including large-scale network, SD-WAN
> and end-to-end multicast, can be well implemented with MSR6.
>
>
>
> Thanks
>
> Yuanxiang
>

I'll have to disagree with you here. MSR6 is NOT encapsulation; it is
encoding. And we have been asking for unique use cases for quite some time,
but have yet to hear any.

Cheers,
Greg


>
>
> *From:* Greg Shepherd <[e-mail]>
> *Sent:* Friday, September 30, 2022 1:19 AM
> *To:* Greg Mirsky <[e-mail]>
> *Cc:* Yisong Liu <[e-mail]>; [e-mail];
> [e-mail]; [e-mail]; BIER WG <[e-mail]>
> *Subject:* Re: MSR6 BOF 1st Issue Category: What is the meaning of
> “native IPv6"
>
>
>
> This conjecture that BIER is an "MPLS solution" continues to arise despite
> the publication of RFC8296 and the IEEE ethertype assignment of 0xAB37 for
> non-MPLS BIER packets. And the adopted draft BIERin6, which Greg mentions
> below, follows the architecture as defined in RFC8296 for IPv6
> encapsulation.
>
>
>
> - Shep
>
>
>
> On Wed, Sep 28, 2022 at 3:16 PM Greg Mirsky <[e-mail]> wrote:
>
> Hi Yisong,
>
> thank you for sharing your perspective on multicast technology for IPv6
> networks. My understanding of your comparison of BIER with MSR6-TE is that
> you consider BIER only as applicable in MPLS networks despite BIER WG
> adopting BIERin6
> <https://datatracker.ietf.org/doc/draft-ietf-bier-bierin6/> that
> "describes how the existing BIER encapsulation specified in RFC8296 works
> in a non-MPLS IPv6 network". Hence my question: What, in your opinion, is a
> limitation of the BIERin6 solution that requires the introduction of yet
> another IPv6 Extension Header, thus adding to the complexity of multicast
> in the IPv6 network?
>
>
>
> Regards,
>
> Greg
>
>
>
> On Wed, Sep 28, 2022 at 1:05 AM Yisong Liu <[e-mail]>
> wrote:
>
> Hi Joel,
>
>
>
> Thanks for your response!
>
> To your further question: “*Your descriptions here do not explain why
> using a new routing header is better than using BIER, or any of the other
> approaches that are being proposed for enhancing multicast handling.  It
> still requires that the replication devices be enhanced with new forwarding
> plane capabilities*.” Here is some response:
>
> MSR6 is a stateless multicast based on IPv6 data plane by using explicit
> encoding the destination nodes and optionally the intermediate nodes along
> the path to these destination nodes in the IPv6 extension header(s). MSR6
> is designed for SP or network domain which uses IPv6 rather than MPLS or
> other data plane.
>
> Besides the MSR6-TE case, here are the core benefits comparing to the BIER
> work.:
>
> 1．  Allocation and management of IPv6 addresses.
>
> 2．  Simplify the Service identifier by using IPv6 address without further
> requiring VXLAN/GENEVE
>
> 3．  Securing the Service Provider network based on the IPv6 address
> management mentioned above.
>
> 4．  Reusing IPv6 extension header and the corresponding function, e.g.,
> ESP;
>
> All these benefits coming from building on IPv6 data plane, and re-using
> the architecture of SRv6. And the benefits have already been discussed and
> agreed (in some degree especially with the SP who are willing to deploy
> IPv6) in SRv6 .
>
>
>
> Best Regards
>
> Yisong Liu
>
>
>
> *发件人:* Yisong Liu <[e-mail]>
> *发送时间:* 2022年9月21日 15:49
> *收件人:* '[e-mail]' <[e-mail]>
> *抄送:* '[e-mail]' <[e-mail]>; '[e-mail]' <
> [e-mail]>; '[e-mail]' <[e-mail]>; '
> [e-mail]' <[e-mail]>
> *主题:* MSR6 BOF 1st Issue Category: What is the meaning of “native IPv6"
>
>
>
> Hi all
>
>
>
> Here are the responses for the 1st Issue Category: What is the meaning of
> “native IPv6”?, including issue 1-3.
>
>
>
> What do you mean by native IPv6?
> <https://github.com/MSR6-community/MSR6-Issue-List/issues/1> #1
>
> *[Response] *We use native IPv6 to describe IPv6 packet running on some
> media (or data-link layer). E.g., RFC2529 mentions “native IPv6 over most
> media / ATM” and “IPv6 over IPv4 tunnels” , the latter is treated as
> opposite concept of “native IPv6”.It is also mentioned in the discussion:
> “if you are using new forwarding information, this is not native. Putting
> multicast forwarding information in an IPv6 EH is not native”. IPv6 EH
> brings extra forwarding behavior, and it is explained in the next response.
>
>
>
> What is alternative to native IPv6? IPv6 includes IPv6 EH and SRv6?
> <https://github.com/MSR6-community/MSR6-Issue-List/issues/2> #2
>
> *[Response] *As in the answer to issue #1, the alternative to native IPv6
> is IPv6 over some kind of tunnel. E.g, IPv6 over IPv4 tunnel, or IPv6 over
> MPLS tunnel. In our understanding, IPv6 header and IPv6 header with EH, as
> SRv6, both belong to “native IPv6”, as long as it is not running over
> some tunnel. E.g., RFC8200 says, “The changes from IPv4 to IPv6 fall
> primarily into the following categories ... Improved Support for Extensions
> and Options.”
>
>
>
> Don’t like hearing this is called “native IPv6”. Because this also
> involves a different encapsulation and is not existing IPv6 encapsulation
> and parse process
> <https://github.com/MSR6-community/MSR6-Issue-List/issues/3> #3
>
> *[Response] *Yes, MSR6 also involves encapsulating an original multicast
> packet into an IPv6 header with an extension header. As the response in the
> previous 2 questions, we think it is in the scope of “native IPv6”, over
> no tunnel .If people still have any concern of using “native IPv6”, maybe
> we could consider to modify the term to for example “ solution based on
> IPv6 data plane” ?
>
>
>
> If you have further comments, please let us know.
>
>
>
>
>
> Best Regards
>
> Yisong Liu
>
>
>
>
> -------------------------------------------------------------------------------------------------------------------------------------
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