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

[Greg Shepherd <[e-mail]>]

 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
>>
>>
>>
>