Re: [Bier] BIER in IPv6 --- draft-zhang-bier-bierin6-04

[[e-mail]]

Hi Xuesong,






In fact the LL is preferred, because the advantage of BIER forwarding may be lost if IPv6 tunnel is abused.


The wider range address usage is according to section 6.9 in RFC8279.






Thanks,


Sandy









原始邮件



发件人：Gengxuesong(GengXuesong) <[e-mail]>
收件人：Tony Przygienda <[e-mail]>;张征00007940;
抄送人：6MAN <[e-mail]>;BIER WG <[e-mail]>;
日 期 ：2020年03月23日 14:27
主 题 ：RE: BIER in IPv6 --- draft-zhang-bier-bierin6-04






Hi,


 


Thank you for your prompt response, and giving your considerations about these two methods.


I notice that you mentioned:


>>this has a nice side effect of allowing to "jump over non-BIER routers" if addressed to bier prefix


So would this method be the preferred one to cover more scenarios ?


It seems to me that 2 different methods may need more technical considerations for both of them, such as
 , link-local forwarding concerns for option 1 and global-address security concerns for option 2.


 


Best Regards


Xuesong


 


From: Tony Przygienda [mailto:[e-mail]]
Sent: Monday, March 23, 2020 11:21 AM
To: zhang.zheng <[e-mail]>
Cc: Gengxuesong (Geng Xuesong) <[e-mail]>; 6MAN <[e-mail]>; BIER WG <[e-mail]>
Subject: Re: BIER in IPv6 --- draft-zhang-bier-bierin6-04


 


That's a currently ongoing discussions between the auhtors (cc:'ing bier as well)



 



LL has advantages



* the packet cannot "escape" even if it has TTL > 1



* such a scheme can work purely with ND



* it's hard to "send out the wrong interface" albeit v6 allows AFAIR to have same link local on multiple interfaces



 



Originally the draft did not even allow for global addressing (since we want to use v6 as L2-substitute here just like MPLS & non-MPLS encapsulations are used in BIER) but this has a nice side effect of allowing to "jump
 over non-BIER routers" if addressed to bier prefix (which I personally think should be the only allowed global v6 used, otherwise we may end up with BIER frames in funky places and possible "holes" in the replication fabric). Obviously strictly speaking it's
 not necessary since BIER can be carried in plethora of normal unicast tunnels  but bunch of co-auhtors joined and the consensus was to allow it



 



--- tony



 



 




 


On Sun, Mar 22, 2020 at 8:15 PM <[e-mail]> wrote:


Hi Xuesong,

 

Thank you for your question!

The LL address is used by direct connected neighbor.

For the neighbor which is not direct connected, the wider range address should be used.

 

Thanks,

Sandy

 


原始邮件



发件人：Gengxuesong(GengXuesong) <[e-mail]>



收件人：张征00007940;[e-mail] <[e-mail]>;



日 期 ：2020年03月23日 11:03



主 题 ：RE: Re:BIER in IPv6 --- draft-zhang-bier-bierin6-04




Hi Sandy and authors of draft-zhang-bier-bierin6:


 


I have some questions about the section 2 when reading the draft. It is mentioned that:


“If... The destination address in IPv6 header SHOULD be the neighbor's link-local address.


Otherwise... the destination address SHOULD be the BIER prefix of the BFR neighbor.”


Seems like the draft proposes 2 methods of IPv6 header encapsulation.


Could these 2 methods be combined ? If not, what's the use case and design consideration for each method?


 


Best Regards


Xuesong


 


 


 


From:
 ipv6 [mailto:[e-mail]]On Behalf [e-mail]
Sent: Saturday, March 21, 2020 1:43 PM
To: [e-mail]
Subject: Re:BIER in IPv6 --- draft-zhang-bier-bierin6-04


 

Hi,

As co-author of BIERin6 (draft-zhang-bier-bierin6-04), before you read the draft, please let me introduce BIER technology to you at first:

BIER technology, as defined in RFC8279, it's a new multicast technology. The principle is achieving multicast forwarding by hop-by-hop execution.

BIER is a transport protocol, not just a function. As defined in RFC8296, BIER has it's own ethernet encapsulation with ethernet type 0xAB37, and also it can be travelled by MPLS encapsulation.

BIER has it's own OAM function, ECMP function and traceability. etc. through BIER header defined in RFC8296.

 

For travelling through IPv6 only enviroment, we'd like to travel BIER packet by IPv6 encapsulation.

In draft-zhang-bier-bierin6-04, we want to just use a new Next Header type for BIER header carrying.

We want to bring the minimum impact on IPv6 existed execution, and the maximum flexibility for header interoperability.

So if you have any question about draft-zhang-bier-bierin6-04, or about BIER technology itself, please tell me. I'am glad to explain them to you.

 

Thanks,

Sandy

 


原始邮件



发件人：TonyPrzygienda <[e-mail]>



收件人：Michael McBride <[e-mail]>;



抄送人：[e-mail] <[e-mail]>;



日 期 ：2020年03月19日 01:12



主 题 ：Re: BIER in IPv6




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<BIER WG chair hat on>



 


The specific ask here is for the 6man to look over both drafts, i.e.



 


draft-zhang-bier-bierin6



 


and



 


draft-xie-bier-ipv6-encapsulation



 


and verify whether they conform to published IPv6 standards or raise objections/concerns.



 


The requirements document is currently under active work/comments and does not represent any final or wide-consensus state so an opinion on its state is appreciated
 but it should not be used as any final or binding list of requirements as to the targeted solution in BIER WG



 


thanks



 


--- tony




 


On Tue, Mar 17, 2020 at 9:20 PM Michael McBride <[e-mail]> wrote:



Hello,


 


The bier wg could use your ipv6 recommendations. We’ve worked on various solutions to transport a bier header in ipv6. We decided to pause and create a requirements
 document (draft-ietf-bier-ipv6-requirements) to help steer us towards the right solution(s). In that drafts appendix we have a fairly good summary of the various solutions.


 


We’ve started to rally behind two solutions which meet the majority of the requirements: draft-xie-bier-ipv6-encapsulation (bier header in ipv6 EH) and draft-zhang-bier-bierin6
 (bier header as payload using ipv6 NH). The bier chairs today asked to punt the bierv6 topic to 6man for advice before adopting any of these solutions.


 


So here we are seeking your advice. The most simple approach would probably be to give  https://datatracker.ietf.org/doc/draft-ietf-bier-ipv6-requirements/
 a look and scroll down to the appendix to see a summary of the various solutions we’ve been considering.


 


thanks!


mike


 


 


 




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