> On Nov 3, 2015, at 9:10 PM, Dapeng Liu <[email protected]> wrote: > > > > 2015-11-04 11:04 GMT+08:00 Sam Aldrin <[email protected] > <mailto:[email protected]>>: > >> On Nov 3, 2015, at 6:47 PM, Dapeng Liu <[email protected] >> <mailto:[email protected]>> wrote: >> >> >> >> 2015-11-04 10:29 GMT+08:00 Sam Aldrin <[email protected] >> <mailto:[email protected]>>: >> I expressed the same concern at last IETF meeting, as Shahram raised here. >> Haven’t gotten the explanation yet. >> >> If TTL expiry mechanism is used, then the definition of IP TTL will have to >> be redefined in order to make a copy and forward to next hop. >> But if L3 devices have to read into VXLAN header to determine OAM bit is >> set, they need to implement DPI for the same. >> >> As respond to Shahram's question, there are various ways to implement this. >> ACL etc.. > When there is text related to this, we could discuss. Without that, no point > speculating how it could be done. >> >> Secondly, imagine when there exists a loop. In fact, they do exist even in >> controller based networks. >> >> The PD packet has TTL also to avoid this. > Having TTL doesn’t avoid, it may minimize the implosion. >> >> Speaking as an operator, as mentioned yesterday, this will cause packet >> storm and unintended consequences. >> >> We are also operator, we do not see problems here. Maybe we need more >> clarification and offline discussion to make sure our solution be understood >> correctly. > Please talk to your co-authors. I did spend quite a bit of time to explain on > why it doesn’t work. > > > I guess we have answered your question and it indeed works. Disagree. As pointed out, draft text doesn’t provide complete details either.
> > > My take on this is, If you have specific needs and vendors are willing to > make it work for you, please go ahead by all means, and you do not need to > standardize that. > If you really need to standardize it, ensure that it doesn’t break other > networks deployments. And VXLAN or similar protocols within NVo3 or IETF at > large, are meant to be used elsewhere as well, ex: DCI etc. > > This is an informational document. Why can't hardware and software solutions > both coexist. The point is about behavior being changed, not about co-existence. If you are solving the issue, without introducing any changes to VXLAN header and behavior, then informational is the right way to pursue, IMO. > > > I haven’t seen technical merits or strong use cases for the intended method. > > Lastly, OAM DT team could consider this into the discussion. > > There is a need for more efficient tool. There are many ways to achieve that. Just that the proposed method is not the way to achieve that, IMO. -sam > > Dapeng Liu > > -sam > >> >> Thanks for the comments, >> Dapeng Liu >> >> >> Why are we solving the problem when it doesn’t exist? >> >> -sam >> >>> On Nov 3, 2015, at 6:02 PM, Shahram Davari <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> I think your assumption is broken. But you have an alternative method and >>> that is using TTL expiry. >>> >>> Thx >>> SD >>> >>> From: Dacheng Zhang [mailto:[email protected] >>> <mailto:[email protected]>] >>> Sent: Tuesday, November 03, 2015 5:53 PM >>> To: Shahram Davari; [email protected] <mailto:[email protected]> >>> Subject: Re: [nvo3] draft--pang--nvo3--vxlan--path--detection--01 >>> >>> This draft actually proposes a mechanism where the intermediates are >>> required to recognize the vxlan oam packets. If this assumption is broken, >>> the solutions proposed in this draft may not be effective. >>> >>> Cheers >>> >>> Dacheng >>> >>> 发件人: nvo3 <[email protected] <mailto:[email protected]>> on behalf >>> of Shahram Davari <[email protected] <mailto:[email protected]>> >>> 日期: 2015年11月4日 星期三 上午9:33 >>> 至: "[email protected] <mailto:[email protected]>" <[email protected] >>> <mailto:[email protected]>> >>> 主题: [nvo3] draft-‐pang-‐nvo3-‐vxlan-‐path-‐detection-‐01 >>> >>> Hi, >>> >>> This draft needs to address how intermediate L3 routers are going to see >>> these VXLAN OAM packets, since L3 routers just do L3 routing and don’t look >>> at the payload to see it is VXLAN and then see that these are PD OAM >>> packets. The only option I can think of is TTL expiry, otherwise it won’t >>> work, the way it is defined now, >>> >>> Thx >>> Shahram >>> _______________________________________________ nvo3 mailing list >>> [email protected] >>> <mailto:[email protected]>https://www.ietf.org/mailman/listinfo/nvo3 >>> <https://www.ietf.org/mailman/listinfo/nvo3>_______________________________________________ >>> nvo3 mailing list >>> [email protected] <mailto:[email protected]> >>> https://www.ietf.org/mailman/listinfo/nvo3 >>> <https://www.ietf.org/mailman/listinfo/nvo3> >> >> _______________________________________________ >> nvo3 mailing list >> [email protected] <mailto:[email protected]> >> https://www.ietf.org/mailman/listinfo/nvo3 >> <https://www.ietf.org/mailman/listinfo/nvo3> >> >> >> >> >> -- >> >> ------ >> Best Regards, >> Dapeng Liu > > > > > -- > > ------ > Best Regards, > Dapeng Liu
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