> On Nov 3, 2015, at 6:47 PM, Dapeng Liu <[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.
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. I haven’t seen technical merits or strong use cases for the intended method. Lastly, OAM DT team could consider this into the discussion. -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
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