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. Secondly, imagine when there exists a loop. In fact, they do exist even in controller based networks. Speaking as an operator, as mentioned yesterday, this will cause packet storm and unintended consequences. Why are we solving the problem when it doesn’t exist? -sam > On Nov 3, 2015, at 6:02 PM, Shahram Davari <[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]] > Sent: Tuesday, November 03, 2015 5:53 PM > To: Shahram Davari; [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] > https://www.ietf.org/mailman/listinfo/nvo3
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