Hm. That was my impression too, but now looking at the doc again, the phrase "Switch B (OpenFlow <http://groups.geni.net/geni/wiki/OpenFlow>-enabled) will update it's internal OFDP table. Switch B will forward the received OFDP advertisement out all other ports." confused me.
2011/7/14 Murphy McCauley <jam...@nau.edu> > So the normal LLDP multicast address should never be forwarded. No problem > there except that NOX couldn't "see through" intermediate switches there. > > On the other hand, with the OFDP address... OpenFlow switches still won't > forward such messages (NOX looks at them in discovery, but never instructs > the switches to forward them). But non-OF switches will forward them (as > far as I understand it, this is the entire point -- so that NOX can "see > through" such switches). So yes, these messages may be broadcast by non-OF > hardware on the non-OF portion of their network (always stopping when they > hit an OF switch), but it's not actually any worse than any other broadcast > like an ARP. The non-OF portion of the network probably already has to be > capable of dealing with broadcasts (via STP or looplessness or whatever) or > you have big problems anyway. Right? > > -- Murphy > > On Jul 14, 2011, at 1:29 PM, kk yap wrote: > > > Oops.. I read the GENI document again, and Murphy is right in that the > > multicast address is different here. My apologies. > > > > This address will be forwarded by mac bridges though. Won't this be > > risking a broadcast storm? Am I missing something again? > > > > Regards > > KK > > > > > > On 14 July 2011 13:23, kk yap <yap...@stanford.edu> wrote: > >> I believe OFDP uses LLDP as Kyriakos mentioned. So, there is no real > >> difference here. > >> > >> As for the question of discovering a "link" between two OpenFlow > >> switches connected by a non-OpenFlow switch, the link will be > >> discovered if the switch does not process LLDP and thus pass it on. > >> Else, the intermediate switch will consume the LLDP packet. > >> > >> For discovery of only OpenFlow switches, it might be best to use a > >> packet with multicast address (and possibly ethertype) that is > >> different from LLDP (i.e., 802.11ab). The change is not hard but note > >> the consequences. > >> > >> Just my two cents worth. > >> > >> Regards > >> KK > >> > >> 2011/7/14 Murphy McCauley <jam...@nau.edu>: > >>> Right. Someone correct me if I am wrong here, but really the only > >>> difference between OFDP and normal LLDP is that OFDP uses a normal > multicast > >>> address so that it can see connectivity across non-OpenFlow switches. > >>> The purpose being... if you have two OpenFlow switches connected via an > >>> intermediate non-OpenFlow switch, using normal LLDP, you couldn't tell > that > >>> the two OpenFlow switches were connected because the intermediate > switch > >>> would not forward the LLDP packet. "OFDP" style LLDP *does* get > forwarded > >>> by the intermediate, so you *can* tell that the two OpenFlow switches > are > >>> connected. > >>> -- Murphy > >>> On Jul 14, 2011, at 1:45 AM, Kyriakos Zarifis wrote: > >>> > >>> OFDP is a made-up term used to describe how OF uses LLDP packets to > perform > >>> discovery. There is no such thing as an OFDP packet. The packets used > for > >>> discovery are LLDP packets. > >>> On Thu, Jul 14, 2011 at 4:32 AM, wunyuan <wuny...@nchc.narl.org.tw> > wrote: > >>>> > >>>> Hi, > >>>> > >>>> Thanks for your answer. > >>>> > >>>> We observe the information from this URL > >>>> (http://groups.geni.net/geni/wiki/OpenFlowDiscoveryProtocol) > >>>> > >>>> this information is that OFDP advertisements are sent to a "normal" > >>>> multicast MAC (01:23:00:00:00:01), and we find our openflow switch > send the > >>>> lldps to this mac. > >>>> > >>>> We guess the discovery is the OFDP first. > >>>> > >>>> We think our guess may be wrong after we see the discovery.py code. > >>>> > >>>> Therefore, we are not sure that the discovery is the LLDP or the OFDP > now. > >>>> > >>>> Bests, > >>>> > >>>> Wun-Yuan > >>>> > >>>> > >>>> > >>>> 於 2011/7/14 下午 04:03, Kyriakos Zarifis 提到: > >>>> > >>>> Hi, > >>>> I'm not sure if I understand the question, but Discovery uses LLDP > >>>> packets. > >>>> Short description here: > >>>> http://noxrepo.org/noxwiki/index.php/Discovery > >>>> > >>>> On Thu, Jul 14, 2011 at 3:43 AM, wunyuan <wuny...@nchc.narl.org.tw> > wrote: > >>>>> > >>>>> Hi, > >>>>> > >>>>> We have a question about the nox discovery. > >>>>> > >>>>> Our NOX version is NOX 0.9.0(zaku) in our openflow enviroment. > >>>>> > >>>>> We monitor a port of a openflow by wireshark, and we observe that the > >>>>> lldp packets are sent to a multicast MAC (01:23:00:00:00:01). > >>>>> > >>>>> However we see the discovery.py code and find that it isn't like the > >>>>> OFDP. > >>>>> > >>>>> We also monitor the ports of the other OF switch not > directly-connected > >>>>> above openflow switches, but we only see the lldp packets sent by > itself and > >>>>> the lldp packets receviced from neighbor. > >>>>> > >>>>> The discovery seem the LLDP. > >>>>> > >>>>> Which one is the discovery, the LLDP or OFDP? > >>>>> > >>>>> Thanks. > >>>>> > >>>>> Wun-Yuan > >>>>> _______________________________________________ > >>>>> nox-dev mailing list > >>>>> nox-dev@noxrepo.org > >>>>> http://noxrepo.org/mailman/listinfo/nox-dev > >>>> > >>>> > >>> > >>> _______________________________________________ > >>> nox-dev mailing list > >>> nox-dev@noxrepo.org > >>> http://noxrepo.org/mailman/listinfo/nox-dev > >>> > >>> > >>> _______________________________________________ > >>> nox-dev mailing list > >>> nox-dev@noxrepo.org > >>> http://noxrepo.org/mailman/listinfo/nox-dev > >>> > >>> > >> > >
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