Thanks for the ideas Russell - this is definitely fun - I will try that when I am back from a sub-trip (trip in a trip) on 2nd January.
On Fri, Dec 27, 2019, 01:13 Russell Senior <[email protected]> wrote: > For reference, this is what the full-blown output of "swconfig dev switch0 > show" from the MT7621 looks like: > > http://sprunge.us/YPQwYE > > On Thu, Dec 26, 2019 at 4:07 PM Russell Senior <[email protected]> > wrote: > > > > > > > On Thu, Dec 26, 2019 at 3:54 PM Russell Senior < > [email protected]> > > wrote: > > > >> Ooh, try this: shell in and run: swconfig dev switch0 show | grep port > >> > >> Connect your loop and run it again. > >> > >> Then, seeing which port link state changed, you'll know what switch > ports > >> are LAN1 and LAN2. Piping to less instead of grep should give you a > bunch > >> of port stats. > >> > > > > It might not give as verbose of port stats as I suggested. The swconfig > > output for my "Atheros AR8316 rev. 1 switch" isn't nearly as verbose as > the > > one in my mediatek MT7621-based router. But I don't have yours, so I > don't > > know for sure. > > > > > >> Ping an address in the br-lan network space, and try it again. > >> > >> On Thu, Dec 26, 2019 at 3:42 PM Tomas Kuchta < > >> [email protected]> wrote: > >> > >>> Qualcomm QCA9563 SOC in GL-AR750S package. > >>> > >>> > >>> > >>> On Fri, Dec 27, 2019, 00:12 Mike C. <[email protected]> wrote: > >>> > >>> > I have a theory about why it didn't work on your device. Its what I > >>> > expected would happen and why I didn't suggest what Russell did to > just > >>> > loop one LAN port to another. I think its due to the architecture. > >>> > > >>> > What make and model is your switch/router? > >>> > > >>> > On Thu, Dec 26, 2019, 2:24 PM <[email protected]> wrote: > >>> > > >>> > > It seems that in my case - looping LAN1 with LAN2 and > >>> sending/receiving > >>> > > WAN<-->WLAN3 traffic leads to no visible traffic degradation. That > >>> > > probably mean > >>> > > that I failed to create lan loop. > >>> > > > >>> > > The lights were "kind of" busy on LAN1 <--> LAN2, but the wlan3 and > >>> > > upstream WAN > >>> > > are slow enough to observe any effect on that traffic. > >>> > > > >>> > > I will try to gather together 8+ switches when I get home after the > >>> New > >>> > > Year. > >>> > > With that I may be able to observe some traffic pattern change when > >>> > > crossing > >>> > > switching depth 7. > >>> > > > >>> > > > The router/switch looks this way: > >>> > > > - WAN (eth0) > >>> > > > +- LAN1 (eth1) > >>> > > > +- LAN2 (eth2) > >>> > > > +- WLAN3 (wlan0) > >>> > > > The router is running openWrt. > >>> > > > > >>> > > > >>> > > Tomas > >>> > > > >>> > > On Wed, 2019-12-25 at 09:15 -0800, Mike C. wrote: > >>> > > > > > >>> > > > > I happened to have a netgear FS105 nearby. Plugging in a laptop > >>> to a > >>> > > switch > >>> > > > > port, and plugging a patch cable between two other switch ports > >>> and > >>> > > pinging > >>> > > > > a random ip address from the laptop set off the broadcast > storm. > >>> > > Running > >>> > > > > tcpdump from the laptop showed a bunch of "MPCP, Opcode Pause, > >>> length > >>> > > 46" > >>> > > > > packets. Unplugging the loop, the packets stop immediately. > >>> > > > > > >>> > > > > >>> > > > The reason this works and why I suspect it won't work on the OPs > >>> router > >>> > > is > >>> > > > the Netgear isn't a 802.1D (Spanning Tree Compliant) switch. > Those > >>> > > > multicast packets are flow control packets and would not be > >>> forwarded > >>> > out > >>> > > > all switch ports downstream as per 802.1D they're reserved to be > >>> acted > >>> > > upon > >>> > > > only by the switch. > >>> > > > _______________________________________________ > >>> > > > PLUG mailing list > >>> > > > [email protected] > >>> > > > http://lists.pdxlinux.org/mailman/listinfo/plug > >>> > > _______________________________________________ > >>> > > PLUG mailing list > >>> > > [email protected] > >>> > > http://lists.pdxlinux.org/mailman/listinfo/plug > >>> > > > >>> > _______________________________________________ > >>> > PLUG mailing list > >>> > [email protected] > >>> > http://lists.pdxlinux.org/mailman/listinfo/plug > >>> > > >>> _______________________________________________ > >>> PLUG mailing list > >>> [email protected] > >>> http://lists.pdxlinux.org/mailman/listinfo/plug > >>> > >> > _______________________________________________ > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
