This seems entirely plausible given that DWDM amplifiers and lasers being a
complex analog system, they need OOB to align.
--
Eric
> On 31 Dec 2018, at 16:06, Saku Ytti wrote:
>
> Hey Steve,
>
> I will continue to speculate, as that's all we have.
>
>> 1. Are you telling me that several line cards failed in multiple cities in
>> the same way at the same time? Don't think so unless the same software
>> fault was propagated to all of them. If the problem was that they needed to
>> be reset, couldn't that be accomplished by simply reseating them?
>
> L2 DCN/OOB, whole network shares single broadcast domain
>
>> 2. Do we believe that an OOB management card was able to generate so much
>> traffic as to bring down the optical switching? Very doubtful which means
>> that the systems were actually broken due to trying to PROCESS the "invalid
>> frames". Seems like very poor control plane management if the system is
>> attempting to process invalid data and bringing down the forwarding plane.
>
> L2 loop. You will kill your JNPR/CSCO with enough trash on MGMT ETH.
> However I can be argued that optical network should fail up in absence
> of control-plane, IP network has to fail down.
>
>> 3. In the cited document it was stated that the offending packet did not
>> have source or destination information. If so, how did it get propagated
>> throughout the network?
>
> BPDU
>
>> My guess at the time and my current opinion (which has no real factual
>> basis, just years of experience) is that a bad software package was
>> propagated through their network.
>
> Lot of possible reasons, I choose to believe what they've communicated
> is what the writer of the communication thought that happened, but as
> they likely are not SME it's broken radio communication. BCAST storm
> on L2 DCN would plausibly fit the very ambiguous reason offered and is
> something people actually are doing.
>
> --
> ++ytti