[j-nsp] MX960 Redundant RE problem

[Stefan Fouant]

I was referring more to a bug in hardware... Bad memory, etc.

Stefan Fouant
JNCIE-SEC, JNCIE-SP, JNCIE-ER, JNCI
Technical Trainer, Juniper Networks

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Sent from my iPad

On Feb 15, 2012, at 1:56 PM, Daniel Roesen <dr at cluenet.de> wrote:

> On Wed, Feb 15, 2012 at 12:24:50PM -0500, Stefan Fouant wrote:
>> The cool thing is the Backup RE is actually listening to all the
>> control plane messages coming on fxp1 destined for the Master RE
>> and formulating it's own decisions, running its own Dijkstra,
>> BGP Path Selection, etc. This is a preferred approach as opposed
>> to simply mirroring routing state from the Primary to the Backup
>> is because it eliminates fate sharing where there may be a bug
>> on the Primary RE, we don't want to create a carbon copy of that
>> on the Backup.
> 
> I don't really buy that argument. Running the same code with the same
> algorithm against the same data usually leads to the same results.
> You'll get full bug redundancy - I'd expect RE crashing simultaneously.
> Did NSR protect from any of the recent BGP bugs?
> 
> The advantage I see are less impacting failovers in case of a) hardware
> failures of active RE, or b) data structure corruption happening on both
> REs [same code => same bugs], but eventually leading to a crash of the
> active RE sooner than on the backup RE, or c) race conditions being
> triggered sufficiently differently timing-wise so only active RE
> crashes.
> 
> Am I missing something?
> 
> Best regards,
> Daniel
> 
> -- 
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