[c-nsp] Stacking 3750X vs diverse 4948E

[Alexander Lim]

Wouw....scary. 
Any clue if Nexus is better than VSS?

Regards,
Alexander Lim

On May 19, 2012, at 8:10 PM, Saku Ytti <saku at ytti.fi> wrote:

> On (2012-05-19 07:47 -0400), Lee wrote:
> 
>> How about VSS?  We're considering it mainly because it would eliminate STP
> 
> There are already horror stories in c-nsp, where software defect has taken
> whole VSS cluster down. STP is very unlikely to do that, as the code is lot
> simpler and lot more mature.
> 
> 
> To me it is clear that main things that cause outages are
> 
> 1. Operator
> 2. Software defect
> 3. Hardware defect
> 
> And there are huge gap between probability of each, i.e. operator is much
> more likely to break the network than software defect, and so forth.
> 
> Yet typically even high budget, high clue, critical importance networks are
> designed with only working around outages caused by 3. Often these efforts
> actually increase probability of 1 and 2. Essentially often the 'well
> design' network has lower MTBF due to the added software complexity.
> 
> Key example here is stateful firewall clusters, which I consistently see
> failing more often than single firewalls.
> When possible, I would separate elements with routing and accept that users
> will see sessions breaking when there is network fault.
> 
> If you keep eye open in press, these examples are on the news all the time,
> where CIO explains that the setup was fully redundant yadayada, it should
> have never failed.
> 
> Latest example I can think of was large outsourcing/integrator losing their
> whole 'redundant' storage setup, causing 5 day outage. Or bit longer ago,
> public sector health care had to resort to dead wood as LAN was down for
> 1.5weeks.
> Both were designed not to fail and neither was designed to workaround (or
> even rapid recover from) software defects.
> 
> -- 
>  ++ytti
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