[c-nsp] RAM thing

Lukas Tribus luky-37 at hotmail.com
Mon Feb 17 17:47:11 EST 2014


> I recently ran into (likely) memory issue which caused sporadic corruption in
> IP header, had it occurred anywhere else than IP headers or were we IPv6 only,
> it would have been invisible to me. Is there 98.7% probability that some kit
> in my network is currently corrupting packets outside header?

I find that hard to believe. All routers, even old ISR G1s have ECC to detect
such failures. Depending on the platform and configuration, those boxes may
crash/failover due to parity errors, right?

Also on hardware based platforms I doubt the RAM ever sees a packet.

I don't have the impression that silent corruption of traffic is what this
is about. RAMs fail all the time, but our boxes do detect it (or at least
crash). Of course, hardware malfunctions can lead to packet corruption, but
thats uncommon compared to RAM failure I believe (otherwise we would see a
*lot* of payload corruption on the Internet which is really not the case).

> While I agree more info on failure rate would be helpful, it's worth
> noting that the chance of failure has not suddenly gone up, just because
> Cisco has announced it - this issue has been extant since 2005.
> So nothing has changed except we know about it. For anyone who assumed
> devices could fail at any time, this isn't *that* worrying. For anyone
> who assumed devices would run forever, this should be a wake-up call -
> it was never true, and will likely never be so ;o)

I couldn't agree more.



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