[c-nsp] IOS reliability

[A.L.M.Buxey at lboro.ac.uk]

hi,

there can be the occasional bug or glitch - mainly (in
our experience) due to new types of traffic on the network.
our main downtimes are due to power outage (in excess of
our UPS 6hr capability) and firmware updates.

however, you can help to negate any IOS issue by eg
using dual supervisors in the 6500 platform, or by
using eg s720-10G virtual router architecture. - or
in the 3750 world, by having dual-homed stacks etc.

ie use resiliency to work around any possible IOS/platform
issues (this is true for any chosen network vendor!)

of course, this then comes down to the classic 'if you run
the same version on both boxes they'll get hit by the same
bug' perennial question - I'm always happy to run a slightly
newer version alongside the old trusted....and safeharbor
is always a good option unless you cant use it (eg new a feature
thats not in a safeharbor release!)

alan