On Mon, 9 Dec 2013, Stefan wrote:

As $subj may infer, do you guys follow any type of network lifecycle in your environment? If so - what would be some criteria you would consider critical:

You'll probably get lots of different answers to this question depending on where people are working. The lifecycle criteria for an enterprise can be very different from a service provider, .edu, K-12, etc.

- risk reduction while replacing unsupported equipment - security issues associated with OS or appliances not supported

In my $dayjob environment, we generally try to have gear out of produciton before it goes EOS/EOL. For things like closet switches, the main driver is more about keeping current on security issues, since we often have spare hardware to take care of things like chassis failures, etc. For core gear, maintaining a vendor-supported setup is the main driver. Other organizations might also have separate lifecycle plans for core vs. non-core gear. Financially, the amount of capex/opex per device can make a difference. A smaller number of core routers/switches might be expected to have a longer service life (preferably extendable through module upgrades before a forklift replacement is needed) and depreciation schedule than a larger number of smaller access/edge switches, regardless of the expenditure. I generally don't want to forklift core gear more often than about 5-7 years, though business and technical realities might dictate otherwise.

- business / apps demand for capacity or features (e.g. virtualization, SDN, etc.), laid out well in advance to allow for a 3-4-5 yrs plan with a consistent replacement rate of aging equipment

We've been doing this with things like wireless APs - replacing older ones over time in addition to installing new ones to keep up with the demand for coverage.

- increased costs of support for aging equipment, or recertification for vendor support - anything else ... ???

As much as I hate to say it - politics does play a factor in many environments. In the academic world, 'keeping up with the Joneses' has certainly factored into some technology purchasing decisions. In other words: "xyz.edu is deploying $blah. We need to deploy $blah, too."