job screening question

Owen DeLong owen at
Fri Jul 6 02:37:02 UTC 2012

On Jul 5, 2012, at 6:28 PM, Jon Lewis wrote:

> On Thu, 5 Jul 2012, William Herrin wrote:
>> On Thu, Jul 5, 2012 at 8:22 PM, Owen DeLong <owen at> wrote:
>>> I would use questions such as the following:
>>> 1.      How many end-sites can be numbered from a single /32.
>>>                (Correct answers: IPv4 - 1, IPv6 - 65,536)
>> IPv6 - 16,777,216 to 268,435,456 :p

I'd accept those if I was willing to send the candidate to rational IPv6 networking re-education camp.
If I expected the candidate to be able to do real work immediately, I would require the correct answer
as specified above.

Assigning a /56 to an end-site is bad juju. Assigning a /60 is pure useless evil.

>>> 5.      What is the reason for the 100m distance limit within an ethernet collision domain?
>> What's an ethernet collision domain? Seriously, when was the last time
>> you dealt with a half duplex ethernet?
> You've never (much less recently) seen a customer misconfigure their end of an ethernet handoff such that you end up with duplex mismatch? Granted, in that case, distance is irrelevant...but it is half half-duplex ethernet :)

Either way, the collision domain itself is irrelevant to the question at hand... The important thing is to find out that the candidate understands what an ethernet pre-amble is and why it is important.


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