Although networkers might groan at the PHB's "dumb" question in this Dilbert strip, over the years I've had a few students seriously ask "What does happen to packets/frames when they are dropped?".
And I think that it is question worth asking because all the texts that I've read just state that they are "dropped", or even worse, have topology diagrams or flow charts with the dropped packets being dumped into a "bit bucket" (with a picture of said bucket). WTF?
Like depicting electricity as water flowing through pipes, or connected VPN interfaces as communicating through a literal tunnel, or firewalls as brick bbqs/pizza ovens, these analogies/metaphors/whatever are confusing, and in my opinion, technically incorrect.
Ok, not all network technicians/engineers are necessarily electronic or electrical engineers, but how about this; when a packet matches an ACL deny condition, or can't be routed, or a frame FCS doesn't match; the electrical signals representing that PDU are just turned off; buckets are not involved at all. Or perhaps more specifically, the buffer/memory location holding that PDU is overwritten by another PDU, or set to the null value for that system. I hope that makes sense - but, please, no more bit buckets!
http://dilbert.com/strip/2017-08-01
If the zeros are a state of no signal, then aren't they undeletable?
And if the bits are stored on physical media via magnetic induction, then there is potentially a forensic record of them after deletion. The entire electron structure of the hard drive platter has to be reset by some cataclysm for the data to be unrecoverable.
I actually thought it was a good question. The answer to his question is "They are still there, just not referenced anywhere"... which is dangerous if you are relying on them not being there anymore and sell your hard drive to someone who shouldn't have that info.
I am sure there have been MANY people who wished they had asked this question and understood the answer.
This is why I retain hard drives and SIM cards when I recycle my electronic devices.
Yeah, the cartoon is more about data at rest I guess, "saved" ones and zeroes are always there. My context was about data in motion, "dropping packets", etc. Won't anyone think about the dropped packets? ;D
Good post Aubrey!
I would like to know more about this. I wonder if all network devices act the same way in terms of dropping packets? In routers you can route to null0. Is it similar or not related at all? What happens at null0?
Regards,
Tony
Quote from: eaadams on August 03, 2017, 12:12:03 AM
Yeah, the cartoon is more about data at rest I guess, "saved" ones and zeroes are always there. My context was about data in motion, "dropping packets", etc. Won't anyone think about the dropped packets? ;D
We have all our dropped packets boxed up and sent to a shredding service. We had to shop around to find a place that could handle jumbo frames. :D