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Re: [IETF] Re: IPv6 deployment [was Re: Recent Internet governance events]

2013-11-22 16:13:21

On Nov 22, 2013, at 6:11 PM, Ted Lemon <ted(_dot_)lemon(_at_)nominum(_dot_)com> 
wrote:

On Nov 22, 2013, at 2:29 PM, Phillip Hallam-Baker 
<hallam(_at_)gmail(_dot_)com> wrote:
They will scale fine just like the dialup pools have scaled fine.

Dialup pools are stateless.   CGNs are stateful.   They do not scale the same 
way.   This is not to say that you _can't_ scale CGNs—

So, something that has always confused me abut the CGN deployment discussions 
and scaling is the number of customers (victims?!) that people want to put 
behind an IP…

If you are an operating ISP with e.g a /18 you can have ~16,000 customers[0]. 
Great, you are still growing, and want to add another 10,000 users, good for 
you.
For some reason at this point many ISPs start talking about putting on the 
order of 100s of users behind an IP, then the discussion turns into port 
starvation and scaling and such… 


What's wrong with putting 2 users behind each IP? Are you really planning on 
doubling your size *before* significant advances in v6 deployment and CGN 
scaling come about? Yes? Ok, so put 4 users behind one IP (note, I did not say 
"device") -- are you really planning on quadrupling in the next few years? And 
if so, are you hiring? :-P

Seriously, I don't get the "If we deploy CGN's we have to cram as many users 
behind one address as possible…" bit -- can anyone enlighten me?

I've run some big NATs (for example, for AOL's corporate network) and yes it 
sucks, but you can minimize your (and your customer's) pain by overloading as 
little as possible…. 


it's just easier to scale stateless-core NATs.   I say this based on zero 
operational experience, of course... :)

Sure, fair 'nuff, no argument here….

W
[0]: Yes, yes, handwave, handwave, packing issues, infrastructure space, etc. 
Been there, run a network… Skipping all that for easy of discussion. 


--
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species, but in a world where pit props could crack without warning and pockets 
of fire damp could suddenly explode they'd seen the need for gods as the sort 
of supernatural equivalent of a hard hat. Besides, when you hit your thumb with 
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random-fluctuations-in-the-space-time-continuum!" or "Aaargh, 
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