Rate of growth on IPv6 not fast enough?

William Herrin bill at herrin.us
Mon Apr 19 15:52:30 CDT 2010

On Mon, Apr 19, 2010 at 1:22 PM, Bryan Fields <Bryan at bryanfields.net> wrote:
> On 4/19/2010 10:14, Patrick Giagnocavo wrote:
>> The eyeball ISPs will find it trivial to NAT should they ever need to do
>> so however, something servers cannot do - you are looking at numbers,
>> not operational considerations.
> LSN is not trivial.
> Here is some unverified calculations I did on the problem of scaling nat.
> Right now I'm using 42 translation entries in my nat table.  Each entry takes
> up 312 bytes of FIB memory, which is ~12.7 Kib of data in the FIB.  Mutiply
> this by 250k users and we have 3,124,237 KiB of FIB entries, or 3.1 GiB.  This
> is not running any PtP programs or really hitting the network, I'm just
> browsing the web and typing this email to you.


Is there some reason we believe we need to scale individual NAT
systems beyond about 1000 users each in order to have the desired
impact on address recapture/reuse? Growing towards 7B people in the
world with, let's say, 4 connected client devices each, grouped 1000
per NAT box requires 7B * 4 / 1K = 28M or 1.7 /8's for the eyeball
networks before structural overhead.

Pushing a carrier NAT process shallow has its own set of complications
(and certainly isn't trivial) but raw scalability doesn't look like
one of the problems.

Bill Herrin

William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

More information about the NANOG mailing list