Rate of growth on IPv6 not fast enough?

Owen DeLong owen at delong.com
Mon Apr 19 16:01:03 CDT 2010


On Apr 19, 2010, at 1:52 PM, William Herrin wrote:

> 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.
> 
> Bryan,
> 
> 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.
> 

The hardware cost of supporting LSN is trivial. The management/maintenance
costs and the customer experience -> dissatisfaction -> support calls -> employee
costs will not be so trivial. 

These facts make me very glad that my networks will NOT be implementing
LSN in any form.

Owen





More information about the NANOG mailing list