On Apr 19, 2010, at 1:52 PM, William Herrin wrote: > On Mon, Apr 19, 2010 at 1:22 PM, Bryan Fields <[email protected]> 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
