Re: Typical additional latency for CGN?

[Andre Tomt <andre-nanog () tomt net>]

On 08. okt. 2012 11:27, Daniel Roesen wrote:
> On Sun, Oct 07, 2012 at 03:18:56PM -0700, Cameron Byrne wrote:
> > On Oct 7, 2012 1:48 PM, "Tom Limoncelli" <tal () whatexit org> wrote:
> > > Have there been studies on how much latency CGN adds to a typical
> > > internet user?   I'd also be interested in anecdotes.
> >
> > Anecdote. Sub-millasecond, with full load. (gigs and gigs) . CGN does not
> > meaningfully add latency. CGN is not enough of a factor to impact happy
> > eyeballs in a way that improves ipv6 use.
>
> Confirmed by my experience.

Latency of the CGN's themselfes are not going to be significant if it is 
properly scaled and configured. Most of the added latency will be in the 
network path to it, depending on how the CGN's are deployed relative to 
the path that particular flow normally would go and how big your network is.

A small detour within a DC is obviously not very noticable for most. 
However if you're skipping peering oppurtunities and such closer to the 
customer when using a big central CGN, that clearly becomes sub-optimal 
in terms of network performance.