Have there been studies on how much latency CGN adds to a typical
internet user? I'd also be interested in anecdotes.
I've seen theoretical predictions but by now we should have
measurements from early-world deployments.
Thanks,
Tom
Ancedotally, for users of an e-gadget company's website, cellphone
company's outbound web proxies, internet games company, and
image-intensive home furnishings website, the CGNs delivered content
faster than the main website could, regardless of increasing its
bandwidth. Latency problems with the CGNs were less than the main
websites' latency problems, on the average.
There were days that was not true, and days we had to re-re-re-reset
the CGN contents, and the day the @#$#@$% game programmers screwed up
the CGN calls, but on the whole it was among the least performance
limiting / impeding features of the sites in question.
-george
I think you've confused CGN with CDN.
Huh? I had presumed that CGN was Carrier Grade NAT, not a proxy service. Help me understand.
James R. Cutler
james.cutler@consultant.com
Of all the problems CGN creates, I would think that latency is in the noise
compared to the other issues.
Owen
Or maybe SDN ? So many acronyms to choose from
Sorry, at a conference and not paying enough attention to email. My bad.
-george
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.
I've seen theoretical predictions but by now we should have
measurements from early-world deployments.
Most mobile providers have been doing what is commonly called cgn for 5 to
10 years. CGN is not a new concept or implementation for mobile.
CB
True, but, as we have discussed before, mobile users, especially in the US,
have dramatically lowered expectations of internet access from their mobile
devices vs. what they expect from a household ISP.
We expect half the services we want to be crippled by mobile carriers because
they don't like competition. We file lawsuits when that happens on our
terrestrial connections.
Owen
Speaking of which, has anyone else noticed AT&T mobile is blocking ssh (outgoing 22/tcp) connections? AFAIK, AT&T mobile does CGN. It's puzzling that they'd block outgoing ssh when there have been multiple ssh clients in the Apple app store for years. I used to be able to ssh from my AT&T phone. I found recently, the packets don't get to the server unless I VPN from the phone first (or am on wifi, not relying on AT&T for IP).
You are typically talking microseconds of additional latency for sessions transiting a CGN/LSN type node.
aj
Confirmed by my experience.
Best regards,
Daniel
Thanks for the info!
Tom
Not here, have an SSH session open on my phone on port 22 as we speak. I'm on an android on ATT's 3G network in central indiana, if that matters.
Except now you have to do mediation, since class action lawsuits are now null and void. 
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.
True, but, as we have discussed before, mobile users, especially in the US,
have dramatically lowered expectations of internet access from their mobile
devices vs. what they expect from a household ISP.We expect half the services we want to be crippled by mobile carriers because
they don't like competition. We file lawsuits when that happens on our
terrestrial connections.Owen
Except now you have to do mediation, since class action lawsuits are now null and void.
I'm not convinced that's actually true, however, even if you ignore the idea of a class-action,
the more effective approach is a vast fleet of small-claims cases. Corporations are generally
much better prepared and resourced to deal with mediation and/or class-actions. An
influx of a huge number of small-claims actions in courts all over the place, OTOH, costs
very little resources on the plaintiff side while having a much larger impact on the
corporation, even if the corporation prevails in every case.
Owen
Should we include the time spent talking to the help desk trying to resolve
double-NAT'ing issues in the latency?
Have there been studies on how much latency CGN adds to a typical
internet user? I'd also be interested in anecdotes.
Should we include the time spent talking to the help desk trying to resolve
double-NAT'ing issues in the latency?
That's downtime to address the brokenness, or loss of availability
1% after you count time users waste trying to navigate large
carriers' confusing telephone IVR mazes designed to obscure access to
helpdesk, hold time, time waiting for callbacks, and finally,
non-resolution of double-NAT issue without user paying extra for
non-NAT IP; which is all different from network latency, and of much
greater impact than a latency increase <0.1ms.
That's a different sort of latency, and from what I've heard, it's often measured in days rather than fractional seconds.