On Jun 6, 2013, at 5:02 PM, John Mann <[email protected]> wrote: > Hi, > > On 7 June 2013 08:41, Rajiv Asati (rajiva) <[email protected]> wrote: > Hi Dan, > > > and so on. I am surprised you conclude that "500 seems ok" when such a > > limit would interfere with your network use on those days. > > I based that statement ("...seems ok,") on the very fact that the number of > times the NAT utilization exceeded 500 mappings (equating to 500 ports, in my > setup) in the sample period (~2 months) was relatively quite low. So, if the > NAT device was limited to only 500 mappings, then the experience would have > been ok for 99% of the time and degraded 1% of the time. This is an important > consideration, IMO. > > For ex, in the last 2 weeks, the number of times NAT mappings exceeded 500 > were: > > June 3 - 1 time > May 29 - 1 time > May 28 - 3 times > May 26 - 1 time > May 23 - 1 time > May 22 - 2 times > May 21 - 3 times > > I think a more-interesting statistic would be "how many connection setups > would have failed". > But I don't think you can measure that just by polling concurrent connections > at specific times. > It might take e.g. netflow exporting and analysis ... > > However "number of concurrent connections that couldn't have been setup" > would be useful in gauging the impact > e.g. on May 29 there was one spike of 734 concurrent connections, then report > that as 234 potential failures. > > Of course, 1000 ports (resulting in 1000+ mappings) would have been more than > enough to accommodate the times when the mappings exceeded 500, but stayed > within 1000 (except once). > > > > What is the maximum number of mappings supported by your NAPT device? > > Some residential-class NATs have a limit of 1024 mappings. > > Is that a combined limit of TCP and UDP and ICMP, or independent?
The study at http://eggert.org/papers/2010-imc-hgw-study.pdf only analyzed TCP bindings. -d > > My NAPT device seemingly can use upto 64K ports. :) > > Cheers, > Rajiv > > > > -----Original Message----- > > From: Dan Wing (dwing) > > Sent: Thursday, June 06, 2013 11:43 AM > > To: Rajiv Asati (rajiva) > > Cc: [email protected]; Softwires-wg list ([email protected]); > > [email protected]; Erik Kline ([email protected]) > > Subject: Re: [BEHAVE] Home NAPT44 - How many ports? > > > > > > On Jun 5, 2013, at 6:14 AM, Rajiv Asati (rajiva) <[email protected]> wrote: > > > > > Some of you may recall our discussion (during the last IETF) around "how > > many TCP/UDP ports are enough with NAPT44" per home, as ISPs move into > > A+P paradigm. ~500, ~1000, ~3000??? > > > > > > Well, I started monitoring my home router and plotting the NAPT44 port > > utilization on a minute-by-minute basis. You may find it here - > > http://www.employees.org/~rajiva > > > > > > In short, port range of 500 seems ok, though 1000 would be more than > > enough for my home. > > > > I see several spikes in your data over 500 ports. During those times, > > applications would be unable to function (unable to get a port). April > > 29/30 > > is a long time where that occurs very visibly, but there are shorter spikes > > elsewhere such as on April 17 and April 18. If you had only 500 ports on > > those days, creating a new TCP mapping would have been impossible, > > impacting ability to send or receive email, order books from Amazon.com, > > and so on. I am surprised you conclude that "500 seems ok" when such a > > limit would interfere with your network use on those days. > > > > What is the maximum number of mappings supported by your NAPT device? > > Some residential-class NATs have a limit of 1024 mappings. > > > > -d > > > > > Suffice to say, this is just a sample representation, since the port > > utilization would vary home to home, based on number of active devices, > > type of applications, the degree of simultaneous device or application > > usage etc. > > > > > > If any of you are doing similar monitoring, then please share. > > > > > > Cheers, > > > Rajiv > > > > > > PS: Thanks to Erik Kline, who explained (with sufficient details) how to > > > use > > google charting for my data. And thanks to Xun Wang & Shaoshuai Dai for > > helping me out significantly. > > > > > > PS: My home has 3-4 active devices. > > > _______________________________________________ > > > Behave mailing list > > > [email protected] > > > https://www.ietf.org/mailman/listinfo/behave > > _______________________________________________ > v6ops mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/v6ops >
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