> > You seem to be implying that you don't believe/can't see the GFW
No, that's not what I meant. I thought mandatory content filtering at the border means traffic throttling at the border, deliberately or accidentally rate-limiting the traffic, now I think he was referring to GFW and the side effect of deep packet inspection. In fact, we designed a small experiment to locate the hops with GFW presence, and then try to match them with the bottleneck hops. We found only in 34.45% of the cases, the GFW hops match the bottleneck hops. Best, Pengxiong Zhu Department of Computer Science and Engineering University of California, Riverside On Mon, Mar 2, 2020 at 1:13 PM Matt Corallo <na...@as397444.net> wrote: > > find out direct evidence of mandatory content filtering at the border > > You seem to be implying that you don't believe/can't see the GFW, which > seems surprising. I've personally had issues with traffic crossing it > getting RST'd (luckily I was fortunate enough to cross through a GFW > instance which was easy to avoid with a simple iptables DROP), but its > also one of the most well-studied bits of opaque internet censorship > gear in the world. I'm not sure how you could possibly miss it. > > Matt > > On 3/2/20 2:55 PM, Pengxiong Zhu wrote: > > Yes, we agree. The poor transnational Internet performance effectively > > puts any foreign business that does not have a physical presence (i.e., > > servers) in China at a disadvantage. > > The challenge is to find out direct evidence to prove mandatory content > > filtering at the border, if the government is actually doing it. > > > > Best, > > Pengxiong Zhu > > Department of Computer Science and Engineering > > University of California, Riverside > > > > > > On Mon, Mar 2, 2020 at 8:38 AM Matt Corallo <na...@as397444.net > > <mailto:na...@as397444.net>> wrote: > > > > It also gives local competitors a leg up by helping domestic apps > > perform better simply by being hosted domestically (or making > > foreign players host inside China). > > > >> On Mar 2, 2020, at 11:27, Ben Cannon <b...@6by7.net > >> <mailto:b...@6by7.net>> wrote: > >> > >> > >> It’s the Government doing mandatory content filtering at the > >> border. Their hardware is either deliberately or accidentally > >> poor-performing. > >> > >> I believe providing limited and throttled external connectivity > >> may be deliberate; think of how that curtails for one thing; > >> streaming video? > >> > >> -Ben. > >> > >> -Ben Cannon > >> CEO 6x7 Networks & 6x7 Telecom, LLC > >> b...@6by7.net <mailto:b...@6by7.net> > >> > >> > >> > >>> On Mar 1, 2020, at 9:00 PM, Pengxiong Zhu <pzhu...@ucr.edu > >>> <mailto:pzhu...@ucr.edu>> wrote: > >>> > >>> Hi all, > >>> > >>> We are a group of researchers at University of California, > >>> Riverside who have been working on measuring the transnational > >>> network performance (and have previously asked questions on the > >>> mailing list). Our work has now led to a publication in > >>> Sigmetrics 2020 and we are eager to share some > >>> interesting findings. > >>> > >>> We find China's transnational networks have extremely poor > >>> performance when accessing foreign sites, where the throughput is > >>> often persistently > >>> low (e.g., for the majority of the daytime). Compared to other > >>> countries we measured including both developed and developing, > >>> China's transnational network performance is among the worst > >>> (comparable and even worse than some African countries). > >>> > >>> Measuring from more than 400 pairs of mainland China and foreign > >>> nodes over more than 53 days, our result shows when data > >>> transferring from foreign nodes to China, 79% of measured > >>> connections has throughput lower than the 1Mbps, sometimes it is > >>> even much lower. The slow speed occurs only during certain times > >>> and forms a diurnal pattern that resembles congestion > >>> (irrespective of network protocol and content), please see the > >>> following figure. The diurnal pattern is fairly stable, 80% to > >>> 95% of the transnational connections have a less than 3 hours > >>> standard deviation of the slowdown hours each day over the entire > >>> duration. However, the speed rises up from 1Mbps to 4Mbps in > >>> about half an hour. > >>> > >>> > >>> We are able to confirm that high packet loss rates and delays are > >>> incurred in the foreign-to-China direction only. Moreover, the > >>> end-to-end loss rate could rise up to 40% during the slow period, > >>> with ~15% on average. > >>> > >>> There are a few things noteworthy regarding the phenomenon. First > >>> of all, all traffic types are treated equally, HTTP(S), VPN, > >>> etc., which means it is discriminating or differentiating any > >>> specific kinds of traffic. Second, we found for 71% of > >>> connections, the bottleneck is located inside China (the second > >>> hop after entering China or further), which means that it is > >>> mostly unrelated to the transnational link itself (e.g., > >>> submarine cable). Yet we never observed any such domestic traffic > >>> slowdowns within China. > >>> Assuming this is due to congestion, it is unclear why the > >>> infrastructures within China that handles transnational traffic > >>> is not even capable to handle the capacity of transnational > >>> links, e.g., submarine cable, which maybe the most expensive > >>> investment themselves. > >>> > >>> Here is the link to our paper: > >>> https://www.cs.ucr.edu/~zhiyunq/pub/sigmetrics20_slowdown.pdf > >>> > >>> We appreciate any comments or feedback. > >>> -- > >>> > >>> Best, > >>> Pengxiong Zhu > >>> Department of Computer Science and Engineering > >>> University of California, Riverside > >> >
