Are You VoIP Ready? – The Road to China: Content Filtering to the Max

postheadericon Are You VoIP Ready? – The Road to China: Content Filtering to the Max

ChinaNET is managed by the Data Communications Bureau of the Ministry for Posts and Telecommunications, and provides Internet service in all 31 provincial capitals in mainland China. It is one of the two major commercial networks approved by the State Council, the other being ChinaBGN. For this reason, Figure 6 is one of my favorite sites to watch, not because it has great VoIP possibilities – because it does not – but because you can capture the business heart beat of a nation along with the ideology of a government just by viewing this graph over a week s
time. The target site is in a town just south of Shanghai called Hangzhou. The part I find most interesting is that you can tell the moment you hit mainland China (hop 13) because the latency skyrockets from 62ms to 449ms. This is a classic example of Content Filtering  that ChinaNet does in order to keep certain things out of their country. Fortunately, ICMP packets are not one of them, so once we get past the censors, you can see that even within the mainland, there is an overall increase in latency to the final destination – this hints at content filtering within the borders as well. Overall, you can see what the average Chinese Internet user experiences in terms of latency over a weeks time. The graph shows a 7 day cycle and within each day cycle you can see a consistent dip just a little past half way which I found out later was when they – you guessed it – took the equivalent of lunch. This also shows that the basic internal data-transport infrastructure is under a severe load and the chances of VoIP running well WITHIN China are slim if you have to go more than a handful of hops. This might be another reason the Chinese government blocks most of the incoming Internet traffic – the network just could not handle it!
As an aside, when I first started watching this site about a year ago, I was able to see ChinaNet  in the DNSName column. About 7 months ago they removed any identification other than the IP address.
The client originally asked me to see if they could have a telephone connected via VoIP from California to this site and the answer was an emphatic No! . We considered a satellite solution but found out that there were restrictions on this as well. Besides, satellite in general,
has very high latency (too high for decent voice, in my opinion) and is susceptible to bad weather. So as of this article, they are simply resorting to email and regular PSTN connections to communicate.

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