Techblog

Using 3G as a backup Internet connection in Shanghai

2009 July 17

Since January 2008 I’ve been based out of Shanghai, China. Despite being based out of this part of the world, many of my clients are European companies. Thanks to Internet and modern communication facilities, like Voice over IP, teleconferencing, and of course email and chat, working with customers over large distances in general works out really well. (I’ll probably publish another article on my general experiences later.)

One major pain for all digital workers in China with international projects, however, is the Internet speed over here. DSL lines are available everywhere, with nominal download speeds of 2MBit/sec or so, and upgrades of up to 100MBit/sec have been announced. The problem is the fact that actual results vary a lot, especially when accessing servers outside of China.

One of the reasons, of course, is the Great Firewall of China - mainly a means for censoring content that is considered to be illegal, subversive or obscene by the Chinese government. While it is easy to get around this censorship (through a VPN or proxy, for example), not surprisingly, the filtering costs a lot of performance.

On the other hand, the Great Firewall does not seem to be the only limiting factor. If you use Internet from different locations, like home and office, as well as different parts of the city, and a different daytimes, you notice very different throughputs.

So a couple of days ago, I decided to get a second channel that I can use anywhere in Shanghai in case the main connection is not as responsive as I need it to be: I bought a China Unicom 3G UMTS USB stick. For 150 RMB a month (around 16 EUR) you get a 3 GB package.

(Notice that China Mobile, that I use as my main mobile operator e.g. on my iPhone, offers similar packages, but only provides GPRS/EDGE speed. The 3G service that they are building up is not compatible with international UMTS equipment.)

After doing some sample tests, China Unicom 3G seems to be a good alternative, when data gets stuck on the main DSL connection!

I used speedtest.net to compare the speed when accessing a server in Frankfurt, Germany from Shanghai. In this sample, I got around 1.45 MBit/s download, 350ms ping and only 0.09 MBit/s upload using the normal China Telecom DSL line in my home office (without VPN). Compare that with the 2.39 MBit/s, 1.03 MBit/s and 469ms ping time using the China Unicom 3G connection! Results are similiar when tunneling through UK-based or US-based VPNs over the same connections.

Here are the detailed results:

China Telecom DSL, Shanghai to Frankfurt, no VPN:
1.45Mb/s DL, 0.09 Mb/s UL, 350ms ping

China Unicom 3G UMTS, Shanghai to Frankfurt, no VPN:
2.39Mb/s DL, 1.03 Mb/s UL, 469ms ping

China Telecom DSL, Shanghai to Frankfurt, via Los Angeles based VPN:
1.49 Mb/s DL, 0.12 Mb/s UL, 369ms ping

China Unicom 3G UMTS, Shanghai to Frankfurt, via Los Angeles based VPN:
2.51 Mb/s DL, 1.55 Mb/s UL, 470ms ping

China Telecom DSL, Shanghai to Frankfurt, via UK based VPN:
1.55 Mb/s DL, 0.13 Mb/s UL, 323ms ping

China Unicom 3G UMTS, Shanghai to Frankfurt, via UK based VPN:
I lost the exact numbers, but results were very similiar to Los Angeles based VPN.