Recently, I've been in Shanghai for a conference and as it was my first time in China, I was looking quite forward to see how GSM, UMTS, Internet connectivity, speed and access of resources at home through VPN tunnels would work from there.
On the cellular front, GSM and UMTS are working fine for me, but a few times when establishing a PDP context, no data would flow afterwards. After tearing it down and reestablishing it, everything was fine. Data transfer speeds don't seem to be very snappy back to Europe, but it doesn't matter much as prices are so prohibitive anyway, that I only use connectivity for downloading emails without attachments and for web browsing by using Opera Mini which does a fair amount of data compression.
Encryption and Tunneling
I am using mandatory encryption for sending (SMTP) and receiving (POP3) emails via servers back in Europe and both over cellular (with a German SIM) and the Internet at the hotel that works just fine. In other words, that's not blocked in any way. Also, my company VPN to Germany works just fine over the hotel Wi-Fi. After all of this working so well I was a bit surprised that the VPN product I use on my private PC would not connect to any gateway around the world, it seems to be blocked. A quick chat with the online support of the company, however, gave me a workaround within 5 minutes and I managed to get a VPN tunnel working to a gateway in the US.
Speed, speed, speed
When accessing servers in China from Europe I always have the impression that things are rather slow. Perhaps, I always thought, this was due to generally limited connectivity to Europe? But when bringing the Internet connectivity for the conference online I got a steady 10 MBit/s in the downlink direction and 10 MBit/s in the uplink direction to servers back in the US and Europe. So, no, it could not have been the transit links that were previously slow. Another thing demystified.