Category: Uncategorized

On my desktop PC I proud myself with only having to reboot perhaps once a week. While I consider this as a sign of operating system stability I recently noticed that I could not remember when I last rebooted my Android based smartphone. Even though I use a lot of apps such as the web browser, Google maps for navigation, the Kindle App and FB-Reader for ebooks, K-9 for email, the weather app, train table lookup app, etc. etc. it took over 1000 hours to finally come to a point when a reboot was necessary. That's over 40 days the OS was running non-stop. A new personal record as my previous phones usually rebooted in some sort of self-defense mechanism every now and then.

It doesn't happen often but it does happen: Just when you are on the other side of the world, your cloud services at home hangs up. The DSL router looses sync, the VPN gateway has decided to go belly up or one of the servers stops cooperating. So what can be done? If one could only perform a reset…

In the past I've used a power socket with a timer to cut power once during the night to reset everything. Crude but effective with the slight disadvantage that in the worst case I have to wait till the next morning for my services to come back. Another slight disadvantage is that late at night local time is not necessarily a convenient time in another timezone for the VPN service to go down for a couple of minutes during local daytime. So I was looking for a more sophisticated solution and have found a cool "out of band" way to reset my network at home, a GSM Power Socket.

In Germany the GSM power socket is sold under the brand name of "GSM-One", for example via Amazon for 89 euros. To switch power on or off a simple SMS with a command code inside is used. The power socket then returns a status message to confirm the command. Very cool. Even cooler is the the SMS alert message when a power outage occurs and an SMS status report once power returns. Very nice, this puts me back in the drivers seat again no matter where I am.

In other countries, the device is sold under different brand names. In the UK for example it Sells as "Lindy GSM Power socket" for a shocking 142 UK pounds. For those not familiar with currency exchange rates between pound and euro, it's around 1.1 at the moment. Quite a hefty surcharge to order it in the UK…

The previous post on the Raspberry Pi as a GSM gateway has made me think of what other uses such a setup could have. A bit of a thorn in my privacy and open source loving heart is Skype. Closed source and controlled by Microsoft is about as far away from privacy and open source as one could imagine. But it works and I use it quite often and especially with its video calling option I didn't see real alternatives. That is until now…

Perhaps the following setup should do the trick:

• A Raspberry Pi hosted at home
• Asterisk on the Pi, 25 Mbit/s down and 5 Mbit/s offers ample capacity for voice calls
• Ekiga for SIP telephony between two PCs. According to the Ekiga page, HD voice and HD video streaming are supported.

So on paper this looks pretty cool as it would cover my application of making video calls between two PCs, one usually in my home network and the other somewhere on the Internet. With the SIP telephony server running in my own network and the voice and video stream running peer to peer it's about as private and open source as it gets. But how well does it work in practice? There are lots of unknowns beginning on the PCs and how well Ekiga runs on them down to the network layer and how Ekiga can handle the NATs in between. With a spare RasPi available I wonder how long I can resist giving it a try!? 🙂

I've been running my ownCloud server on a Raspberry Pi for quite some time now and to say I am enthusiastic about it is rather an understatement. The Raspberry's versatility is incredible and I've recently come across another application that could come in quite handy in the future: Running Asterisk PBX on a RasPi and using it as a GSM Gateway.

Here's a post over at the Carrier-Connect blog that describes such a setup to forward calls over IP for a person's mobile number of country A to the person's mobile number of country B with the help of two Raspberry Pis and two 3G/GSM data sticks that are also circuit switched voice capable. And to make the Asterisk setup as painless as possible there's even ready to go Raspberry Debian (Raspbian) image and documentation available here. Amazing!

From what one reads on the web, OwnCloud seems to have become quite popular. While I have two small Owncloud servers of my own at home I had yet to see someone else use it, too. And to my surprise it happend faster than I thought.

When I recently passed by the desk of one of my co-workers I noticed the familiar ownCloud design in his web browser. It turned out that it was the ownCloud of a company that wanted to share a number of documents with him without using a public storage provider.

Very nice so now I know for a fact now I am not alone. While Dropbox or similar services would have spared the company the effort to set up their own server it looks like privacy and confidentiality were ranked higher than convenience.

How nice!

Here's a link to an interesting post over at Telegeography titled "International bandwidth demand is centralizing". The figure at the top of the post nicely visualizes the two key messages:

Not surprisingly lit (used) capacity of undersea cables continues to increased at a staggering pace, around 50% year over year. Between Europe and the US, for example, capacity of around 12 Tbit/s was added in the past 5 years. Terabits…

The second point of the figure is that unlike in previous years, bandwidth additions have been pretty much equal across the globe and are no longer focused just between Europe and the US. I would have thought differently with the majority of cloud and video streaming services being operated by US companies. But perhaps not so surprising at all with companies such as Akamai making sure content is not streamed across undersea cables but from a server as close to the user as possible.

Remember Delicious? Once upon a time I used Delicious quite a lot to store bookmarks I didn't want to have in the bookmark menu of my web browser and which, in all likelihood, I would never need again anyway. But one never knows and there are pages which are not easily to be found with a search engine and every once in a while I was glad I could go back to my "bookmarks dump".

Then in 2011 Delicious as we knew it faded away and morphed into something different and I had to re-import the bookmarks into my web browser which was an adventure all by itself. This worked quite well for some time but for some reason the bookmark search algorithm in Firefox was really slow and I had to delete the better part of my bookmark pile. But now I'm back in the game again with the ownCloud bookmark application.

After all my posts on ownCloud in the last couple of months you must either have one of your own by now or be weary of my ramblings on it. But I can't help it, I just like it and it proves more and more useful every day for sharing documents as well as calendar and address book synchronization. With a little bookmarklet in the browser I can now save bookmarks again in the cloud with a single click and search through them when needed in ownClouds browser based GUI.

Just like in the good old Delicious days but with privacy added as the data is stored on my server at home. Perfect!

IPv4 addresses are slowly running out. As a consequence a number of ADSL and cable network providers have now started to give customers non-routable private IP addresses and perform Network Address Translation (NAT) at their border gateway to the rest of the Internet. As the NAT is performed on their turf they call it Carrier Grade NAT or CGN.

While being state of the art in wireless networks for many years now CGNs certainly have one advantage, they shield mobile devices from unsolicited packets from the Internet and hence keep power consumption down. Unfortunately there is a major disadvantage as well which is especially troublesome for fixed line connections at home: Your network is not reachable anymore for incoming connection requests.

Many people won't notice but as soon as you are running your own services such as an Owncloud server you are out of luck. Verizon, for example, is switchng to CGNs and private IP addresses and some German cable operators have started doing it as well. While Verizon at least offers a way to opt it seems that others are less flexible. Too bad when you signed a one year contract… I wouldn't be surprised if some will even start asking for extra money for a public IP address. Market economy, scarce resources, you get the idea…

IPv6 is obviously the solution but networks, devices and VPN gateways supporting it are still scarce. Therefore make sure before changing your home network provider that you will really get a public IP address!

The more I use my Owncloud server at home for exchanging files with others and keeping my calender and address book synchronized between various devices without relinquishing control (see here and here), the more I have come to like cloud services. I also use my Owncloud server at home while on the move via HSPA and LTE and when doing so, the major bottleneck is the uplink data rate.

For calendar and address book synchronization and also for downloading files from the cloud, an HSPA connection is fully sufficient. When uploading larger files to the cloud, however, HSPA becomes quite limiting. This is due to the limited uplink speeds of HSPA networks today, typically between 1 and 2 Mbit/s. How times and perceptions change… Not too long ago such speeds were considered amazingly fast. Not that this is an inherently wireless issue as ADSL uplinks are often even slower, most not even exceeding a megabit per second.

LTE is refreshingly different in this regard. When reception is good, I can easily achieve speeds way beyond the 5 Mbit/s my home VPN is limited due to the processing power of my VPN gateway. And for files exceeding just a few megabytes this makes a real difference.

So while for the most part I regard LTE as a capacity extension to server more simultaneous users rather than being there for offering higher download speeds, the uplink speed is the real differentiator for me!

Cloud services seem to be dying at an ever increasing rate these days. A year or two things started for me with Delicious abandoning its popular bookmark service, followed by the announcement of Google to discontinue their RSS reader at some point this year. And now Wetpaint has decided to block the Prepaid Wireless Internet Access Wiki that they hosted on their servers for many years without giving any reasons or warning. Ouch.

Over the years Wetpaint seems to have changed its focus several times and today the hosted Wikis seem to be little more than an unloved project on the side for them. Already over the last year I have noticed that the server the Prepaid Wireless Internet Wiki is hosted on has become slower and slower to the point of being of little use. That should have been a warning sign and an incentive to think about moving the content. But I didn't…

Now the Wiki is blocked and there is no way to export the pages. Support on the Wetpaint Central site for such issues also seems to be zero and all my inquiries have been left unanswered so far. And so once more the lesson is: Never trust a cloud service, your data could be gone in the blink of an eye without any warning.

Too bad, the Wiki has proven to be quite useful over the years.