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In early January I've updated my Raspberry Owncloud installation from Ownclud 5 to Owncloud 6. So far, everything continues to run smoothly and I noticed some nice improvements. In Owncloud 5 and before, using the web based address book was a bit of a pain as the icons for each address book entry was requested separately and the Raspberry Pi is a bit slow to respond. This has much improved in Owncloud 6, they seem to be all requested and loaded together now, which significantly reduces the load time.

Further, OC 6 introduces thumbnails for files which are generated from their actual content. Sounds nice but on a processing power limited Raspberry Pi it slows things down. Fortunately there's a configuration option to disable thumbnail use. So as far as the address book is concerned OC 6 is faster than it's predecessor and all other functions have not slowed down, despite the massive code increase of OC 6 over OC 5.

What I'd like to see in OC 7 is some optimization for processing power limited systems as I imagine that many people use it on Raspberry Pi's at home as the device is small, cheap and fan-less.

Which makes me wonder: Who of you reading this blog is using Owncloud as well?

So far my main phone I have in use is not LTE capable. While I am in cities I do not mind, the 3G networks in Germany are fast enough so there is not a lot of difference to LTE. But there is one big advantage LTE phones now have in Germany, fast Internet connectivity in the countryside.

Due to spectrum auction rules, network operators had to deploy LTE on 800 MHz in the German countryside first and where only allowed to use this frequency range in cities once rural areas where covered. As a consequence there are a lot of places today with LTE + GSM coverage but without UMTS.

That means that my 2G/3G phone drops down to unusably slow GSM/EDGE in the countryside while my LTE phone in the other pocket continues to enjoy hyperfast connectivity. I've set the 'almost' in brackets in the title because I have a way out: Wi-Fi tethering. Whenever I am in a place with LTE only coverage, Wi-Fi tethering from my LTE phone provides connectivity for my 3G phone. This works very well in practice and the battery of the LTE phone powers the internal Wi-Fi access point for around 8 hours. That's usually more than enough. Agreed, it's a kludge but it works.

Did you know that there's a very easy way to trace the Bluetooth interface between a PC and a Bluetooth dongle on a Linux PC and visualize the result with Wireshark? I didn't and also searching for it on the net only revealed bits and pieces of the puzzle on different web sites. So here's a quick overview of how it all fits together.

Many Linux distributions (such as Ubunutu) ship with the Bluez Bluetooth stack. Part of the stack are a number of very helpful command line tools. Have a look at 'hcitool' (HCI stands for Host Controler Interface, a term defined in the Bluetooth specs) to get general information about connected devices and 'hciconfig' to learn more about the capabilities of the Bluetooth chip in the PC. The most useful tool, however, is 'hcidump' that can be used to trace all Bluetooth messages that are passed between the PC and the Bluetooth chip. On my Ubuntu 12.04 LTS the 'hcidump' tool wasn't installed by default but a simple 'apt-get install bluez-hcidump' does the trick.

'hcidump -X' does some basic level decoding of the messages and outputs the result in real time to the console which is an interesting first step. For more details use the 'hcidump -w filename' command to dump the raw data flow into a file. The file can then be opened in Wireshark without any conversion necessary for full decoding. The two images on the left show how a message looks like in Wireshark that establishes 'HID Interrupt Channel' for a Bluetooth keyboard and how a message looks like that is transmitted to the PC when a key is pressed on the keyboard.

When you use Wireshark make sure you have the latest version as its Bluetooth decoding capabilities have been significantly extended in the past two years. Older versions such as the one included in the Ubuntu 12.04 LTS repository can only partly decode a frame. Compiling and configuring the latest Wireshark version is a bit of a tricky thing though and I'll describe the details of that in a follow up post.

Two years ago, Vodafone Germany reported that they had transported 25 terabytes of data on New Year's Eve 2011 between 8 p.m. and 3 a.m. That was an average throughput of 7.93 Gbit/s as I calculated at the time. For the same period in 2013, Vodafone now has again given out numbers and the comparison is quite interesting. According to this report on Teltarif, the data traffic this time was 66 terabyte, which translates into an average throughput of 21 Gbit/s. An impressive increase perhaps partly also due to their efforts to provide high speed Internet access in underserved rural areas via LTE. In terms of yearly growth rate that's a CAGR (compound anual growth rate) of 62.7%.

Over Christmas, demand for Internet radio streaming must be significantly higher than during other times. Like every year, some of the stations in my favorite list started to get a hick-up on the 23rd of December. This made me wonder what people would say if FM radio today if it had been invented after Internet radio streaming and not long before?

For sure people would say that it's a great idea because it fixes the capacity problem as there is no limit to the number of people who can listen simultaneously. Which is pretty much the only advantage from an everyday perspective, until power fails and the Internet connection drops dead, but an interesting one around Christmas.

But then the number of stations at a location is very limited compared to the thousands of web radio streams one can receive, there are different stations when one is on vacation, they might not play the music one wants to hear, too much talking, too much advertisement, etc. So if we were all used to Internet radio, would a newly invented FM radio actually have a chance if it had to start from scratch?

So far I wasn't exactly impressed by French network operators and their LTE deployments. But it seems 2013 was the year they started to be serious about it. Today I came across current figures of 2G, 3G and LTE deployments of all network operators released by the French regulator and updated monthly. Have a look here for lots of interesting details.

Currently, Bouygues leads with 5.392 active LTE base stations. That compares to around 6.000 LTE base stations currently in operation by Vodafone in Germany (reference). The difference, however, is that most Vodafone LTE sites use the 800 MHz band and thus cover a wider area than those of Bouygues. 3G wise, Bouygues has 10.542 base stations, which is a far lower number than those of Orange and SFR.

Orange, number two in the LTE race in France has 3.879 LTE base stations on air and 17.100 UMTS base stations.

For the numbers of the other operators, have a look at the link above.

At the beginning of 2013, Google announced that they would shut down their Google Reader RSS service in June and so they did. Many were not amused, including me at first, but it was an incentive to make myself independent of yet another one of the few centralized cloud services I used – by setting up my own RSS server at home. After looking around I opted for Selfoss as it looked easy to use and had all the functions I required.

Some things come and go, but Selfoss has stayed. Except for a small hiccup once it keeps doing its job marvelously and even when I'm somewhere without 3G or LTE coverage and have to fall back to GPRS/EDGE, the posts remain perfectly readable as images in the posts are only loaded if a button is pressed.

Thanks Tobias (Zeising), an excellent program I can fully recommend!

Back in May, I've bought a GSM enabled power socket to be able to reset my homecloud from abroad should something become stuck. Since then everything has been extremely stable and I didn't need it once. But then while I was abroad on vacation recently there was a power failure, quite a rare event and the first one this year. I noticed it quite quickly of course because my RSS server stopped responding.

What I found odd was that I didn't get a warning SMS from the GSM power socket as I've tested the functionality in the past and it was working then. There are a number of explanations for this, one of them being that the power outage was a bit more widespread and the GSM base station was also affected. I then sent a status query which was not answered. That had me worried for a bit. But at least I got an sms immediately after power was restored 50 minutes later.

The figure on the left shows how I queried the power status when I noticed that something was wrong and got no answer at first. The following two messages were then received once power was restored together with an answer to my initial status query that was stored in the SMS service center in the network an delievered once power was restored.

Hm, perhaps I should start thinking about buying a USV now. But even if my homecloud at home stays up I wonder where the DSLAM in the street gets its power from… There are some things that are just out of your hands…

Believe it or not but I am still using an 802.11g access point at home because the 802.11n access point that is part of my high end VDSL router at home is just crap. In most cases the 20 Mbit/s I can get out of it through two walls is good enough for my purposes. But my VDLS line gives me 25 Mbit/s so this is hardly a state I can tolerate much longer.

I do have another Wi-Fi access point at home who's 802.11n implementation works a lot better and I get around 70-80 Mbit/s out of it at close range in the 5 GHz band and around 50 Mbit/s through my walls. Next time I manage to be at home for more than just a few days I'll try to port my VPN server configuration from my 802.11g OpenWRT router to this box that also runs on OpenWRT and if it is as stable as my current setup it will be my configuration for the foreseeable future.

Time has moved on, however, and 802.11ac products are already on the market. The recent 1/2014 issue of the German C't computer magazine has an interesting benchmark test with real life scenarios. Speeds measured are between 700 Mbit/s at very close range between a 3×3 MIMO capable 802.11ac access point and a PCI Express card in a PC with three external antennas. But that's rather an exception.

802.11ac USB sticks are only 2×2 MIMO capable and according to the magazine, up to 200 Mbit/s are possible at very close range. In their 20 m + walls scenario the throughput is cut down to 100 Mbit/s. Quite far away from the 700 Mbit/s above but still respectable. In most other combinations that make use of 3×3 MIMO, speeds were in the 350 Mbit/s category at close range (same room but at some distance) to 150-170 Mbit/s in their 20 m + walls scenario.

Interesting numbers to be kept in mind when seeing advertisements of 1300 Mbit/s capable routers (which stands for 3×3 MIMO in the 5 GHz range). Some even advertise their routers as AC1800 because they add the theoretical maximum of 450 Mbit/s of 802.11n in the 2.4 GHz band to the 1300 Mbit/s in the 5 GHz band of 802.11ac. That's what I guess is called creative marketing.

When I first wanted to learn about the ins and outs of Wi-Fi many years ago I discovered what I consider the bible on the topic, '802.11 Wireless Networks – The Definite Guide' by Matthew Gast. It has since held a prime spot in my bookshelf but obviously it is now a bit outdated as it doesn't include information on 802.11n and the current latest and greatest 802.11ac standard. So when I recently wanted to deep dive into 11ac I had a look around on the web and discovered Matthew's '802.11ac survival guide'. After reading it I can very much recommend it because the level of detail and writing style was just what I've been looking for.

While it can be read on it's own if you have some background on how Wi-Fi works, newbies are better advised to first read the general chapters of his original book and then jump into the 11ac survival guide. Both books and his 802.11n survival guide are available as ebooks. If you buy directly from O'Reilly you can download it it in various formats and all of them are DRM free. I'm glad I looked before I bought the DRM protected Kindle edition over at Amazon.

To get a first impression I can also recommend this video on Youtube where he gives a talk about 11ac.