Author: Martin

Earlier this week, the EU parliament reported that they have reached an agreement with the European council on the final piece of the puzzle for the abolishment of roaming charges in the EU by mid-June this year: Wholesale prices. This is good news and it’s interesting to take a closer look on the compromise that was reached.

Continue reading EU Roaming – The Final Word On Wholesale Caps?

One big advantage of ‘alternative’ voice solutions such as Skype and many others is the use of much better voice codecs that make a huge difference in practice. Many mobile network operator voice systems have been upgraded over the years to support Wideband-AMR. In practice I get a lot of WB-AMR calls while people use the same mobile network as I do. The rate of adaption is quite good as people quite frequently get themselves new devices that support the feature. The fun stops, however, as soon as I call someone on another network. For years, nobody thought it a priority to add gateways that support wideband codecs. A bit of a shame.

Many fixed line phone connections have also been converted to IP over the years and usually also support a wideband codec. The problem here is that in order to enjoy the speech quality of a wideband codec, not only the line but also the fixed line phone has to be upgraded.

Continue reading The Uptake of Wideband Speech Codecs in Fixed Line Networks Is… Glacial

Recently, I’ve been in Seoul again for a week. When I was there back in 2013 it was straight forward to buy a SIM card at the airport so I thought I’d do it again this time around. While selling prepaid SIM cards was something of a novelty then it seems to have become a lucrative business as there were a plethora of options this time. One has to be careful however, as not all SIM cards one can get at the airport can be used straight away.

Continue reading Getting a Prepaid SIM in Korea – Dos and Don’ts

In the previous post I’ve had a closer at, among other things, the spectrum use of ADSL vs. ADSL2+. The change in uplink and downlink throughput when the line was updated was quite significant. The main difference was made by using the lower spectrum that was previously used for voice telephony as additional spectrum for the DSL uplink and by doubling spectrum use from 1.1 to 2.2 MHz, i.e. from 256 tones (carriers) to 512. Let’s have a look at how ADSL2+ spectrum use compares with VDSL2, which I have at my home.

Continue reading VDSL2 Spectrum Use

A friend of mine lives in the countryside at the very fringe of DSL coverage. While a decade ago a 3 Mbit/s DSL line with a 450 kbit/s uplink could still be considered sufficient, things have changed quite a bit these days. Several computers and smartphones are now connected to his network which makes using voice over IP applications such as Skype difficult as especially the uplink is immediately affected when someone else uploads data. Don’t even think about video telephony with a reasonable video quality. Running Skype and desktop sharing simultaneously is also next to impossible, downloading software updates takes ages and streaming HD video has become impossible in many cases.

Recently, however, my friend’s DSL line with bundled analog telephony was migrated to all-IP, i.e. voice telephony now also runs over IP. The only benefit I could see when this was announced was that voice quality would be upgraded to Wideband-AMR so I made sure he had a compatible phone by the time of the switch. In addition, I noticed that at the same time, the telephone company switched the line from ADSL to ADSL2+ which brought a huge improvement to up- and downlink speeds. I’m glad I took a number of screenshots of the DSL connection information before and after the switch as they reveal some very interesting details.

Continue reading ASDL2+ More Than Doubles Speed At The Digital Fringe

In many countries around the world, network operators are sharing parts of their radio access networks. In many cases the country they operate in is split up into different parts and each network operator exclusively installs the network infrastructure for both. Obviously this reduces cost but also denies companies that are part of the agreement to differentiate themselves in the one thing that matters: Speed and capacity. Continue reading Network Sharing Pains In The UK

Recently I set up a new web server on a Raspberry Pi at home to securely run a new web application and to properly isolate it from my other servers. One new thing I wanted to try out was setting-up a Let’s Encrypt certificate for https access and to learn how the tools work to automatically install and update the certificate.

It turned out that it’s not very difficult to do it, just a bit different from the standard installation method described on the Let’s Encrypt web site for Debian based system. Also I noticed that one should ensure that http digest authentication configured in ‘.htaccess’ files for some directories still works as intended once Let’s Encrypt is set-up, as it didn’t in my case.

Continue reading Let’s Encrypt On A Raspberry Pi Web Server

A few weeks ago I wrote about a magazine article I found in which micro-SD card speeds were evaluated. In the article, amazing speeds were mentioned that I could not reach with my USB2 Micro-SD adapters. So I went out and bought a small USB3 reader. I turned out that while read and write speeds improved, they were nowhere near those in the article, despite using the same Micro-SD cards. So I bought a ‘Ugreen USB 3.0 SD-card reader‘ with a built-in USB-3 hub that got good reviews for its read and write performance.

Continue reading In Pursuit of Micro SD-Card Speeds – Part 2

Back in 2016, I’ve written quite a number of blog posts about how to set up a server at home that is reachable over IPv6. Here’s a link to the summary. Over time one forgets some of the details so I recently couldn’t remember anymore if I’ve just opened my IPv6 firewall for single ports to the IPv6 Interface ID of my server or if I had given a ‘carte blanche’. No worries, as after all, who can find me in 128 bits of IPv6 entropy? But then I watched this talk at the recent 33C3 conference and I got worried enough to check my setup like real quick…

Continue reading 33C3: IPv6 at Home – Make Sure Your IPv6 Firewall Works As Intended!