Category: Uncategorized

The project on Internet connection sharing over cellular networks during meetings I reported on in two previous posts is not quite over yet and I've been working on refining my setup ever since. One thing that often goes wrong in non-optimized hardware setups is the number of devices the built-in DHCP server can give out IP addresses to. In many home grown routers this is actually quite limited, even if the DHCP server range can be specified from .1 to .254. To find out exactly where the limit is, here's a script I've came up with that can be run under Linux and will send 268 requests to the DHCP server, each with a different Ethernet hardware address. Some routers stop giving out IP addresses after 50 leases, some after 60 and only few go to the full range.

#!/bin/bash

for l in {1..99}
do
  sudo ifconfig eth0 down
  sudo ifconfig eth0 hw ether 70:00:00:00:00:$l
  sudo dhclient -r
  sleep 2
  sudo ifconfig eth0 up
  sudo dhclient
  sleep 3
  echo $l " "
  ifconfig | grep "inet addr:192.168."
  ifconfig | grep "HWaddr"
done

for l in {1..99}
do
  sudo ifconfig eth0 down
  sudo ifconfig eth0 hw ether 70:00:00:00:01:$l
  sudo dhclient -r
  sleep 2
  sudo ifconfig eth0 up
  sudo dhclient
  sleep 3
  echo $l " "
  ifconfig | grep "inet addr:192.168."
  ifconfig | grep "HWaddr"
done

for l in {1..70}
do
  sudo ifconfig eth0 down
  sudo ifconfig eth0 hw ether 70:00:00:00:02:$l
  sudo dhclient -r
  sleep 2
  sudo ifconfig eth0 up
  sudo dhclient
  sleep 3
  echo $l " "
  ifconfig | grep "inet addr:192.168."
  ifconfig | grep "HWaddr"
done

Note: Only run this script on your own setup that you can reset afterwards as once the script is through the DHCP server won't give out further IP addresses. Something you don't want to have in a life network…

Here's an interesting link to a post by Troy Hunt with a detailed look on how wasteful some apps are with the amount of data they transfer, how they don't care about the privacy of the user and they transmit data unencrypted, a special treat for anyone using Firesheep in open Wi-Fi networks. Leaves me speechless. For the details head over and be frightened.

In the past months a number of mobile network operators in Europe have switched-on Wideband-AMR in their 3G networks which offers superior sound quality between two WB-AMR mobiles. On paper the difference is tremendous with the frequency range of around 3 kHz extended to 7 kHz, thus transmitting voice and music much clearer than we know today. But how does one perceive the difference in practice?

A hard environment to test this is for example in a train with background noise and recently I had a WB-AMR call while being just in such a place. In short, the experience was incredible for both parties. While on the train I had no difficulties at all to understand the other end and the voice was crystal clear. The positive impression was reinforced when the call dropped due to a coverage hole and when subsequently re-established in the GSM non WB-AMR network I had to make an effort to understand the other side and crank up the volume. I always thought narrow band AMR was quite o.k. but once you've heard wideband it suddenly doesn't sound so good anymore until after a while you ear adapts to it again. 

The title of this post is a bit controversial but I can't help it, when I see the names of companies on some devices today I wonder if my first impression of a new device wouldn't be more positive (or at least different) if I wouldn't see the company name so prominently displayed!? Let me give you some examples:

• Whenever I see an HP notebook these days, I think, "Phew, that's the company that wants to get out of the PC business, this is one of the last" (yes, I know they since have said these plans are off the table). Time perhaps heals wounds.

• Whenever I see "Philips" on a product it immediately goes back into the shelf because I will never buy a Philips product again in my life since the time they refused to give me a replacement for lost in-ear plugs for my noise cancellation headset when I had lost them due to them falling off all the time. A replacement part that perhaps costs one cent they refused to give or sell to me so I could continue using their headset completely destroyed their brand image for me permanently.

• Nokia: So sad, whenever I see Nokia these days I think, "yeah, once a great company, being the leader in the mobile domain, doing open source, being open, creating great devices, etc". But with their 180 degrees turn-around earlier in the year to the ultra-closed Windows Phone OS, the slaughter of Meego and Symbian and their subsequent ultra quick move from market leading company to insignificance makes me feel sad when I see a Nokia logo these days.

• SonyEricsson: Now that Ericsson has sold their stake to Sony and devices are likely to be re-branded soon, anyone with a SonyEricsson phone in their hand will immediately be identified as "out of date".

• HP/Palm/WebOS: Out of business, just like that…

Perhaps you think these thoughts are shallow and one should look behind the company names. But I think the opposite is the case. Companies keep changing their strategies and leave an impression to consumers (or at least to me) that no matter when I buy something from them, the company is going to change in their core values (read: not only their marketing campaign) the second I've swiped my credit card through the reader at the cash register and the device I bought and the ideas it was built on top will not get support from the company in the future and will not see any successors.

Perhaps with the mobile industry evolving at such a quick rate, such twists and turns in very short succession are unavoidable as companies search for ways not to fall behind and gain market share. As a consumer, however, this makes me feel uneasy.

For the second time in so many weeks I've been over in the UK recently and noticed that I am severely restricted in which networks I can select. Not that I can't chose between several networks but in all except one I only got voice service while data seems to have been turned off by my home network operator (read: GPRS service is not allowed). That's quite strange as I haven't seen this anymore since GPRS started many years ago and it was an issue of roaming agreements and links not having been in place.

So what could be the reason this time around? Perhaps, and it's just a guess, this has got something to do with data roaming charges having come down quite a bit in recent years in the EU and network operators who won't give each other reasonable roaming T&Cs now just disable data roaming to prevent making a loss!? After all, the theoretical upper limit in GPRS roaming wholesale prices is still a ridiculous 80 euro cents per megabyte. If you are offering something like to 200 MB roaming data for 10 or 15 Euros to your customer, roaming partners insisting on anything near the wholesale limit are clearly unacceptable.

Let's hope this is only a temporary situation as especially in the UK, with their patchy networks, it's a good thing to be able to use different networks.

Perhaps the following should be nothing special for me having used double digit megabits per second connections over 3G many times before. But still, today, I was using a 3G connection for the first time to stream a full length movie over to my Intel Atom based netbook running Ubuntu Linux, Firefox and Flash for the video playback. I was doing this as I was abroad and wanted to relax in the evening a bit so I decided that I wanted to watch one of my favorite TV shows while in the hotel room. This required the use of a VPN tunnel to a server back home as the streaming was limited to national IP addresses.

The reason why I haven't used 3G networks for streaming in the past is probably that while I am at home, I have no reason for using a 3G network as I have DSL and Wi-Fi i at home. And when traveling, the amount of data I can transfer over a 3G network for a reasonable price doesn't allow streaming full movies, even though being possible from a technical point of view. But if you get 7 Gigabytes for 20 pounds, there's little left to hold you back.

I had only little time when I was recently in London to check O2's UMTS 900 coverage in London but I've been able to catch a few things nevertheless. When taking the train from outside the city to Paddington station I noticed that the UMTS 900 coverage already started in the outskirts of London, well away of the city center. Interesting data point.

While roaming on foot in the city center I was on both the 900 and 2100 Mhz band outside in the streets. When moving further indoors I was sooner or later always falling onto the 900 Mhz layer, as expected, but not before the last little bit of 2100 MHz coverage was gone. In the other direction my mobile jumped back to the 2100 MHz layer as soon as it was found again. In other words, the 2100 MHz layer seems to be preferred at all costs while the 900 MHz carrier is only used in places where 2100 MHz coverage is lost. Not sure if the same applies while the UE is in DCH, however, as all tests were performed in idle. Something to be investigated next time.

Recently I was wondering about the difference in user behavior around SMS depending on whether SMS is used as part of an "all you can eat" contract or paid individually on a message to message basis. When thinking about it I started reflecting on how SMS evolved and how it how it could be perceived in 10 years from now. Here's a bit of past, present and future as it looks to me:

The SMS service has undergone tremendous change since it's first use in the middle of the 1990's. Initially, it was unclear to most people in the industry if users would even have an interest in the service. So, even though SMS was created at the same time as GSM voice service, SMS service was only introduced a few years after the first GSM networks came into operation. For more details on that part of the history on SMS, I can recommend this book.

Other indications that SMS was an uncut gem in the early years are that the first GSM phones did not support SMS at all and some of the first ones that did, such as the Ericsson GH-172 and GH-174 from 1992/93, could only receive SMS messages but not send them. An anecdote that I was recently told by someone who was working on SMS at the time has it that in those years, network operators even had difficulties finding incumbent companies that were developing other GSM network equipment to build them an SMS service center as they saw no market opportunity to such equipment. This matches with the Wikipedia entry on SMS which says in the "early implementation" section that the first SMS message was sent from a PC to a phone via an SMS Service Center by Aldiscon, a company only founded in 1988.

Over the years, SMS has become a phenomenally successful with billions of messages sent single day now and perception has significantly changed. Today, many people still pay per use, i.e. they pay for each message separately. In the US one even pays for incoming SMS messages un less the user is on an unlimited plan. These have also become quite popular in other parts of the world and unlimited plans have completely changed usage behaviors. Instead of one shot messages, unlimited plans invite to use the service as a conversational tool, shooting back messages back and forth and using SMS in a similar way as people have used instant messengers for many years. Obviously, this fuels the grow of the service and also its popularity.

So how will people perceive SMS messaging in 10 years from now? First, who is we? Even today, SMS is used differently in different parts of the world, so I'll concentrate on Europe for now. Perhaps it will look odd at some point that there was something like "pay per SMS message" in the first place. Perhaps, with smartphones and Internet based services becoming the norm rather than the exception, SMS interactive communication will play a diminished role as people resort to instant messengers they already know from their PC and Wi-Fi tablet!?

Another interesting line of thought is that unlike voice calls, SMS is easy to port or be replaced in IP only wireless networks such as LTE, as instant messengers have existed in fixed line networks for many many years and the service is non-real time and non-streaming. In other words, handovers between different radio technologies are no issue at all compared that to the LTE voice call handover issue which is still unsolved in practice.

And a final thought for this post today: Perhaps SMS will become or remain an alternative for people who like privacy and services that don't store and analyze messages for targeted advertising, building social graphs, etc. After all, unlike for web based services for which users don't pay anything and are in fact NOT the customer but only a source of information that can be monetized and on top give up some of their privacy, for the SMS service they might still be that: The customer, who pays for the service of sending and receiving messages, free from other needs of monetization such as selling information gained to third parties.

In April this year Yahoo sold their Delicious online (some would say "cloud") bookmarking service to another company which required a move of the service and the user data from one company to the other. The companies did a sensible thing and only moved the data once the user had opted-in. That is a good thing and since I use Delicious regularly I was made aware of the move and I was able to act accordingly.

Not all users were that lucky though. Recently I got a call for help from a user who had links on Delicious that are quite important but which he suddenly could not access anymore. The problem was, as we soon found out, that he had not used Delicious for quite some time, perhaps half a year. That did not change the importance of the links store there, though. Unfortunately, the data migration period ended this September so the "new" Delicious did not have his account anymore, nor his data, nor did it help in any way to retrieve the data from the old service. Quite a nasty surprise.

So I was asked to the rescue. After some research on the web I found out that there is a way to still get the bookmarks from the old "Delicious" on Yahoo. It involves changing the hosts file on the local computer to redirect calls to delicious.com and a couple of other domains to the Yahoo servers which still seem to sit around. For the details have a look here. With this kludge I was able to export the bookmarks into a local HTML file. Changing the hosts file, something a normal user would never do.

Yet another example why you should

    a) think twice before trusting an online service with your important data

    b) keep a copy of your data locally as well

Fortunately there are some alternatives available to Delicious in the meantime. Firefox Sync for example might be a replacement that is even better than Delicious and is now part of a standard Firefox install. It syncs bookmarks between devices, which is what I used Delicious for and furthermore it encrypts data before sending it to a server in the network (read: "to the cloud") so your data is protected on top of it as well.

Today I found an interesting report on the Ofcom website from back in October 2010 on the potential impact the opening of the 900 MHz band would have for consumers and on competition in the UK. It's very detailed and I have just scratched the surface so far but already found some interesting figures and graphs in it. To reach a conclusion, Ofcom has looked into coverage differences between 2100 and 900 MHz, number of base stations used and much more. In other words, their technical analysis contains details that can answer more questions than what that report was aimed at if you take the time to read it carefully. Note that the text on the web page itself is just the exec summary, the details are contained in the PDF files linked at the bottom of the page.