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Thanks to an international 3G subscription I have long ago given up searching for Wifi hotspots at the locations I travel to. Instead, as the Sprint guys put it, the 3G network is following me wherever I go. I see it the other way round. Wherever I go, the network is already there. While I have always managed so far to find good 3G or EDGE connectivity, there are some pitfalls which I wouldn’t have thought existed anymore three years after the commercial launch of the first UMTS networks. Here are some strange but true examples:

France: For a month or two now, Orange, the mobile operator that allows me to roam to its 3G network, seems to have a new software version running on their UMTS network in Paris. Since then, my almost brand new Nokia N70 behaves strangely and has trouble establishing a dedicated bearer during a packet session after some time of inactivity. This results in very long delays in the order of 10 seconds or more when I click on a link after some time of network inactivity. The only remedy is to trick the network into letting me have a dedicated channel continuously by constantly sending pings to a host on the network. While this helps for notebook use, I can’t use this trick while web browsing via the mobile phone. So I prefer using Organe’s EDGE network by forcing the mobile into GSM only mode. In other parts of the country things work flawlessly. This is probably due to the fact that Orange uses different UMTS access vendors in different parts of the country: Alcatel in Paris, Nortel and Nokia in other parts of the country. Well done, Orange!

Germany: Here, I have a greater choice of UMTS roaming partners: T-Mobile, E-Plus and O2. The first two work flawlessly with my Nokia N70. O2 also works well if the mobile can find the UMTS network. Sometimes, however, the mobile just refuses to see the network, especially after the mobile has lost coverage for some time like for example if I have parked the car in an underground garage. Switching the phone on or off does not change anything. Even a manual network search, which shows that the 3G network is available, does not force the mobile back into O2’s UMTS network. The only action that helps sometimes is to go back to the place where the phone has no GSM or UMTS coverage of O2’s network for a minute. It’s a repeatable phenomenon and I’ve only seen it in Germany and only with O2. Also, I have to restart the phone much more often than in other networks, about once per day, as after some time I can’t connect to the Internet anymore.

Austria: Again, I have several roaming partners for UMTS: T-Mobile, A1 and One. In the A1 network I have detected the strangest problem yet. With both my Nokia N70 and my somewhat older Sony Ericsson V800 I have problems to send data from the notebook to the network. An analysis with Wireshark, a network tracing tool, revealed that the network has problems with large IP packets in uplink direction. At first I thought it was a specific mobile problem in combination with the network components used in the A1 network. However, as two completely different phones have the same problem it seems to be a general network issue. What helps is to reduce the Maximum Transfer Size (MTU) of the notebook for dial up connections. After changing the MTU size to 480 bytes as described in this Microsoft bulletin, things worked a lot better. But quite frankly, I prefer using ONE’s network where things work as they should. Just in case I ever end up in a part of Austria where ONE’s network is not available, I still have my MTU jocker ready.

All of this is very strange as both of my UMTS phones are widely used in these countries. But I think it shows that 3G interoperability is still not where it should be. Nevertheless, things are not as bad as they might seem after describing these three cases for the following reasons: Even in the countries described above I have found at least one network in which things work flawlessly with my mobiles. In addition, here’s a list of countries where I didn’t encounter problems, at least not in the networks I used: Switzerland (GPRS and EDGE), Spain, Italy, Belgium (EDGE), The Netherlands, U.K. and Portugal.

Another week, another Carnival of the Mobilists. This week, the CoM is hosted by Daniel Taylor over at the Mobile Enterprise Weblog. So for the best writing on mobile topics of the past week head over to his site and enjoy!

Maybe it’s because we are used to getting patches to our PC every month or so now that the following story has not seen wide spread attention so far: Intel admits Centrino chipset driver issues: These allow attackers to send malformed wireless lan frames to insert and execute malicious code (read viruses).

This is scary for two reasons:

Firstly, no user interaction is required. This means that a user doesn’t even have to browse to a malicious webpage to get infected. It’s enough to have your WLAN card activated. Airports and conferences might become nice playgrounds for past time hackers and self replicating viri once an exploit for this hits the net.

Secondly, the fixes have to be installed manually. There is no auto update functionality like for example for Microsoft Windows patches which are downloaded and installed by the operating system once available. I’ve downloaded and installed the patch for a notebook with a Centrino 2200BG card. A 129 MB (MEGABYTE!) download. Incredible! At least it installed o.k. and the driver was updated. Then I downloaded the patch for another notebook which has a Centrino 2100 chipset. A refreshingly short 13 MB download… When executing the file it installed an update for the helper program but failed to update the driver for the chipset. The program showed no sign that the driver, where the real problem sits, was not updated. Perfect, the average user will never notice that… So I manually installed the driver update from the hardware settings. To make the day perfect, many notebook vendors have chosen to write their own wireless lan configuration utilities that interface with the driver in some way. Of course they could be broken if you install the driver. Take a look at F-Secure’s blog. Once an exploit for this hits the wild, it’s going to be big.

Speculation: Could the same scenario happen in the cellular world, too? In theory I could imagine this happening in the cellular world as well. Imagine that somebody finds a bug in the IP stack of mobile devices or in the mobile browser that could be exploited in the same way. Downloading fixes on such devices is still a procedure most device manufacturers have yet to come to terms with. For the moment, though, I think such a scenario is unlikely. Unlike in the PC world with a dominance of Windows and Intel Centrino chipsets the mobile space is much more diverse which would prevent or at least slow down such a scenario. Nokia with their Series 60 phones might have a good approach to this. No buffer overflows possible as per OS design and software and patches can be pushed to a device Over the Air (OTA) starting with S60 3rd edition.

Finally, fresh out of the virtual press, the Carnival of the Mobilists has appeared this week on Howard Rheingold’s Smart Mobs blog. Written by Judy Breck, the Carnival contains an overview of the best blog entries on mobile topics published by mobile enthusiasts all over the world in the previous week. So head over and enjoy!

Today I read a post on Teltarif, a German website, that FON has partnered with a German DSL reseller to offer bundles for prospective Foneros. For those of you who haven’t heard of FON before, they are attempting to build the largest Wifi Hotspot network in the world with the help of private enthusiasts.

I like the idea of bundling FON with a DSL offer, as I think becoming a Fonero must be as easy as possible in order to be successful. At closer inspection, however, the bundle falls short of the "Buy our product and we will deliver a box which you just have to plug into your phone socket at home to become a hotspot". Instead, the offer only bundles a FON account, a Fon Wifi access point and a DSL data subscription provided by Interroute Germany.

What’s missing is the DSL line subscription and a DSL modem which you have to get separately. Apart from being too complicated for the average user who’s thinking about becoming a Fonero because he lives downtown or near a hotel, the hardware lineup is also not reflecting todays DSL landscape. While it was common to have a separate DSL modem and a separate Wifi router a couple of years ago, integrated Wifi routers + DSL modems are the norm these days.

Great first step FON, but now it’s time to put your software on an integrated Wifi router / DSL modem and find a reseller who is willing to do the final step and sell both the DSL data subscription and the DSL line in one package.

As a frequent traveler, I’m amazed that each country seems to have it’s oddities when it comes to mobile carriers. In some countries, mobile voice and mobile data is very cheap while in others just accross the border, the world looks quite different. Debi Jones of MobileJones.com and Mediaslaves has been nice enough to do the first in a series of podcasts discussing the state of wireless in different countries. Debi lives in California, so the US mobile landscape is the center of our discussions:

Part 1:

• Coexistence of GSM and CDMA in the US
• HSDPA deployment
• Closed down CDMA handsets
• The Nokia vs. Qualcomm battle
• The Korean CDMA/UMTS situation
• Price of wireless data

Podcast, MP3, 26 mins, 12 MB

Part 2:

• Muni Wifi and combination of Cellular and Wifi Data plans
• Wireless traveling in the US
• A hotspot detector (check it out at CanaryWireless.com)
• Wireless Instant Messaging, Yahoo Go!, Skype and Trillian
• Verizon’s Walled Garden
• Mobile phone multitasking on Nokia N-Series phones
• Mobile phone design

Podcast, MP3, 28 mins, 13 MB

Sometimes I find it really strange that a large part of wireless networks is everything but wireless. The only part which is really "wireless" is the radio channel between the user and the cell tower. Behind the base station data and voice is transferred over copper or fiber cables, or microwave links in some cases.

Kevin has come up with an interesting whitepaper on the evolution of the transmission network behind the base stations which is required to adapt the networks to the increasing demand for mobile data. Among many other things the following figures were quite interesting to me, especially when combined with an earlier post of mine on data usage of a mobile PC user and potential revenue generated per base station:

• Cost of Running the Network: The percentage for running the network from the total operational expenditure (OPEX) is around 30%. On the other hand, 43% of the money goes to Marketing, Sales and Administration… (see figure 2 in the whitepaper). I wonder if (and where) the salaries of the various top executives (CEO, CTO, CMO,…) are included in the OPEX!? 😉

• Backhaul Line Rental: On page 4, the whitepaper says that the line rental for a 2 MBit/s E-1 link used for most UMTS base stations today is about € 250.- per month. This amounts to about 1/3 of the 30% spent from the total OPEX on network operation.

• Cost for Technical Personnel: The costs for technical personnel to run the network amounts to another third of the network operation costs. This is 10% of the overall OPEX. Not very much compared to the 43% for Marketing, Sales and Administration…

Kevin Evans has put a post on his blog on HSDPA backhaul over ADSL. At first, it seems like a pretty good idea he says but has some second thoughts:

Kevin says Internet Service Providers (ISP) would probably be less than happy to connect HSDPA ADSL links to their  backbone. I agree! Cells where HSDPA is used heavily will pretty much use most of the bandwidth of an ADSL link for a considerable time per day. Consequently, such links would substantially increase the load of the ISPs ADSL backbone.

He then goes on to say that the alternative for mobile operators is to do their own ADSL backhauling. He thinks this is also not a good idea due to having to build an overlay network for backhauling next to the E-1s currently used for real time voice traffic. But why is it such a bad idea for operators to put their own ‘mini’ DSLAMs in central offices and have a little fiber there for backhauling? There is cost whatever you do, E-1, microwave, etc. so why not ADSL?

Some operators might have already decided to do this (speculation on my part). O2 Germany for example has said that they want to become an integrated fixed- and mobile telecommunication company, providing both high speed fixed line Internet access via DSL and high speed mobile Internet access via HSDPA. If they decide to build their own ADSL network, they can use it for both purposes.

As an alternative, Kevin suggests to use Ethernet for carrying both real time voice traffic and non real time background and streaming traffic generated by web browsing, podcast downloads, etc. But what about the distance you can cover with commercial Ethernet equipment today over phone cables?

When I first read about HSDPA over ADSL backhaul it immediately made sense to me due to the fact that ADSL has become a cheap technology to bridge larger distances than what is possible with other technologies. Have new long distance Ethernet technologies caught up in the meantime?

Whatever operators decide, I hope they decide quickly as HSDPA over 2 MBit/s E-1s is not going to make people happy.

Silently, my fellow co-worker Pierre Lescuyer has updated his excellent book on UMTS called "Réseaux 3G" (3G networks) and the 3rd edition is now available in French. The new edition contains among other additions new chapters on HSDPA, HSUPA, IMS and MMS. Previous editions are also available in English and German.

Very well done, Pierre, congratulations!