Remotely Connecting To Your Home Services

For those of you who have been following my blog entries on femtos, home services and DLNA in the past couple of days, here's a link to a previous blog entry on Ericsson's ideas on how one could connect back to home services while not being at home.

I wished that the currently defined set of home services could be extended to other things such as a centralized calendar, notes, address book, etc. as I am one of the few people who would like to have this data stored at home rather than in the cloud. But I guess the current DLNA initiative is more about multimedia content than personal information.

Telstra to Upgrate to HSPA+

A tip from a reader brought me to this article on Telstra in Australia saying that they intend to upgrade their 3.5G network in Australia first to 21 MBit/s in 2009 and later on to 42 MBit/s. The step to 21 MBit/s seems logical. According to the 3GPP standards, that's an upgrade to 64QAM modulation. If they have the latest base stations from Ericsson, they might be able to do this without a hardware upgrade.

Concerning the 42 MBit/s, that sounds like the 28 MBit/s one gets with MIMO plus 64QAM modulation on top. When I last had a look at the standards document referenced above, there was not yet a terminal class for this maximum speed.

A note of caution: Such speeds can only be reached under very special circumstances, i.e. no other subscribers in the cell and the base station antenna very close by.

DLNA – Nokia N95 Streaming Multimedia Content over Wifi

Here's a little follow up on my previous thoughts on how mobile devices could interact with devices in your home network. This video of Nokia shows how the uPNP DLNA compatible Nokia N95 is used as a Mobile Digital Media Server (M-DMS) by a game console and a TV screen to get pictures and music. Quite impressive!

First ‘One Tunnel’ Network Sighted in the Wild

While LTE is in development, loads in 3G networks are increasing and network operators are looking for ways to reduce their costs. One such move seems to be moving to a 'One Tunnel' architecture in which the user data packets bypass one of the packet core nodes, the SGSN.

Instead of tunneling the packets between the mobile device and the Internet through the base station, the RNC, the SGSN and the GGSN, this approach directly connects the RNC and the GGSN. As a consequence, fewer resources are required on the SGSN since it doesn't have to 're-package' the frames from one tunnel into another (hence the feature's name 'One Tunnel'). For details see this blog entry.

Nokia Siemens Networks now reports that network operator '3' in Austria is their first customer for the One Tunnel feature in this podcast that can be found here. I can imagine that they are quite keen to use the feature since Austria is a very competitive market and SIM cards and USB data sticks for 3G Internet access can be bought in every supermarket for next to nothing.

HSDPA Alongside A CS Voice Call

Back a year ago I noticed that an incoming circuit-switched voice call during a 3.5G HSDPA packet-switched data session forced the packet connection to go back to 64 kbit/s dedicated bearer while the call was ongoing. After the call the bearer was upgraded to 384 kbit/s but was only put back on the High Speed Shared Channels once the download was finished. Looks like the software on the network side has advanced a bit in the meantime as I recently noticed that even during a phone call an ongoing download continued at HSDPA speeds. Very nice!

Note: The test a year earlier was performed in the German Vodafone network while my latest observation is from the Orange France network. The RAN vendors might not necessarily be the same and it's even likely that they are not.

Smartphones: Units, Revenue, Profits

Recently, David Wood shared a couple of interesting numbers on his blog on the importance and relation of smartphones compared to 'ordinary' phones. In his post he says that while smartphones only account for 10-15% of sales units, the sales revenue is between 20-25% and profits may even exceed 40%.

So far, I wondered if big mobile manufacturers are mainly working on smarthphones as a way to secure their future by developing new features on these platforms and then work on finding ways of implementing them on cheapter platforms. These numbers, however, suggest that even for their running business, smartphones have a major impact on the bottom line, despite the small unit numbers.

Femtocells and Connected Home Services

Last week I met Thierry Samama in Paris, who is looking after ip.access' pico- and femtocell business in France to discuss a bit about the wireless industry and, of course, about femto cells. I asked him what he thinks about accessing devices at home via a 3G device directly via the femtocell instead of going through an operators core network. It was good to hear that ip.access is actually already working on this and he pointed me to this video in which they demo their connected home services capabilities. The video doesn't give many technical details but the applications shown are just what I had in mind concerning interaction between 3G handsets and devices at home such as a media server, TV set, etc.

The Key To The User's Heart

To me, accessing the home network via the femtocell holds the key for users actually wanting a femtocell at home. An alternative are of course dual mode devices with a Wifi interface. However, without pre-configuration of those devices by the mobile operator, who could of course do that if they wanted to, most people will have difficulties configuring the device to make use of them in the home network. Definitely an advantage for femtocells since no configuration of the mobile is required.

The video doesn't say exactly how local access works and how the applications on the Windows Mobile driven devices access devices and in the home network. UPNP perhaps? Nokia has already made strides in this direction with UPNP, which is part of S60 and Nseries phones which come equipped with a Wifi interface.

Femto In A Bundle

So I think femtos packaged together in a single box with Wifi and DSL/cable access sold by a converged fixed/mobile operator will best sell in a bundle which also includes mobile devices, pre-configured applications on them that can access resources in the home network, a media server at home and some IPTV. So instead of getting a subscription for a DSL line which includes IPTV and fixed line telephony offered these days in many countries, I could very well imagine that the femto that allows local access forms the bridge to the wireless world and removes the need for that extra telephone line. Others like Nokia are likely to take the Wifi/UPNP approach and it will be interesting to see how the different approaches compete with each other.

For more info on Femtos, connected home services, handover, autoconfiguration etc. have a look at ip.access' home page, they've got some good ressources there.

DPI and eMail blocking

The more I use wireless Internet access, the more things I stumble over how network operators use Deep Packet Inspaction (DPI) to 'shape' use to their liking. After having been blind charged for eMail in the past and having seen reports of network operators modifying email signaling exchanges to prevent encryption from kicking in, this time I am blocked from receiving eMails.

My current mobile Internet access via a prepaid SIM from Orange in France contains unlimited Internet access and 10 MB (yes, a mere TEN!) to access my email via POP3 or IMAP. I have no idea how I could have stepped over this limit since I am only days in the monthly subscription cycle and all emails downloaded to the mobile are capped at 15 kb. However, one morning I could no longer poll my mailboxes.

Profimail on my N95 crashes as soon as I attempt to access my mailboxes and the Nokia email client reports that the connection to my email provider has failed. Over a Wifi link, both programs can access my email just fine. So I turned to Wireshark to check what is going on and saw that when connected via Orange, the TCP connection requests on the port numbers reserved for POP3 and IMAP are not discarded, as I would have expected it, but immediately answered with a RST (Reset) packet. Note that this packet must have been originated by the DPI device. Looks like Profimail doesn't handle rejected connections gracefully and decides to exit.

Apart from the technical glitch that this provokes, I don't think Orange is doing itself a favor by just blocking incoming eMail. They should have at least sent me an SMS saying that my monthly transmission volume for email has been exceeded and that I shouldn't be surprised that it has stopped working. They could even use it as an upsell opportunity to open the email gate again for an additional charge after sending a text message with a certain content. I'd be happy to pay even if I don't know how I stepped over the limit. Without this option I am now stuck to the mobile webmail interface of my mailboxes while in France, which is a bit uncomfortable. The average user, however, will just be turned off by such a behavior and will probably turn away from the service entierly.

Also, they should offer a web interface that shows me when an how I have spent 10MB on emails in just a couple of days. I am really puzzled.

18% of Voice Calls Handled in Swedish 3G Networks Now

Two more facts caught my eye in the 2007 market report of the Swedish Telecommunication Authority:

3G Network use for Voice Calls

18% of mobile voice calls (3 billion minutes) where handled by 3G networks, while the remaining 82% must consequently have been handled by GSM networks. Not a huge number yet but it shows the subscriber base is slowly moving to 3G handsets.

Decreasing overall use of Circuit Switched Telephony

The second number is even more astounding: The number of fixed and mobile telephone minutes decreased from 60.000 million minutes in 2001 to just 45.000 million minutes in 2007. The major factor for this is that dialup internet connectivity are being replaced by DSL. Another factor, but minor is the decreasing use of voice telephony due to the adoption of other forms of communications. Mobile minutes are increasing which means fixed line minutes are falling fast.

My SIP Calls Are Proxied – And I Don’t Like it

I recently wanted to check out a couple of things concerning the SIP client on my Nokia phone when I stumbled over something I was not prepared for. In theory, the voice path between two SIP devices is supposed to be direct, i.e. one device sends the speech packets directly to the other device. In my case however, the SIP INVITE messages were always changed by the SIP Proxy to route the speech path packets through a media proxy in the network. I was quite perplexed.

Why would my SIP provider do that? Is someone spying on me? Is the government taping into my calls? Yes, maybe I am a bit paranoid, but this is not the way it is supposed to be. I ran a lot of different scenarios to see if the behavior changed like using different accounts, different SIP clients and different network configurations. However, no matter what I did, the INVITE message sent out and the INVITE message received on the other end were different and the speech path was relayed via a media proxy of my provider.

The Explanation

In the end, I contacted my SIP provider and asked them what was going on, not really expecting that I would get a qualified response. To my big surprise, I got a competent answer from one of the engineers explaining that they've had lots of trouble with Network Address Translation (NAT) in the past and have thus decided to route any call through one of their servers as soon as a NAT was detected in the transmission path. Calls from SIP clients without NAT in the way, he said, would not be routed that way. O.k. I thought, then let's test that, I believe it when I see it.

It's not that simple to set something up without a NAT in the IPv4 address space these days, specifically not behind DSL lines. However, with some VPN tunnels I finally managed to get a setup in which both SIP clients were not NATed. And sure enough, no media proxy in the speech path anymore. O.k. great, so I am not spied on, what a relief.

Open Questions

However, a couple of questions remain. Why all this fuss about "Simple Traversal of UDP over NATs" (STUN) when in the end the SIP proxy detects the NAT situation and deploys a countermeasure without the help of STUN? Is it really that unreliable? Also, sending practically all SIP to SIP calls through a media proxy must require a lot of resources in terms of bandwidth and computing power from my SIP provider for which he is not reimbursed since SIP to SIP calls are free of charge.

Lawful Intercept

This brings me to lawful interception of VoIP calls. Depending on the country you live in there are more or less strict laws in place these days that require that VoIP providers must be able to target all calls going through their system, which obviously includes direct SIP to SIP calls. The only way to do that, without the target knowing that somebody is listening in, is to route all calls through a media proxy. Bitcom, the German association representing the Internet industry is pushing very hard against this, saying that it is not practicable to proxy every call. Seems that that is not quite in line with what is already done anyway to get around NAT issues. A lot of hot air for nothing?

Summary

One way or the other, I don't like my calls being sent through a media proxy no matter for what reason. It's time IPv6 is finally marching in to rid us of NATs. If by the time law mandates commercial providers to media proxying all calls it might be time for my own Asterisk SIP server at home so at least "internal" calls are not proxied. Also, such a solution would provide for security and encryption of the call, both not supported by my SIP provider today.

But then, for those who really want to be sure nobody is listening in, they have to buy a pair of these or these.