Back in 2014, I came up with a project to use a Raspberry Pi as a Wifi access point in hotels and other places when I travel to connect all my devices to a single Internet connection which can either be over Wifi or over an Ethernet cable. As an added (and optional) bonus, the … Continue reading Update: Secure Hotel Wi-Fi Sharing Over A Single VPN Tunnel For All Your Devices With A Raspberry Pi
I'm a bit nostalgic today because my ISDN telephony days are over. A few days ago, I was “upgraded” to an all-IP line at home because my network operator of choice wants to decommission its ISDN public telephone network, offer VDSL vectoring (instead of fiber connectivity, yeah, right…) and migrate everyone to Voice Over IP. … Continue reading VDSL Speed Upgrade and All-IP – My ISDN Days Are Over
Lots of people I talk to like the idea of having a box at home that can be accessed remotely from notebooks, smartphones and tablets to synchronize private data such as calendar and address book information. They' like it because they'd rather like to have their private data at home than to give it up … Continue reading NAT Is The Main Inhibitor For Self Hosted Cloud Services
IPv4 addresses are slowly running out. As a consequence a number of ADSL and cable network providers have now started to give customers non-routable private IP addresses and perform Network Address Translation (NAT) at their border gateway to the rest of the Internet. As the NAT is performed on their turf they call it Carrier … Continue reading Beware of a Carrier Grade NAT (CGN) Near You
Two companies have made some interesting network usage statistics available recently. In the chart in this post, Verizon states that in December 2008, they transferred around 4.000 terabytes of data through their network. Ed Candy of Three in the UK reported 1.000 terabytes for the same month in his presentation during the Forum Oxford Conference. … Continue reading Is 1.000 Terabytes a Month a Lot?
Unstrung has an interesting pointer to Verizon's first draft spec (v0.9) which details what they want devices to be capable of to allow them on their future LTE network. While they are mainly referring to relevant 3GPP specification documents, there are some nuggets of information in there that took my attention: The 700 MHz band … Continue reading Verizon’s first Draft Specification for LTE Devices
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.
In the fixed line world, the basic Session Initiation Protocol (SIP) has become quite popular for offering voice telephony service. Lots of companies such as Vonage, Siptel and DSL providers are making use of it today. So why are we not using SIP in 3.5G and 4G networks as well? I guess there are both … Continue reading How To Extend SIP For Mobile Networks
In cellular networks, the primary rule for voice telephony is efficiency, efficiency, efficiency. Translated into practice, this means that the mobile device patiently waits till it receives a paging for an incoming call or until the user wants to establish an outgoing call. In the time between, there is complete radio silence, except for occasional … Continue reading Breaking the Radio Silence with VoIP
Ever thought file sharing of others could have an impact on your mobile device’s runtime on a battery charge? If not, read on: For DSL connections I think it is quite the norm rather than the exception that subscribers are assigned a public IP address. In wireless networks things are a bit different. While some … Continue reading How File Sharing Of Others Drains Your Battery