Unstructured Supplementary Service Data or “USSD” is the stack used in Cellular Networks to offer interactive text based menus and systems to Subscribers. If you remember topping up your mobile phone credit via a text menu on your flip phone, there’s a good chance that was USSD*. For a period, USSD Services provided Sporting Scores, […]
Configuring the Osmocom Serving Gateway Support Node (SGSN) for 2G/3G networks.
A look at the Handover process between Cells / BTSs in GSM using the Osmocom stack.
When setting up the timeslots on the TRX for each BTS on your BSC, you’ll notice you have to set a channel type. So what do these acronyms mean, and how do they affect the performance of the network? GSM channels break down into one of to categories, control channels – used for signalling, and […]
Depending on if you’re wearing a tin foil hat or not, silent SMS and silent calls could be a useful tool to for administering the network or a backdoor put in to track citizenry! Regardless of it’s reasons for existence, let’s take a look at what it actually does, and how we can use it. […]
So far we’ve focused on building a plain “2G” (voice and SMS only) network, which was all consumers expected twenty years ago. As the number of users accessing the internet through DSL, Dial Up & ISDN grew, the idea of getting this data “on the go” became more appealing. TCP/IP was becoming the dominant standard […]
SS7 Basics and Osmo-STP as a Signaling Transfer Point
Setting up ipaccess NanoBTS on Osmocom’s OsmoBSC
How call routing in GSM works and it’s application in the Osmocom suite
So now we’ve covered the basics of what’s involved let’s get some traffic on our network. For starters we’ll need to start each of our network elements and bring up whichever BTS hardware we’re using. In order for our calls to have audio, we’ll need to set a parameter on the Media Gateway. We’ll cover […]
Setting up the Mobile Switching Centre for a GSM network using OsmoMSC.
What the Home Location Register (HLR) does in GSM, how to set it up and configure subscribers.
Connecting our LimeSDR based GSM BTS with OsmoBSC.
Using a LimeSDR as a GSM BTS with Osmocom.
Configuring a GSM Base Station Controller with Osmocom stack.
Setting up a virtual BTS in our BSC with Osmocom.
What’s a BTS and where do they fit into the GSM Network architecture?
Intro to our post series on GSM using the Osmocom stack,
Setting up our GNS3 environment with a bunch of SS7 Nodes
Using Wireshark to sniff communication between your computer and Smart Card / SIM Card