Just few lines to get pcap files from openbts, at now it’s just a little python script but if i feel not lazy i would directly add method into Openbts sending layer2 packets in a tap interface to grab it in realtime. It currently uses Airprobe’s pcap dissectors so it’s downlink only. Just for fun, here is a screenshot.
The Suscriber Identity Module (aka SIM for shorter) is nothing more but a smartcard with specific files and directories on it. It is defined in GSM 11.11 or ETS 300 977 in the ETSI denomination. As a smartcard, the way to communicate with it goes thru ADPU. You can either use a card reader or ( less in fact ) directly use a gsm modem to issue commands.
The standard command set for GSM modem is defined in “AT Command set for GSM Mobile Equipment (ME) ” (TS 07.07) or just ETS 100 916. It defines a lot of command to interecact with the network or the simcard. As I just want explore the filesystem of my SIM, we’ll just use a command to issue raw adpu directly.
As every walk has his first step, here is the first post on this blog. The title is self explanatory, I’ll focus mainly on the recents development of opensourcing GSM.
The recent releases of Openbts, OpenBSC and the Airprobe projects are openning new area of technological study. More than the political considerations of free the more than widely spreaded GSM technology, it’s just an amazing playground of protocols and devices.
Among the networking parts, there’s also an effort on opening the handset, as demonstrated by Openmoko and Android platform. I’ll sometimes play with these “toys” that are most visible part of the “opensource mobile movment”.
PS: I’m not an engineer of these topics, just another geek hobbyist, so I may omit things or do some mistakes. Sorry in advance.
La Forge @ gnumonks