Whenever a Mobile Station (MS) needs some kind of service from the
network, a series of messages are sent across different links in order
to facilitate this service. Some examples include Location Update, IMSI
Attach, IMSI Detach, and placing and receiving calls. These tutorials
illustrate some of the different tasks that are needed to facilitate
service and the messages that are exchanged in order to complete those
tasks. Choose one of the events from the menu above to view how it
Authentication and encryption are not considered an "event"
since it is required every time the MS requests access to the network.
Authentication and encryption is covered in detail here.
*Note: For all GSM events, only the signaling messages for the Air (Um)
Interface are specified on this website. In the future, messages for
all interfaces will be included on the website.
Authentication & Encryption