Overview Of The Gsm/Gprs System; Gsm Module And Application; Gsm/Gprs Network; Apn - Sony Ericsson GPRS and TCP-IP with the SEM GSM modules Application Note

Using GPRS and TCP/IP stack with SEM GSM modules

2 Overview of the GSM/GPRS system

In Figure 1 a simplified diagram of the overall system is shown, the major
components of these are explained below.

2.1 GSM module and application

This is a GSM module with or without TCP/IP stack on board. If the unit
does not have a TCP/IP stack on board it must be contained on the
application be it microprocessor, PC, etc.

2.2 GSM/GPRS network

This includes the base station through to the APN with all of the
associated IP backbone, etc. The network takes care of the mobility
issues and getting data to the mobile station

2.3 APN

An APN is similar to a URL on the WWW, it is what the unit makes a
GPRS 'call' to. The service provider is able to attach anything to an APN
to create a VPN (Virtual Private Network) i.e. if a security company wanted
its own APN it might have 'security' no one else would then have access
to this, requirements for APN's to be assigned vary between the service
providers.
Most service providers have an internet portal which they connect a DHCP
server to giving access to the internet i.e. Vodafone UK use the APN
'internet' for their portal.

2.4 DHCP server

This is what you negotiate your IP address with and where all of the data
goes through, it effectively acts as your service provider i.e. AOL.

2.5 Internet

The internet is the internet, no explanation should be required.

2.6 Web server

The users web server which has a static IP address or a URL that can be
resolved by a server. This should be running the users application which
can interpret and manipulate the data as required.
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