# R6 Information Elements

Information Elements (IEs) are included in all GTP control message packets, and provide information about GTP tunnels, such as creation, modification, deletion, and status. ScreenOS supports IEs consistent with 3GPP Release 6. If you are running an earlier release, or have contractual agreements with operators running earlier releases of 3GPP, you can reduce network overhead by restricting control messages containing unsupported IEs.

To configure the security device to screen the following R6 IEs:

Radio Access Technology (RAT)

### RAT Configuration

Currently, the SGSN IP address is used to distinguish between 3rd Generation Wireless Mobile Communication Technology (3G) systems and 2nd Generation Wireless Mobile Communication Technology (2G) systems. With the introduction of combined 2G/3G SGSNs, however, this is no longer possible. By default, the security device passes R6 RAT IEs.

To configure the security device to drop R6 RAT IEs, do the following:

1. Enter the RAT IE name string in the Value Match box.

2. Select Action Drop.

3. Click Apply.

Routing Area Identity (RAI) and User Location Information (ULI)

### RAI and ULI Configuration

Some countries restrict subscriber access to certain types of network content. To comply with these regulatory demands, network operators need to be able to police subscriber's requested content before allowing a content download. ScreenOS gives network operators the ability to do this based on the Routing Area Identity (RAI) and User Location Information (ULI) IEs. Also, due to the lack of these attributes in current 3GPP Call Detail Record (CDR) formats and realtime charging interfaces, billing and charging systems are required to look up SGSN IP addresses to determine roaming partners for settlement and end-user charging. ScreenOS gives network operators the ability screen control messages based on RAI and ULI. By default, the security device passes GTP messages containg R6 RAI and ULI IEs.

To configure the security device to drop R6 RAI IEs, do the following:

1. Enter the RAI IE name string in the Value Match box.

2. Select Action Drop.

3. Click Apply.

To configure the security device to drop R6 ULI IEs, do the following:

1. Enter the ULI IE name string in the Value Match box.

2. Select Action Drop.

3. Click Apply.

International Mobile Equipment Identity-Software Version (IMEI-SV)

### IMEI-SV Configuration

The International Mobile Equipment Identity-Software Version (IMEI-SV) information element provides ways to adapt content to the terminal type and client application whenever a proxy server for this purpose is not present. This information element is also useful in reports generated from the GGSN, AAA and or WAP GW. The GTP-aware security device supports the RAT, RAI, ULI, APN Restriction and IMEI-SV in GTP attributes to avoid treatment or categorization as unambiguous traffic, which can be harmful to GPRS traffic or GPRS roaming traffic. These attributes are included in the set of useful filter attributes to block specific GPRS traffic and or GPRS roaming traffic. By default, the security device passes GTP messages containing R6 IMEI-SV EIs.

To configure the security device to drop GTP messages containing R6 IMEI-SV IEs, do the following:

1. Enter the IMEI-SV IE name string in the Value Match box.

2. Select Action Drop.

3. Click Apply.