Cisco Cisco Packet Data Gateway (PDG)
• SNMP MIB Enhancements
• System and Platform Enhancements
RTLLI Management for 2G M2M Devices
Feature Description
Fixed Random TLLI (RTLLI) Management for 2G M2M devices is intended to expand the operator's control
of TLLI (temporary logical link identifier) in the following scenario:
of TLLI (temporary logical link identifier) in the following scenario:
When multiple M2M devices attempt PS Attaches, with the same fixed RTLLI coming from different NSEIs
(network service entity identifier), the SGSN cannot distinguish between the devices. The SGSN functions
as if the first device bearing an RTLLI is no longer attached and begins to communicate with the next device
using that same RTLLI. With multiple M2M devices attempting attaches - all with the same RTLLI - the
result is TLLI collision and dropped calls.
(network service entity identifier), the SGSN cannot distinguish between the devices. The SGSN functions
as if the first device bearing an RTLLI is no longer attached and begins to communicate with the next device
using that same RTLLI. With multiple M2M devices attempting attaches - all with the same RTLLI - the
result is TLLI collision and dropped calls.
How It Works
This feature deals with Attach problems due to simultaneous IMSI attaches, all with the same fixed RTLLI.
Beginning with Release 16.3, it became possible to configure the SGSN to discard/drop Attach Request
messages received from an MS with an RTLLI already in use on the SGSN by adding validation of the NSEI.
Attach gets processed if the attach is coming from a different NSEI. This functionality is disabled by default.
messages received from an MS with an RTLLI already in use on the SGSN by adding validation of the NSEI.
Attach gets processed if the attach is coming from a different NSEI. This functionality is disabled by default.
Beginning with Release 19.3, to further reduce jumbling of authentication vectors across subscribers, the
Fixed Random TLLI Handling mechanism extends the functionality noted above. A new verification table
has been added to the GbMgr. The table maintains a list of TLLI + NSEI and if an incoming Attach Request
includes a TLLI + NSEI already on the table then the call is dropped. This functionality is disabled by default.
Fixed Random TLLI Handling mechanism extends the functionality noted above. A new verification table
has been added to the GbMgr. The table maintains a list of TLLI + NSEI and if an incoming Attach Request
includes a TLLI + NSEI already on the table then the call is dropped. This functionality is disabled by default.
Configuring RTLLI Management
No new commands or keywords have been added to the command line interface (CLI) in support of Fixed
Random TLLI Management. Enabling / disabling this mechanism is integrated into existing CLI.
Random TLLI Management. Enabling / disabling this mechanism is integrated into existing CLI.
For information about the commands, parameters and parameter values, please check your Command Line
Interface Reference manual for each of the commands listed below.
Interface Reference manual for each of the commands listed below.
The following configurations should be performed during system boot up. It is not advisable to
enable/disable this TLLI management functionality during runtime.
enable/disable this TLLI management functionality during runtime.
Important
Verifying Both the RTLLI and the NSEI
To enable the SGSN to handle Attach Requests with the same fixed RTLLI by verifying both the RTLLI and
the NSEI, use the following configuration:
the NSEI, use the following configuration:
config
sgsn-global
gmm-message attach-with-tlli-in-use discard-message only-on-same-nsei
Release Change Reference, StarOS Release 19
390
SGSN Changes in Release 19
RTLLI Management for 2G M2M Devices