Cisco Cisco ASR 5000
Page Throttling
▀ How it Works
▄ SGSN Administration Guide, StarOS Release 18
The following modules inter-work with each other to achieve page throttling in a GPRS scenario:
1. The Session Manager
2. The GPRS Application
3. The GMM Layer
4. The GPRS Stack
5. RLF Module
Consider the following GPRS scenario, where the SGSN wants to send downlink data or signalling messages to a
subscriber and the subscriber is in a STAND-BY state:
subscriber and the subscriber is in a STAND-BY state:
1. The SGSN initiates a paging message to identify the subscriber's current location.
2. The GPRS application sends an indication to the GMM layer whenever it wants to page the MS either for
signalling or data packets. Throttling of paging messages for GPRS is performed at the GMM layer in the
Session Manager (SESSMGR). Throttling can be performed either at the Global or NSE level.
Session Manager (SESSMGR). Throttling can be performed either at the Global or NSE level.
3. For throttling at the global level, the RLF context is created at the Session Manager level and is maintained in the
GMM Control block in the GMM layer.
4. For throttling at the NSE level, the RLF context is created at the Session Manger level for each NSE and is
maintained in the NSE control block in the GMM layer.
5. The GMM layer collects the information about the subscriber to be paged and sends it to the RLF module for
throttling. The RLF template is configurable, and the RLF module performs the throttling function based on the
thresholds configured in the template.
thresholds configured in the template.
6. The RLF module applies the rate limiting algorithm based on the configured limits. It sends or queues paging
message based on the configured limits, once the maximum rate or the configured threshold is reached the
paging messages are dropped by the RLF module.
paging messages are dropped by the RLF module.
7. The GMM layer registers the call-back functions which are used by RLF module to send the paging messages
out of SGSN.
Page Throttling in an UMTS Scenario
The diagram below represents the design of the Page Throttling feature in a 3G scenario: