для Cisco Cisco ASR 5500
Serving GPRS Support Node (SGSN) Overview
▀ SGSN Core Functionality
▄ SGSN Administration Guide, StarOS Release 17
38
Both dynamic and static addresses for the PDP contexts are supported.
The SGSN provides configuration to control the duration of active and inactive PDP contexts.
When activating a PDP context the SGSN can establish the GTP-U data plane from the RNC through the SGSN to the
GGSN or directly between the RNC and the GGSN (one tunnel).
GGSN or directly between the RNC and the GGSN (one tunnel).
The SGSN is capable of interrogating the DNS infrastructure to resolve the specified APN to the appropriate GGSN.
The SGSN also provides default and override configuration of QoS and APN.
The SGSN also provides default and override configuration of QoS and APN.
PDP Context Modification
This procedure is used to update the MN and the GGSN. The SGSN is capable of initiating the context modification or
negotiating a PDP context modification initiated by either the MN or the GGSN.
negotiating a PDP context modification initiated by either the MN or the GGSN.
PDP Context Deactivation
This procedure is used to deactivate PDP contexts. The procedure can be initiated by the MN or the SGSN. The SGSN
provides configurable timers to initiate PDP deactivation of idle contexts as well as active contexts.
provides configurable timers to initiate PDP deactivation of idle contexts as well as active contexts.
PDP Context Preservation
The SGSN provides this functionality to facilitate efficient radio resource utilization. This functionality comes into play
on the following triggers:
on the following triggers:
RAB (Radio Access Bearer) Release Request
This is issued by the RAN to request the release of RABs associated with specific PDP contexts. The SGSN
responds with a RAB assignment request, waits for the RAB assignment response and marks the RAB as
having been released. The retention of the PDP contexts is controlled by configuration at the SGSN. If the PDP
contexts are retained the SGSN is capable of receiving downlink packets on them.
responds with a RAB assignment request, waits for the RAB assignment response and marks the RAB as
having been released. The retention of the PDP contexts is controlled by configuration at the SGSN. If the PDP
contexts are retained the SGSN is capable of receiving downlink packets on them.
Iu Release Request
The RAN issues an Iu release request to release all RABs of an MN and the Iu connection. The retention of the
PDP contexts is controlled by configuration at the SGSN. When PDP contexts are retained the SGSN is
capable of receiving downlink packets on them.
PDP contexts is controlled by configuration at the SGSN. When PDP contexts are retained the SGSN is
capable of receiving downlink packets on them.
When PDP contexts are preserved, the RABs can be restored on a service request from the MN without having
to go through the PDP context establishment process again. The service request is issued by the MN either
when it has some data to send or in response to a paging request, on downlink data, from the SGSN.
to go through the PDP context establishment process again. The service request is issued by the MN either
when it has some data to send or in response to a paging request, on downlink data, from the SGSN.
Charging
Charging functionality for the SGSN varies depending upon the type of network in which it is deployed.
SGSN in GPRS/UMTS Network
The SGSN provides an efficient and accurate billing system for all calls and SMSs passing through the SGSN. The
charging-specific interfaces and 3GPP standards supported by the SGSN deployments are listed below:
charging-specific interfaces and 3GPP standards supported by the SGSN deployments are listed below:
Allows the configuration of multiple CGFs and a single GSS in a single GTPP group along with their relative
priorities.