Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
Features and Functionality ▀
SGSN Administration Guide, StarOS Release 18 ▄
When there is a CKSN mismatch
There are situation in which P-TMSI will be reallocated unconditionally:
Inter SGSN Attach/RAU
Inter-RAT Attach/RAU in 2G
IMSI Attach
Avoiding PDP Context Deactivations
The SGSN can be configured to avoid increased network traffic resulting from bursts of service
deactivations/activations resulting from erroneous restart counter change values in received messages (Create PDP
Context Response or Update PDP Context Response or Update PDP Context Request). Be default, the SGSN has the
responsibility to verify possible GTP-C path failure by issuing an Echo Request/Echo Response to the GGSN. Path
failure will only be confirmed if the Echo Response contains a new restart counter value. Only after this confirmation of
the path failure does the SGSN begin deactivation of PDP contexts.
deactivations/activations resulting from erroneous restart counter change values in received messages (Create PDP
Context Response or Update PDP Context Response or Update PDP Context Request). Be default, the SGSN has the
responsibility to verify possible GTP-C path failure by issuing an Echo Request/Echo Response to the GGSN. Path
failure will only be confirmed if the Echo Response contains a new restart counter value. Only after this confirmation of
the path failure does the SGSN begin deactivation of PDP contexts.
Backup and Recovery of Key KPI Statistics
This feature allows the backup of a small set of KPI counters for recovery of the counter values after a session manager
crash.
crash.
Using the feature-specific CLI
statistics-backup sgsn backup-interval
command, in the Global
configuration mode, the operator can enable the feature and define the frequency of the backup; range 1-60 minutes.
In support of this functionality, four schemas (gprs-bk, iups-bk, map-bk, sgtp-bk) have been defined with stats, derived
from the SGSN and SGTP schemas, that will be backed up for recovery of their counter values.
from the SGSN and SGTP schemas, that will be backed up for recovery of their counter values.
For more information about the schema, refer to the Statistics and Counters Reference. For more information about this
functionality and configuration for this feature, refer to the Backup and Recovery of Key KPI Statistics feature chapter in
this Guide.
functionality and configuration for this feature, refer to the Backup and Recovery of Key KPI Statistics feature chapter in
this Guide.
Bulk Statistics Support
System support for bulk statistics allows operators to choose which statistics to view and to configure the format in
which the statistics are presented. This simplifies the post-processing of statistical data since it can be formatted to be
parsed by external, back-end processors.
which the statistics are presented. This simplifies the post-processing of statistical data since it can be formatted to be
parsed by external, back-end processors.
When used in conjunction with the Web Element Manager, the data can be parsed, archived, and graphed.
The system can be configured to collect bulk statistics (performance data) and send them to a collection server (called a
receiver). Bulk statistics are statistics that are collected in a group. The individual statistics are grouped by schema. The
following is the list of schemas supported for use by the SGSN:
receiver). Bulk statistics are statistics that are collected in a group. The individual statistics are grouped by schema. The
following is the list of schemas supported for use by the SGSN:
System: Provides system-level statistics
Card: Provides card-level statistics
Port: Provides port-level statistics
DLCI-Util: Provides statistics specific to DLCIs utilization for CLC-type line cards
EGTPC: Provides statistics specific to the configured ETPC service on the S4-SGSN