Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
▀ Features and Functionality
▄ SGSN Administration Guide, StarOS Release 18
inter-SGSN RAU. This feature is configured through the Call-Control Profile Configuration Mode which is part of the
feature set.
feature set.
Lawful Intercept
The Cisco Lawful Intercept feature is supported on the SGSN. Lawful Intercept is a license-enabled, standards-based
feature that provides telecommunications service providers with a mechanism to assist law enforcement agencies in
monitoring suspicious individuals for potential illegal activity. SGSN supports use of IP Security (a separate license-
enabled, standards-based feature) for the LI interface; for additional information on IPSec, refer to the Cisco StarOS IP
Security (IPSec) Reference. For additional information and documentation on the Lawful Intercept feature, contact your
Cisco account representative.
feature that provides telecommunications service providers with a mechanism to assist law enforcement agencies in
monitoring suspicious individuals for potential illegal activity. SGSN supports use of IP Security (a separate license-
enabled, standards-based feature) for the LI interface; for additional information on IPSec, refer to the Cisco StarOS IP
Security (IPSec) Reference. For additional information and documentation on the Lawful Intercept feature, contact your
Cisco account representative.
Lawful Interception Capacity Enhanced
In a full ASR5K chassis with PSC2 cards the maximum number of attached users is about “4” million. In previous
releases, it was possible to configure and intercept 20000 camp-on users on the chassis. With this feature enhancement
the lawful interception capacity of has been increased to 4% of the maximum number of attached users, that is 160,000
camp-on users (4% of 4 million subscribers). It is now possible to configure and intercept 160000 camp-on users on the
chassis.
releases, it was possible to configure and intercept 20000 camp-on users on the chassis. With this feature enhancement
the lawful interception capacity of has been increased to 4% of the maximum number of attached users, that is 160,000
camp-on users (4% of 4 million subscribers). It is now possible to configure and intercept 160000 camp-on users on the
chassis.
Link Aggregation - Horizontal
The SGSN supports enhanced link aggregation (LAG) within ports on different XGLCs. Ports can be from multiple
XGLCs. LAG works by exchanging control packets (Link Aggregation Control Marker Protocol) over configured
physical ports with peers to reach agreement on an aggregation of links. LAG sends and receives the control packets
directly on physical ports attached to different XGLCs. The link aggregation feature provides higher aggregated
bandwidth, auto-negotiation, and recovery when a member port link goes down.
XGLCs. LAG works by exchanging control packets (Link Aggregation Control Marker Protocol) over configured
physical ports with peers to reach agreement on an aggregation of links. LAG sends and receives the control packets
directly on physical ports attached to different XGLCs. The link aggregation feature provides higher aggregated
bandwidth, auto-negotiation, and recovery when a member port link goes down.
Local DNS
Previously, the SGSN supported GGSN selection for an APN only through operator policy, and supported a single pool
of up to 16 GGSN addresses which were selected in round robin fashion.
of up to 16 GGSN addresses which were selected in round robin fashion.
The SGSN now supports configuration of multiple pools of GGSNs; a primary pool and a secondary. As part of DNS
resolution, the operator can use operator policies to prioritize local GGSNs versus remote ones. This function is built
upon existing load balancing algorithms in which weight and priority are configured per GGSN, with the primary
GGSN pool used first and the secondary used if no primary GGSNs are available.
resolution, the operator can use operator policies to prioritize local GGSNs versus remote ones. This function is built
upon existing load balancing algorithms in which weight and priority are configured per GGSN, with the primary
GGSN pool used first and the secondary used if no primary GGSNs are available.
The SGSN first selects a primary pool and then GGSNs within that primary pool; employing a round robin mechanism
for selection. If none of the GGSNs in a pool are available for activation, then the SGSN proceeds with activation
selecting a GGSN from a secondary pool on the basis of assigned weight. A GGSN is considered unavailable when it
does not respond to GTP Requests after a configurable number of retries over a configurable time period. Path failure is
detected via GTP-echo.
for selection. If none of the GGSNs in a pool are available for activation, then the SGSN proceeds with activation
selecting a GGSN from a secondary pool on the basis of assigned weight. A GGSN is considered unavailable when it
does not respond to GTP Requests after a configurable number of retries over a configurable time period. Path failure is
detected via GTP-echo.