Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
▀ Network Deployments and Interfaces
▄ SGSN Administration Guide, StarOS Release 18
Ga: The SGSN uses the Ga interface with GPRS Transport Protocol Prime (GTPP) to communicate with the
charging gateway (CG, also known as CGF) and/or the GTPP storage server (GSS). The interface transport
layer is typically UDP over IP but can be configured as TCP over IP for:
layer is typically UDP over IP but can be configured as TCP over IP for:
One or more Ga interfaces per system context, and
An interface over Ethernet 10/100 or Ethernet 1000 interfaces
The charging gateway handles buffering and pre-processing of billing records and the GSS provides storage for
Charging Data Records (CDRs). For additional information regarding SGSN charging, refer to the Charging
section.
Charging Data Records (CDRs). For additional information regarding SGSN charging, refer to the Charging
section.
IuPS: The SGSN provides an IP over ATM (IP over AAL5 over ATM) interface between the SGSN and the
RNCs in the 3G UMTS radio access network (UTRAN). RANAP is the control protocol that sets up the data
plane (GTP-U) between these nodes. SIGTRAN (M3UA/SCTP) or QSAAL (MTP3B/QSAAL) handle IuPS-C
(control) for the RNCs.
plane (GTP-U) between these nodes. SIGTRAN (M3UA/SCTP) or QSAAL (MTP3B/QSAAL) handle IuPS-C
(control) for the RNCs.
Some of the procedures supported across this interface are:
Control plane based on M3UA/SCTP
Up to 128 Peer RNCs per virtual SGSN. Up to 256 peers per physical chassis
SCTP Multi-Homing supported to facilitate network resiliency
M3UA operates in and IPSP client/server and single/double-ended modes
Multiple load shared M3UA instances for high-performance and redundancy
Works over Ethernet and ATM (IPoA) interfaces
Facilitates SGSN Pooling
RAB (Radio Access Bearer) Assignment Request
RAB Release Request
Iu Release Procedure
SGSN-initiated Paging
Common ID
Security Mode Procedures
Initial MN Message
Direct Transfer
Reset Procedure
Error Indication
SRNS relocation
Gb: This is the SGSN’s interface to the base station system (BSS) in a 2G radio access network (RAN). It
connects the SGSN via UDP/IP via an Ethernet interface or Frame Relay via a Channelized SDH or SONET
interface (only available on an ASR 5000 chassis). Gb-IP is the preferred interface as it improves control plane
scaling as well as facilitates the deployment of SGSN Pools.
interface (only available on an ASR 5000 chassis). Gb-IP is the preferred interface as it improves control plane
scaling as well as facilitates the deployment of SGSN Pools.
Some of the procedures supported across this interface are:
BSS GSM at 900/1800/1900 MHz
BSS Edge