GPRS Gb Interface Stack

The use of GPRS technology facilitates the provision of packet mode data services to GSM networks and speeds up data transfer rates upto 115 kbps. It provides new and superior applications for mobile users, by supporting different packet data protocols (IP, X.25) and offering select services to users through different Quality of Service. OEMs benefit through GPRS, as it enables shared use of radio resources, data volume dependent charging and offers higher efficiency of radio resources.
http://www.hssworld.com/mobile/stacks/GB_INTERFACE/overview.htm

The GPRS Gb Interface Stack from Aricent has been developed for both the SGSN (Serving GPRS Support Node) and BSS/PCU (Packet Control Unit) nodes. The BSS -Gb product can be used to upgrade an existing GSM BSS equipment and provide GPRS based packet data services. On the other hand, SGSN vendors can use the SGSN-Gb product to build their equipment. This support will help GSM networks provide packet-data based services and applications like mobile Internet, mobile e-mail access and wireless VPNs. Both the stack products are equally attractive for use by Test & Measurement tool vendors.

Aricent’ GPRS Gb Stack consists of the following layers:

* SNDCP
* LLC
* BSSGP (both BSS and SGSN sides)
* NS (both BSS and SGSN sides)



Aricent’ GPRS Gb Stack: Architecture
The Gb stack has the following architecture on the SGSN side:


Aricent’ GPRS Gb Stack: Subsystems

SNDCP

* Transmission and reception of N-PDUs in Acknowledged and Unacknowledged LLC mode
* Multiplex several packet data protocol packets for same MS
* Multiplex several instances of a packet data protocol for same MS
* Segmentation and Re-assembly of network packets to/from LLC frames
* Header Compression(RFC1144 and RFC 2057)
* Data Compression(V.42bis)
* Transmission and reception of variable length N-PDUs
* Parameter Negotiation
* Buffers N-PDUs for acknowledged mode services

LLC

* Provides reliable logical MS-SGSN link
* Variable length frames
* Acknowledged and Un-acknowledged transfer
* Protected and Unprotected payloads
* Permits communication between one SGSN and multiple MS over same medium
* Parameter Negotiation
* User Data Confidentiality using Ciphering
* Supports Multiple LLEs per TLLI
* Provides flow control in the Asynchronous Balanced Mode (ABM)
* Error Detection, Recovery and Notification
* Provide Sequence Control to maintain the sequential order of frames across a logical link connection

BSSGP

* Separate BSSGP-SGSN and BSSGP-BSS software modules
* Efficient implementation of flow control algorithm provides support for features like:
o Delay class
o QoS
o Priority and frame lifetime
o Dynamic BVCI learning
o Plugable customized flow control algorithms
* Transfer of LLC Frames between BSS and SGSN
* Transfers GPRS Mobility Management (GMM) Protocol Data Units (PDUs) between BSS and SGSN
* Transfers Network Management (NM) PDUs between BSS and SGSN
* Flow Control on the down-link
* LL-FLUSH procedures
* Auto Flush

NS

* Designed to accommodate a wide variety of boards/hardware configurations
* Provides support for:
o Hash based load sharing
o Identifying a frame relay link as foreign or local. This helps in avoiding traffic on the back plane bus in case the hardware design involves NS-VCs belonging to one NSEI spanning multiple Gb boards
o FR or IP based sub network services (SNS) layer
* Transmission of NS SDU
* Encapsulation of NS SDU
* Load Sharing across NSVC
* Congestion Detection and Reporting
* Block/Unblock procedures for NSVC
* Reset and Test procedures for NSVC
* Status Indication



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Operation and Management Support

GPRS Gb Product provides extensive operation and management support as well as debugging assistance via:

* Run-time control of capacity and configuration parameters
* Extensive statistics collection (API protocol, internal events and error statistics)
* Error/alarm reporting
* Multi-level tracing supports (detailed and brief traces)

Conformance to Standards

* SNDCP for SGSN (Gb interface)
o 3GPP TS 44.065 V 5.0.0 June 2002 Release 5
o 3GPP TS 44.065 V 4.2.0 June 2002 Release 4
o 3GPP TS 44.065 V 8.1.0 Sept 2000 Release 99

* LLC for SGSN (Gb interface)
o 3GPP TS 44.064 V 5.1.0 March 2002 Release 5
o 3GPP TS 44.064 V 4.3.0 March 2002 Release 4
o 3GPP TS 44.064 V 8.6.0 December 2000 Release 99

* BSSGP for SGSN (Gb interface)
o 3GPP TS 48.018 V 5.5.0 September 2002 Release 5
o 3GPP TS 48.018 V 4.5.0 June 2002 Release 4

3GPP TS 48.018 V 8.a.0 June 2002 Release 99

* NS for SGSN (Gb interface)
o 3GPP TS 48.016 V 5.1.0 December 2001 Release 5
o 3GPP TS 48.016 V 4.2.0 December 2001 Release 4
o 3GPP TS 48.016 V 8.0.1 June 2002 Release 99

* BSS GPRS Protocol (BSSGP) for BSC
o 3GPP TS 48.018 V5.10.0 May 2004 Release 5
o 3GPP TS 48.018 V4.7.0 May 2004 Release 4
o 3GPP TS 48.018 V8.c.0 May 2004 Release 99

* Network Service (NS) for BSC
o 3GPP TS 48.016 V5.3.0 July 2004 Release 5
o 3GPP TS 48.016 V4.4.0 July 2004 Release 4
o 3GPP TS 48.016 V 8.0.1 June 2002 Release 99


Support extended to Release 5 for all these stacks.



Aricent first to announce solutions that accelerate the move from GPRS to All IP wireless networks. Read the press release.