Aricent GSN-Lite is a compact, high-performance GPRS
support node (GSN) that can be deployed as SGSN or GGSN or both. In
addition, GSN-Lite can be deployed as a 3G GGSN in 3G networks, thereby
saving extra investments on GGSN during network upgrades.
GSN-Lite is a standardized solution that allows service
providers to offer high-speed Internet services to GPRS subscribers. As a
software solution that can run on any Linux-based PC, Aricent’s GSN-lite is
a cost-effective, highly scalable solution. GSN-Lite is suitable for all
GPRS operators and MVNEs who need to offer high-speed wireless data services
at competitive prices.
GSN-Lite can be deployed quickly and easily, and
without unduly increasing operator capital expenditures. In addition, GSN-Lite’s
maintenance costs are so low that use of this node does not increase
operational expenditures. GSN-Lite is ideal for a variety of deployment
scenarios, including:
- MVNEs launching special data applications. MVNE
connects to the MNO SGSN in the core. The GGSN could be Aricent GSN-Lite
and the MVNE owns the application and charging platforms
- OEMs providing equipment to service providers that
offer data services in rural areas
- Operators in developing markets that require
entry-level GPRS solutions
- Remote islands, villages, and remote areas like
oil exploration fields
- Portable networks
- University campuses
- Emergency disaster recovery sites for restoring
communication services quickly and cost-effectively
- Rural operators who need to upgrade to the GPRS
air-interface in order to maintain roaming agreements with regional or
national carriers
- In maritime communications systems, to enable
connectivity for passengers and crew on cruise ships/ferries
The majority of Aricent’s products are delivered with
tailored combinations of our Lifecycle Services, including Global Innovation
and Design, Product Development, Testing and Certification, Network
Engineering, Maintenance and Support, and Business Operations and Systems
Integration. Aricent’s engineers and consultants have successfully completed
thousands of services engagements globally using flexible delivery models
ranging from on-site to off-shore. Aricent’s services offer deep
communications domain expertise, cost and time efficiencies, quick ramp up
and contemporary commercial engagement models including end-to-end
commitments.
GSN Lite's all-IP architecture in the core network
enables service providers to substantially reduce capital expenditures by
using commercially-available routers and network elements. Service providers
can further reduce their operating expenditures by leveraging the decreasing
cost of IP backhaul. As a software solution, Aricent GSN-Lite interfaces
with legacy solutions, especially with radio networks using Frame
Relay/E1/T1 interfaces and with other network elements, such as HLR and
MSC/VLR, using MTP2/E1/T1.
Aricent's GSN-Lite is a GPRS Support Node that combines
the functionality of a Serving GPRS Support Node (SGSN) as well as a Gateway
GPRS Support Node (GGSN) in the same physical node. It is deployable in GPRS
or EDGE networks to perform the functionality of either SGSN or GGSN on
different physical nodes.
The following figure depicts the deployment of GSN-Lite
in GPRS/EDGE architecture:
GSN-Lite offers valuable features that add flexibility
and performance in the following deployment scenarios:
When deployed as an SGSN, GSN-Lite handles inbound and
outbound packet data traffic that is addressed to/from mobile stations of
users in a geographical area. In addition, it also handles interactions with
the GSM circuit-switched and short messaging infrastructures. As an SGSN,
Aricent's GSN-Lite provides the following functionalities:
- Mobility Management – SGSN supports all mobility
management functions including Attach, Detach, Inter, and Intra SGSN
Routing Area Update (RAU) and Paging.
- SGSN supports HLR addressing, based on an E.214
Mobile Global Title, derived by the SGSN from the IMSI for inter-PLMN
signaling (or on the SPC if intra-PLMN Signaling).
- Session Management – SGSN provides session
management functions, including establishment of Packet Data Protocol
(PDP) contexts, for routing purposes, with the GGSN used by the GPRS
subscriber.
- At PDP context activation, the SGSN negotiates
the Quality of Service (QoS) with the Mobile Station (MS) when the
QoS level requested by the MS cannot be supported. The QoS is
re-negotiated when the QoS, negotiated by the mobile from the
previous SGSN cannot be supported at inter-SGSN RAU.
- The SGSN supports reliability classes 2, 3, 4,
and 5, and accepts all delay classes. However, there is no special
processing done by the SGSN in terms of enforcing relative
importance or absolute time values.
- The SGSN supports the Admission Control
function at each PDP context activation request. The Admission
Control function results either in negotiation of the QoS with the
mobile or in rejection of the PDP Context Activation request. A
request is rejected when the number of simultaneously attached or
activated subscribers increases beyond a specified value.
- The SGSN supports Service Precedence classes
by discarding packets based on the Precedence Class negotiated by
MSs.
- As a part of session management, the SGSN
assists in mean and peak throughputs and policing. While it ensures
that the mean and peak throughputs given to an MS never exceed the
negotiated value, there is no guarantee that the mean or peak
throughput rates can be achieved or sustained for any period.
- SMS – The SGSN supports mobile-originated and
mobile-terminated short messaging through GPRS radio channels.
- Charging Functions – The SGSN supports Call Detail
Record (CDR) generation. M-CDRs, S-CDRs, SMS-MO-CDRs, and SMS-MT-CDRs
generated by the SGSN are sent to the Charging Gateway over the Ga
interface using the GTP protocol.
- Authentication and Identity Check – The SGSN
supports mobile authentication and identity check procedures during
'Attach' and inter-SGSN routing area updates.
- Security – The SGSN supports encrypted
communication to and from mobiles using GEA1 and GEA2 ciphering
algorithms. The GSN-Lite software includes implementation of GEA1 and
GEA2 ciphering algorithms.
- Compression – The SGSN supports TCP header
compression using Van Jacobson and V.42bis data compression techniques
to conserve radio bandwidth while sending data to and from a mobile
station.
- Routing – The SGSN routes the packets received
from a mobile to an appropriate GGSN, based on the APN requested by the
mobile. The SGSN supports interrogation of the DNS to translate the APN
into the IP address of the GGSN.
As a GGSN, Aricent’s GSN-Lite provides the following
functionalities:
- Subscriber Session/Data Management – The GGSN
assigns an IP address to a mobile station. The GGSN supports PDP context
activation for PDP type IPv4.
- The GGSN supports dynamic IP addressing for
subscribers, enabling the operator to use and reuse IP addresses
from a pool of IP addresses allocated to the PLMN/Network by using
local pools configured at the GGSN. Alternatively, the GGSN may use
DHCP for IP address allocation from a configured DHCP server on a
per-APN basis.
- The GGSN supports static IP address allocation
so that subscribers are always provided the same IP address defined
at the time of subscription in the HLR. Otherwise, the RADIUS
protocol could be configured to allocate the same IP address to a
specific subscriber.
- A maximum of five PDP contexts are supported
for one MS. There is one distinct IP address per PDP context.
Negotiated QoS classes for the PDP contexts of an MS can be
different.
- Charging Function – The charging function in the
GGSN sends G-CDRs to the Charging Gateway. G-CDRs output from the GGSN
are ASN.1/BER encoded. In case of a CGF/link failure, the CDRs are
buffered in non-volatile memory (hard-disk) and are transferred to the
CGF on CGF/link recovery.
- Routing – The GGSN routes the packets received
from the SGSN to a default gateway, statically configured at the GGSN,
and routes the packets received from an external PDN for a mobile to an
appropriate SGSN serving the mobiles.
- RADIUS Accounting – GSN-Lite, when used as a GGSN,
can be configured to send accounting information to RADIUS servers
configured according to APN configuration rules. This facilitates the
user to configure the network for applying accounting principles using
the RADIUS mechanism.
As a combined entity, GSN-Lite supports the
functionality of an SGSN and a GGSN as detailed earlier. The combined GSN
can support Inter-SGSN procedures while acting as a GGSN in the Public Land
Mobile Network (PLMN) in which it is deployed. It will continue to act as a
GGSN for the subscribers who have roamed in another PLMN. In addition, GSN-Lite
can be configured to notify occurrence of any significant event or alarm to
configured e-mail addresses, simplifying remote system monitoring.
GSN-Lite supports the following optional procedures as
per the specifications:
- Anonymous PDP context activation/deactivation
procedures.
- Network-Requested PDP Context activation
procedure. This is provided by the support of an optional Gc interface
at the GGSN.
- Combined GPRS/GSM procedures for circuit switched
services. This is provided by using the Base Station Subsystem
Application Part + (BSSAP+) at the optional Gs interface at the SGSN.
For deployment in GPRS networks, GSN-Lite is compliant
to ETSI specifications and ready for deployment in GPRS networks.
For deployment in EDGE networks, GSN-Lite supports a
phased introduction to EDGE. GSN-Lite can be deployed in EDGE networks
'as-is' and can evolve cost effectively to align with the services provided
by network operators. GSN-Lite uses GPRS-compliant Gb interface and Session
Management procedures to inter-work with EDGE-based BSCs and EDGE capable
mobile stations. GSN-Lite provides support for QoS parameters corresponding
to reliability, mean throughput, precedence, delay, and peak throughput as
defined in ETSI specifications. It does not differentiate between different
types of traffic classes (conversational, streaming, interactive, or
background) as introduced in ETSI specifications released for EDGE
compliance and maps them to QoS classes in GPRS when deployed in EDGE
networks. Support for new QoS classes shall be available in future GSN-Lite
releases as per Aricent' road map. For road map details, please contact
Aricent at info@Aricent.com.
End-to-End QoS negotiation and resource reservation is
required during session set-up in the IM Subsystem network for the services
that need QoS better than the best effort service. The Go Interface is
required between GSN-Lite (GGSN) and the Policy-Decision Function (PDF) to
allow Service-Based Local Policy (SBLP) information from the PDF to the
GGSN. GSN-Lite (GGSN) requires the following functional elements and
interfaces to support end-to-end QoS and service-based local policies:
- The Go interface between the GGSN and the PDF use
the Common Open Policy Service (COPS) protocol for QoS signaling.
- The Policy Enforcement Point (PEP) communicates
with the Policy Decision Function (PDF) regarding the Service-Based
Local Policy (SBLP).
- The IP BS Manager manages external bearer services
in the GGSN
Support for IMS services will be available in future
GSN-Lite releases per Aricent's road map. For road map details, please
contact Aricent at info@aricent.com.
GSN-Lite can be enhanced for deployment in 3G networks
with the following enhancements:
- Interfaces towards the RNC (Iu-PS) for Radio
Access Network access
- ATM and IP connectivity to RNCs
The road map for deployment of GSN-Lite for UMTS
networks is as per Aricent's roadmap. For road map details, please contact
Aricent at info@aricent.com.
GSN-Lite, as an SGSN, supports interfaces with the
following elements in a GPRS network:
- Base Station Subsystem (Gb) – Supports Network
Services over Frame Relay using the E1 interface. The interface can be
supported as non-channelized using the entire interface of 2Mbps or
channelized into 64 kbps channels. Alternatively, Network Services may
be supported over IP, a non-standard interface
- HLR (Gr), EIR (Gf), SMS-IWMSC (Gd), MSC/VLR (Gs) –
Supports MAP over SS7 using E1 interfaces towards the HLR, the EIR, and
the SMS-IWMSC; and the BSSAP+ over SS7 using E1 interfaces towards the
MSC/VLR. IP connectivity is also supported towards these network nodes
using SIGTRAN instead of the conventional MTP3 in SS7 suite of protocols
- Charging Gateway (Ga) – Supports GTP’ over UDP/IP
to connect with an external Charging Gateway
- Other GSN – (Gn Supports GTP over UDP/IP to
connect with external SGSNs and GGSNs
As a GGSN, GSN-Lite supports interfaces to the
following elements:
- External IP networks (Gi) and other GSN (Gn) –
Supports connectivity to SGSNs and external IP networks using UDP over
IP.
- HLR (Gc) – Supports MAP over SS7 using E1
interfaces towards the HLR. IP connectivity is also supported using
SIGTRAN instead of the conventional MTP3 in SS7 suite of protocols
- Charging Gateway (Ga) – Supports GTP over UDP/IP
to connect with an external Charging Gateway
GSN-Lite supports four E1/T1 interfaces for SS7 or
Frame Relay links using Adax's High Density Channelized 4 port E1/T1 card.
It also supports up to 128 channels of protocol processing. A maximum of 8
MTP-2 links are supported. The rest of the links can be used for Frame
Relay. For IP interfaces, 10/100 Mbps Ethernet cards are used.
The Operation and Maintenance (O&M) functionality for
the GSN supports Configuration Management, Fault Monitoring, Status
Monitoring, and Statistics Collection.
- Configuration Management – includes system
parameter specifications, the addresses of network components, and the
configuration parameters of protocol stacks.
- Fault Monitoring – The principal goal of Fault
Monitoring is to identify the faults that occur in the GSN. In the GSN,
fault monitoring is achieved by generating alarms.
- Status Monitoring – This involves the collection
and analysis of data related to a GSN node. The GSN allows the periodic
collection of statistics and recording thereof in a log file for
analysis.
GSN-Lite provides management capability with an
intuitive and easy-to-learn, GUI-based manager and remote management with an
SNMP agent shown below:
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http://www.aricent.com/en/product/equipment/signaling_wire_pro_stacks/gsn_lite.html
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http://www.aricent.com/en/product/equipment/signaling_wire_pro_stacks/gsn_lite.html
A Simple Network Management Protocol (SNMP) manager,
through an SNMP Agent, can perform all features supported by the local
manger. The SNMP Agent, along with a comprehensive SMI v1-compliant MIB, is
provided with GSN-Lite.
The SNMP Agent has been developed using the Enhanced
Management Agent through the Extensions Sub Agent Development Kit (EMANATE
SADK)). The GSN-Lite agent is based on the Emanate Master Agent/Sub Agent
architecture.
The Master Agent is in charge of authentication,
authorization, access control, and privacy mechanisms. It receives SNMP
requests and processes them by contacting the appropriate sub agent. The Sub
Agent is specific to the application and provides the required
instrumentation for the objects defined in the MIB. The Master Agent is
Multilingual (SNMP v1, v2, and v3) The Sub Agent for the GPRS Support Node
is protocol independent.
The recommended server configuration for installing
GSN-Lite on Linux is as follows:
- 3.6 GHz Dual Xeon processor with 2MB L2 Cache
- 2 GB DRAM, 400 MHz DDR2,
- Ultra320 SCSI - Universal Hot Plug, High speed
SCSI drives 40 GB
- 3 PCI slots and one hot-plug PCIx card slot Eg: HP
ProLiant DL380 Generation 4 server The following additional hardware is
required for the GSN-Lite SS7/FR configuration:
- One Adax HDC PCI card
The software prerequisites for running GSN-Lite (binary
distribution) are:
Enterprise Red Hat Linux 4.0 (Update 3) host-
Enterprise Server (the ES variant) with Development System and Kernel
Headers. (For pricing-related information please refer to
http://www.redhat.com/software/rhel/purchase/).
- Deployed by several OEMs in multiple global GPRS
networks and laboratories
- Field tested and proven for interoperability with
infrastructure equipment and mobiles of leading vendors, including
Samsung, Nokia, Ericsson, Airnet, Interwave, IPAccess, Vanu, and Tecore.
- A highly mature product and is in commercial use
since 2001.
- Offers an ultra low cost of ownership and zero
obsolescence risk because it runs on any personal computer running the
Linux OS
- Incorporates a highly compact architecture that
combines features of both SGSN and GGSN in the same physical node
- Highly scalable from as low as 100 subscribers to
as high as 50,000 subscribers with path for deployment in 3G networks
- Supports flexible deployment configuration of
either all IP interfaces with BSS, HLR, MSC/VLR, SMS-GMSC and other
SGSN/GGSN(s) or Frame Relay/E1/T1 connectivity with BSC or SS7/E1/T1
interface with HLR, MSC/VLR and SMS-GW
- Aricent legendary responsive support during
integration in factory, field deployment, and in operation
- Availability in flexible licensing models for
field deployment
The GSN-Lite offering is a software package built on
the Linux operating system, available in three distinct configurations:
1. The first configuration allows communication with
the BSS, the HLR, the MSC/VLR, the SMS-GMSC, and other SGSN/GGSN(s) over the
IP (IPv4) interface. In this configuration, Frame Relay over E1 and ITU-T
compliant interfaces towards the HLR, the MSC/VLR, and the SMS Gateway are
used.
2. The second configuration allows communication with
the BSS, the HLR, the MSC/VLR, the SMS-GW, and other SGSN/GGSN(s) over the
IP (IPv4) interface. In this configuration, Frame Relay over T1 and hybrid
ANSI/ITU-T interfaces towards the HLR, the MSC/VLR, and the SMS gateway are
used as per the following:
- The HLR interface – MAP services are run as per
the ETSI specification, which uses the services of ITU-T defined TCAP
with 24bit point code.
- The SMS Gateway interface – The SMS module
utilizes ETSI MAP services, which use ITU-T defined TCAP with 24-bit
point code.
- The MSC/VLR Gateway interface – The 2.5G GSN uses
the ETSI BSSAP+ with 24-bit point code support. The HLR, the SMS, and
the BSSAP+ use ANSI SCCP services over SIGTRAN (M3UA/SCTP/IP). This
configuration is targeted at ANSI networks, such as the US. 3. The third
configuration allows communication interface with the BSS to be frame
Relay/E1 and those with the HLR, the MSC/VLR, and the SMS-GW to be
SS7/E1.
The HLR, the SMS, and the MSC/VLR interfaces run over
ITU-T SS7 with 14-bit point code.
3. The third configuration allows communication
interface with the BSS to be Frame Relay/E1 and those with the HLR, the
MSC/VLR, and the SMS-GW to be MTP2/T1 as per the following:
- The HLR interface – MAP services are run as per
the ETSI specification, which uses the services of ITU-T defined TCAP
with 24-bit point code.
- The SMS Gateway interface – The SMS module
utilizes ETSI MAP services, which uses ITU-T defined TCAP with 24-bit
point code
- The MSC/VLR Gateway interface – The 2.5G GSN uses
ETSI BSSAP+ with 24-bit point code support. The HLR, the SMS, and the
BSSAP+ use ANSI SCCP services over ANSI MTP3. The ANSI MTP3 utilizes the
ANSI MTP2/T1 interface of Adax's HDC PCI card.
The software package contains the following
documentation:
- User Manual – Installation instructions, network
management details including configuration, status, statistics, alarms,
troubleshooting procedures and sizing information.
- Release Bulletin – A summary of the product
release, highlighting the features, assumptions, standard compliance,
delivery file details etc. This will contain a summary of the changes
made in each release over the previous commercial release. It will also
detail the enhancements, bug fixes for a patch release.
- MIB and installations instructions for SNMP Agent