Ericsson BSC is build up with AXE 810 architecture. It is more powerful, less space and power dissipating. The hardware components are:
1. GEM (Generic Ericsson Magazine)
2. Group Switch GS 890 (distributed, non-blocking) 3. CL 890 (new clock modules)
4. On board RP (RPI)
5. ET 155-1 (one board ET 155) 6. APG – 40
An important factor behind the AXE flexibility is the APZ Control System Architecture, which is a two-level architecture including both central and distributed control. It is an approach that ensures high reliability and efficient call handling.
APG Adjunct Processor Group
CP Central
48 CP & RP
The Central Processor, CP is duplicated, offering high hardware fault tolerance. In the event of a fault, the control may be swapped to the other side with a minimum or no impact on the traffic handling capability.
The Regional Processors, RPs, are used for routine repetitive processing and for processing intensive tasks such as the termination of the lower protocol layers. The most recent regional processors are open processing platforms, on which it is possible to run application software using industry-standard programming languages such as C or C++. The use of high-level languages also presents other opportunities such as substantial Time to Market gains through the incorporation of off-the-shelf standard software modules.
RPP is targeted to support data communication related telecommunication applications.
RPP offers a range of open hardware interfaces, a range of software applications plus a complete development environment. It work as a PCU (Packet Control Unit)
The PCU is a node in the GSM network. It is designed to provide an interface between the circuit-switched GSM network and the packet-switched GSN nodes. These GSN nodes in turn provide an interface to public packet-switched networks.
The hardware consists of 1-7 RPPs and 2 no of EPSs which can be connected together using Ethernet i.e. IP. Each RPP can connect to the SGSN (via the Group Switch when FR is used).
For GB over IP EPS card connects SGSN directly through the BSC internal IP Gateways . Each RPP card provides 64 circuits of 64kbps per circuit. If GB over Frame Relay is used 31circuits will be utilized for 2MB connectivity with SGSN and rest 33 circuits will be used for radio access. All the 64 circuits can also be used for radio access if GB over IP is used. In GB over IP configuration the EPS card provide up to 100 mbps bandwidth with SGSN through IP gateway and work in redundancy mode. In this case all the RPP resource will be utilized for radio access.
Inter Platform Network
An Ethernet based, 100 Mbps or 1 Gbps, Inter Platform Network, IPN, is ringing in an industry standard, high capacity interface into AXE.
Other Systems,
AP AP e.g. TSP, AXD 301
CP IPN
49 Generic Ericsson Magazine
Another far-reaching improvement is the GEM, a high-capacity, flexible, and scalable magazine (sub-rack) that anticipates future developments. GEM-based nodes will be smaller, dissipate less power, and have greater maximum capacity. Their implementation will dramatically improve the cost of ownership and cut time-to-customer for AXE.
A GEM can house
• two SCB-RPs, providing an Ethernet switch, control function, maintenance support, and power distribution;
• two switch boards (XDB), providing a 16 K plane duplicated group switch;
• up to 22 device boards with 15 mm spacing, such as ET155, ECP, or TRA;
• pairs of DLEBs, providing multiplexing functionality for DL3 cable interfaces, placed in device slots; and
• CL890 clock modules placed in device slots.
Transcoder
The Transcoder/Rate Adaptation (TRA) function in BSC/TRC performs transcoding of speech information and rate adaptation of data information. It also contains functions for Discontinuous Transmission (DTX). The capacity in number of channels per board for the different versions of TRA hardware is given below.
TRA HW
TFO 24 per device group of any speech codec (n=1..8), 192 in total R6B 24 per device group of any speech codec (n=1..8), 192 in total R6 with TFO
For R5 different codec cannot be mixed on the same board. Each TRA R6/R6B board consists of 8 device groups and each device group can be configured for any of the supported codec.
The capacity for TRA R6 differs depending on if the device group is configured to support TFO, in that case a device group can handle 16 channels. Else and for TRA R6B the capacity is 24 channels per device group.
One TRA EM consists of one TRA board. The TRA R5 magazine includes (up to) 16 TRABs. TRA R6/R6B is housed in a GEM magazine where it can be mixed with other boards depending on the configuration. All TRA hardware versions can be mixed in the same speech codec pool. Presently we are using CSPB R2 board which work on R6B application.
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Note that, when there are several pools, it is normally the case that AMR, EFR or HR capable mobiles also support FR. In this case the traffic can be shared between the pools and thus not all of them need to be dimensioned for the same grade of service. This means that congestion in one pool, for example, the EFR pool, does not necessary imply congestion for a call, as another pool, e.g. the FR pool, can be used instead.
ET-155
The ET155-1 OC-3 is a single board 155 Mb/s, OC-3, Exchange Terminal supporting ANSI standards for SONET. The ET155-1 OC-3 together with the GEM concept of AXE offers very compact and scalable node solutions for cost efficient connections to the transport network. For the purposes of equipment and network protection, Automatic Protection Switching, APS 1+1, can be provided as an option. For Abis link E1 is required which can be extracted by connecting 2Mb MUX (OMS) with ET155-1.
OMS
OMS is a MUX which convert one TM to 63 E1. It is a separate equipment and not under AXE environment. For the maintenance of OMS its O&M software to be loaded in Laptop and by connecting the Laptop to OMS’s console the Card configuration and E1 configuration can be done. Sometimes, on power recycle, the E1 configuration of OMS gets corrupted. To rectify this we have to logging into OMS through console and through O&M command reconfiguration can be done.
APG 40
The APG40 is a platform for the AXE central processor IO functions (APIO) that were inherited from the IOGs. It is also a platform for billing (for example, FOS) and statistic data collecting (for instance, STS), storage, processing and output from the AXE switch. For example, the APG40 can be a platform for collecting data related to in-service performance from the central processor. It can also format that data for distribution to an operations management.