The LSUv3 is a high performance multiprocessor system based on the Compact
PCI (cPCI) bus. It uses a pool of Intel (single/multi core) processor cards (PPU Controllers and
Slave Processing Units) to provide the needed processing power. SCC (Serial Communication Controller) cards provide specialised processing
for TDM channels. E1/T1 PCM Line cards, and STM-1/OC-3 ATM, STM-1 SDM (channelised) and
Ethernet interface cards provide connectivity. Commercial cPCI cards can be added for special applications.
Hardware Architecture
The Line Server Unit V.3 (LSUv3) is a high performance multiprocessor
system based on the Compact PCI (cPCI) bus.
The system functions are split among some specialised control units:
the MPU (Main Processing Unit)
a set (1-4) of PPUs (Protocol Processing Unit)
The MPU manages the graphical console, the shared mass storage, the
removable devices and the network interface to the corporate LAN.
The PPUs run the various protocol module that require accurate control
of the processing power and the real time behaviour of the processor.
CPU cards with the highest reliability and performance are selected
from market to meet PRISMA's critical demands forall the other cards has been designed specifically
by our hardware development team with this application in mind.
The excellent system performances are obtained using the last generation
of semiconductor components, and the great reliability and flexibility
of QNX 6 (Neutrino) operating system. Additional commercially available
cPCI cards can optionally be added to the system for special test requirements.
The system is totally scalable in terms of load and interface
cards.
Software Architecture
The LSUv3 keeps the successful modular software architecture of its
precursors (LSU/LSU+), based on the client/server model. This concept
applies both to its internal and external interfaces.
The LSUv3 basically handles the hardware interfaces and the lower layer
of communication protocols, and it allows other client applications, optionally
running on external hosts, to operate at the upper level through a set
of primitives.
Communication between LSUv3 and its clients is based on TCP/IP. Each
LSUv3 software package that manages a specific function (e.g. Configuration
services, Logging services, LAPD services, SS7 services, etc.) provides
a service access point that corresponds to a daemon process that is listening
to a predefined TCP port number.
On the other hand, LSUv3 internal IPC is based on the high performance
message passing mechanism of QNX.
Client applications can run within the LSUv3 environment or on other
hosts and use a local or remote user interface.
This architecture supports concurrent operation of multiple protocol
stacks (e.g. LAPD, SS7, Gb …), and it allows multiple clients to share
the system, of course excluding the layer-1 resources. A key feature of
every LSUv3 protocol implementation is the maximum conformance to the
relevant specifications (ITU, GSM, 3GPP etc.) at upper and lower access
points of the protocol stack.
This also means that the primitives exchanged with the application typically
correspond to what is specified in the related recommendations. Moreover
a set of O&M primitives allows the configuration of the stack and the
layer management functions.
The system startup includes only activation of layer-1 drivers and daemons;
all other protocol modules are activated on demand by the client application.
The interface between LSUv3 software packages and the external world
is fully public. So, on the client side, we can provide the proper solution
or just support the customer that decides to develop autonomously what
is needed, sometimes integrating an already existing proprietary tool.
