mcBSC and mcTC architecture
The major architectural change with the mcBSCand the mcTC is the move from multi-subrack blade system to a few rack
mount modules. Depending on the capacity needs, one mcBSC can consist of two up to several modules. A
multicontroller module is tightly integrated and has only a few field-replaceable parts.
The new Multicontroller HW platform allows new, optimized placement of the BSC and transcoder functionalities in the
system.
Functional architecture of the mcBSC
Figure 7 shows the general functional architecture of the mcBSC. The functions are distributed in entities of hardware and
software. The 1G and 10G interfaces are available for external connections towards site routers. The main functional units
of the mcBSC are:
BSC signaling unit (BCSU)
Marker and cellular management unit (MCMU)
Operation and maintenance unit (OMU)
Packet control unit (PCUM)
Ethernet transmission processing (ETP)
Figure 7:
Functional architecture of the mcBSC
The general ETP functionality contains ETME and ETMA functionalities.
The distributed processing architecture of the mcBSC is implemented by a multiprocessor system, where the data
processing capacity is divided among several processors.
Based on the application needs general purpose processing units can be assigned to different tasks.
Internal communications (internal messaging) between the functional units of the system is based on Ethernet.
The mcBSC functional units are briefly described below:
BSC signaling unit (BCSU)
The BSC signaling unit (BCSU) is a TRX-capacity unit of the mcBSC. It performs those BSC functions that are highly
dependent on the volume of traffic. The BCSU consists of two parts, which correspond to the A over IP (AoIP) and Packet
Abis interfaces.
The AoIP interface part of the BCSU is responsible for the following tasks:
Performing the functions of SIGTRAN based SS7 signaling
Performing all message handling and processing functions of the signaling channels connected to it
The Packet Abis interface part of the BCSU controls the air interface channels associated with transceivers and Abis
signaling channels. The handover and power control algorithms reside in this functional unit.
Packet control unit (PCU)
The PCU unit is an independent processing unit logically connected to the BSCU. The PCU unit performs all the data
processing tasks related to GPRS/EDGE traffic. It implements packet switched traffic oriented Gb and Packet Abis
interfaces in the mcBSC.
The PCU controls GPRS/EDGE radio resources and acts as the key unit in the following procedures:
GPRS/EDGE radio resource allocation and management
GPRS/EDGE radio connection establishment and management
Data transfer
Coding scheme selection
PCU statistics
Ethernet transmission processing (ETP)
In the mcBSC, A and Abis interfaces are connected to an IP network. The ETP functionality terminates all external
management, user and control plane IP traffic, handling the Ethernet transmission processing which is related to AoIP
and Packet Abis interfaces in the mcBSC. The general ETP functionality contains ETME and ETMA functionalities. With
the mcTC implementation, when transcoder is located in the BSS, ETP functionality handles the needed Ethernet
transmission processing related to used Packet Ater interface between the mcBSC and the mcTC.
Marker and cellular management unit (MCMU)
The MCMU has centralized cellular management functions for controlling cells and radio channels for the mcBSC. The
MCMU reserves and keeps track of the radio resources requested by the MSC and the handover procedures of the
mcBSC. The MCMU also manages the configuration of the cellular network.
Operation and maintenance unit (OMU)
The Operation and Maintenance Unit (OMU) is an interface between the mcBSC and a higher-level network management
system and/or the user. The mcBSC can provide full-scale traffic capacity even when O&M interface towards NetAct is
disconnected.
The OMU can also be used for local operations and maintenance. The OMU receives fault indications from the mcBSC. It
can produce local alarm printouts to the user or send the fault indications to NetAct.
In the event of a fault, the OMU automatically activates appropriate recovery and diagnostics procedures within the
mcBSC. Recovery can also be activated by the MCMU if the OMU is lost. The tasks of the OMU can be divided into four
groups:
Traffic control functions
Maintenance functions
System configuration administration functions
System management functions
Functional architecture of the mcTC
The general functional architecture of the mcTC is shown in Figure 8.
Figure 8:
Functional architecture of the mcTC
The functions are distributed in entities of hardware and software. The main functional units of the mcTC are:
ETP, which is responsible for terminating all external management, user and control plane IP traffic.
Transcoding unit (TCU), which implements transcoding and rate adaptation and other media processing
functions for the mcTC.
Management and control unit (MCU), which implements transcoder control, management and centralized
O&M tasks in the mcTC module.
mcBSC and mcTC hardware architecture
The mcBSC and the mcTC are based on the Multicontroller HW platform in which motherboard provides the following
main functions:
Slots for add-in cards
Ethernet switch
AMC expansion slots
Power supply and cooling
Add-in cards provides the processing functionality. The mcBSC and the mcTC products efficiently utilize general purpose
processing units with SW configurable functionality for control, O&M and user plane as well as for Ethernet transmission
processing and transcoding purposes.
External physical interfaces
Network interfaces provide external interfaces and the means to execute physical layer and transport layer functions.
Any interface can be configured to be used as an Abis, A, Gb or Ater interface.
External physical interfaces towards site routers can be either 1G or 10G with relevant SFP modules.
In addition to the network interfaces, local area network (LAN) interfaces as well as debugging and maintenance
interfaces are provided in front of the module.
The controller module front panel is shown in Figure 9.
Figure 9:
Physical interfaces of controller module
Gigabit Ethernet interfaces
IP over Ethernet network interfaces with protection possibility are provided in the front panel of the module. One module
may contain up to 16 pcs of Gigabit Ethernet interfaces and up to 6 pcs of interfaces, that can be used either in 1 Gbps or
10Gbps speed.
All these interfaces use standard SFP and SFP+ (for 10GE) connectors.
Interface Type
Gigabit Ethernet
Standard
IEEE 802.3-2005
Physical layer
1000Base-SX
1000Base-LX
1000Base-T
Connections
SFP/LC
SFP/LC
SFP/RJ-45
Number of interfaces
16 + 2 pcs in the node
Table 1:
Interface specifications for network connections and element management
Interface Type
1 and 10 Gbps Ethernet
Standard
IEEE 802.3-2005
Physical layer
1000Base-SX
1000Base-LX
1000Base-T
Connections
SFP/LC
SFP/LC
SFP/RJ-45
Physical layer
10GBase-SR
10Base-LR
10GDirect Attach
Connections
SFP+/LC
SFP+/LC
SFP+/copper
Number of interfaces
6 pcs in the node
Table 2:
Interface specifications for connections to be used either for module interconnects or network connections
LAN/Ethernet for O&M interfaces
The local area network interface functions at the rate of 10/100/1000 Mbps using an RJ45 connector located in the front
panel.
SW download and SW debugging interfaces
One USB type B interface for debugging and two USB type A interfaces for SW download are provided on the front panel.
Serial Port interface
Standard RS-232 interface with a RJ-45 connector, used for connection to the Local Management Processor.
External Alarm interface
Standard RJ-45 connector, used for collecting external alarm inputs for monitoring purpose.
External Telecom Synchronization interface
Two standard RJ-45 connectors, used for external E1, T1, J1, 2.048 MHz, and 1.544 MHz input and output reference.
mcBSC synchronization connectors are used for maximum two external inputs (multibox or unibox) and remaining
connectors are used for chaining box synchronization.
External HD cross connection
Standard SAS connector, used for cross connecting hard disks between two controller module boxes.
External Packet Synchronization Interfaces
Optional Multicontroller Packet Timing Unit (PTUM) is used for mcBSC packet synchronization. This unit implements
Ethernet Packet synchronization IEEE1588v2 PTP protocol and Synchronous Ethernet (SyncE) for physical layer
synchronization. It can be used in master or slave modes.
Packet Synchronization interfaces are available with BSAC-A AMC card.
Two Standard SFP connectors, used for external 100M/1GE Ethernet providing IEEE 1588 or Synchronous Ethernet
timing.
Two Standard RJ-45 connectors, used for external E1, T1, J1, 2.048 MHz input (and output) reference or GPS input.
Element Management 1GigE Interface
One 1 GigE (1000Base-T) interface for local hardware management and debugging purposes.
Id: 0900d8058080196c
DN0947925
©2011 Nokia Siemens Networks