An Introduction to the Ericsson Transport Network Architecture ...

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86 The control signals, which come from the Vertical Control Board (VCB), are distributed to all SMBs. In addition, HCB collects external alarms, e.g. temperature, fans, etc. The VCB is the core of the control functions in the AXD 4/1. Packet handling and control of the Switch plane are the two main tasks performed by the VCB, which contains the Unit Processor (UP). The packet handling is performed by a Router. The Router continuously looks for a packet to be routed and keeps track of the packet load. The UP handles the control of the entire Switch plane by controlling the Device Processors (DP) located on the respective boards in the Switching Cabinet. The Distribution Matrix Board (DMB) terminates four incoming SNI-4s from Devices, and separates the traffic part of the signal from the control information carried in the internal overhead of the SNI-4. The traffic signals are distributed to all the Switching Matrix Boards (SMB) in the cabinet. The VCB handles the separated control information for routing. One SWC can be equipped with up to sixteen DMBs. The SMB is the heart of the Switch. It contains the Switch for four outgoing SNI-4 signals. In addition, four outputs used for expansion are located at the SMB. These ports are used to interconnect two SWCs when expanding the switch. Each SMB is connected to all DMBs in the cabinet. Up to sixteen SMBs can be accommodated in one SWC. Each board is equipped with a microprocessor for board supervision (DP). Devices TAU 140, Figs. 6 and 7, interfaces 140 Mbit/s plesiochronous line signals according to CCITT G.703. TAU 140 can be set to different modes, which allows for branching at 2, 34, and 140 Mbit/s level and makes switching at these levels possible. TAU 140 contains five different types of ASIC. Together they handle CMI-decoding of 140 Mbit/s line signals, framing and maintenance at the 140,34,8 and 2 Mbit/s levels, buffering and frequency justification between line signals, synchronisation, generation of the synchronous IVC-4 frame and sending of SNI-4 to all three switch planes. TAU 140 has the corresponding functionality in the transmit direction, completed with majority vote for data and clock signals from three switch planes. TAU 140 contains approximately 1.5 Million used gates, processor block with 256 kWord-PROM, 512 kWord-RAM, DC/DC converters and a number of analog high speed blocks. TAU STM-1E interfaces 155 Mbit/s electric line signals belonging to the Synchronous Digital Hierarchy, and performs demap- Fig.6 TAU 140 ERICSSON REVIEW No. 3.1992
87 Fig. 7 TAU 140 functionality FS Frame Synchronisation ping of an STM-1 line signal to VC-12s and maintenance of them, pointer adjustment, buffering, mapping into IVC-4 which is sent to the three planes of the Switching Network. TAU STM-1 E has the corresponding functionality in the transmit direction completed with majority vote. TAU STM- 1E contains six different types of ASIC. TAU 140 and TAU STM-1 E are placed in the same magazine which can be equipped with up to sixteen TAUs, arbitrarily placed and mixed. TAU 34 interfaces 34 Mbit/s plesiochronous line signals. Two different types of ASIC, common to TAU 34 and TAU 140, are used. The signal from TAU 34 in the direction towards the switch is a triplicated SNI-3. I n order to make optimal use of the capacity of the Switching Network, a unit called Terminal Connection Unit (TCU) and located between TAU 34 and the switch has been designed, Fig 4. This unit multiplexes four SNI-3s to one SNI-4. Each TCU board handles two SNI-3/SNI-4 multiplexers in the direction towards the Switch and two SNI-4/SNI-3 demultiplexers in the direction from the Switch. TCU is triplicated, and all Devices with an SNI-3 interface can be connected to the Switch by means of a TCU. TAU 16x2 interfaces sixteen 2 Mbit/s plesiochronous line signals. The same TAU 16x2 is used both in AXD and SDH systems. Since as many as sixteen line signals are handled by one board, a protection function may be used. For every four active TAU 16x2 is it possible to have an additional standby TAU 16x2. All sixteen signals can be switched to this board when any one of the ordinary boards is faulty. TAU 16x2 contains three different ASICs. The protection function is controlled from the TCU and is performed by the Protection Switching Unit (PSU). The PSU has a minimum number of components and, hence, no UP. The PSU is supervised from theTCUs, Fig. 8. ERICSSON REVIEW No. 3, 1992
Page 1: ERICSSON REVIEW 3 1992 An Introduct
Page 4 and 5: An Introduction to the Ericsson Tra
Page 6 and 7: 60 Fig. 3 AXD 155 system integratio
Page 8 and 9: Control and Operation of SDH Networ
Page 10 and 11: 64 These functions and a number of
Page 12 and 13: 66 to the OS upon detection of a se
Page 14 and 15: 68 BOX 3 The SDH NE MANAGEMENT ORGA
Page 16 and 17: Fig. 4 Control System Architecture
Page 18 and 19: 72 Fig. 6 Software Architecture CSA
Page 20 and 21: 74 Functional requirements Certain
Page 22 and 23: 76 Fig 10 SMUX Control System Hardw
Page 24 and 25: AXD 4/1, a Digital Cross-Connect Sy
Page 26 and 27: 80 Fig. 2 AXD 4/1, System Architect
Page 28 and 29: 82 Fig. 3 Time Space Switch structu
Page 30 and 31: 84 Fig. 4 AXD 4/1 Devices Devices o
Page 34: 88 Fig. 8 Protection Switch Unit st

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