28-08-2014, 02:44 PM
STM stands for Synchronous Transport Module.This is the information structure used to support information payload and over head information field organised in a block frame structure which repeats every 125 microseconds.The bit rate of STM-1 is 155.520Mbps. The standardized SDH transmission frames, called Synchronous Transport Modules of Nth hierarchical level (STM-N). A frame with a bit rate of 155.52 Mbit/s is defined in ITU-T Recommendation G.707. This frame is called the synchronous transport module (STM). Since the frame is the first level of the synchronous digital hierarchy, it is known as STM-1.
Frame Format SECTION OVERHEADS: RSOH (regenerator section overhead) The Regenerator Section OverHead uses the first three rows & nine columns in the STM-1 frame. A1, A2The Frame Alignment Word is used to recognize the beginning of an STM-N frame J0 Path Trace. It is used to give a path through an SDH Network a "Name". This message (Name) enables the receiver to check the continuity of its connection with the desired transmitter B1 Bit Error Monitoring. The B1 Byte contains the result of the parity check of the previous STM frame, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check. E1-Engineering Orderwire (EOW). It can be used to transmit speech signals beyond a Regenerator Section for operating and maintenance purposes. One 64kb/s channel is reserved for EOW. F1 User Channel. It is used to transmit data and speech for service and maintenance D1 to D3 Data Communication Channel at 192 kbit/s (DCCR). This channel is used to transmit management information via the STM-1 frames MSOH (multiplex section overhead) The Multiplex Section OverHead uses the 5th through 9th rows, and first 9 columns in the STM-1 frame. B2 Bit Error Monitoring. The B2 Bytes contains the result of the parity check of the previous STM frame, except the RSOH, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check (BIP24) K1, K2 Automatic Protection Switching (APS). In case of a failure, the STM frames can be routed new with the help of the K1, K2 Bytes through the SDH Network. Assigned to the multiplexing section protection (MSP) protocol K2 (Bit6,7,8) MS_RDI Multiplex Section Remote Defect Indication (former MS_FERF Multiplex Section Far End Receive Failure) D4 to D12 Data Communication Channel at 576 kbit/s (DCCM) Introduction of SIEMENS COMPACT 155 MBIT/S ADD-DROP MULTIPLEXER SURPASS hiT-1/4E P5.3 The SURPASS hiT-1/4E is an optical STM-1/STM-4 add-drop multiplexer used to build STM-1/STM-4 point-to-point links, STM-1 or STM-4 rings, or mesh networks with conduct (SNC) or STM-1 line (MSP) protection, so performing the conveyance of 2 Mbit/s, 34 or 45 Mbit/s PDH links, of 155 Mbit/s STM-1 SDH links, of 10/100 Mbit/s Ethernet links. From P5.3 release, the STM-1 cards offer extractable interfaces SFP (Small Form Factor Pluggable), also integrating DDM (DIGITAL Diagnostic Monitoring) function. The SURPASS hiT-1/4E can be used as : STM-1 terminal multiplexer with maximum capacity of 63 VC12 and capability of 1+1 protection. STM-1 repeater, capability of regenerating 2 VC4, STM1 multiplexer with insertion/extraction, with maximum capacity of switching of 4 STM-1 more 21 VC12, STM-4 ADD/DROP multiplexer with capacity of 63 VC12 over one AU4 per STM-4 card. LAN over VC12 or VC3 interconnection point (via 4E/FE). The 4E/FE data traffics are compatible with those of the SURPASS hiT-16.
Frame Format SECTION OVERHEADS: RSOH (regenerator section overhead) The Regenerator Section OverHead uses the first three rows & nine columns in the STM-1 frame. A1, A2The Frame Alignment Word is used to recognize the beginning of an STM-N frame J0 Path Trace. It is used to give a path through an SDH Network a "Name". This message (Name) enables the receiver to check the continuity of its connection with the desired transmitter B1 Bit Error Monitoring. The B1 Byte contains the result of the parity check of the previous STM frame, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check. E1-Engineering Orderwire (EOW). It can be used to transmit speech signals beyond a Regenerator Section for operating and maintenance purposes. One 64kb/s channel is reserved for EOW. F1 User Channel. It is used to transmit data and speech for service and maintenance D1 to D3 Data Communication Channel at 192 kbit/s (DCCR). This channel is used to transmit management information via the STM-1 frames MSOH (multiplex section overhead) The Multiplex Section OverHead uses the 5th through 9th rows, and first 9 columns in the STM-1 frame. B2 Bit Error Monitoring. The B2 Bytes contains the result of the parity check of the previous STM frame, except the RSOH, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check (BIP24) K1, K2 Automatic Protection Switching (APS). In case of a failure, the STM frames can be routed new with the help of the K1, K2 Bytes through the SDH Network. Assigned to the multiplexing section protection (MSP) protocol K2 (Bit6,7,8) MS_RDI Multiplex Section Remote Defect Indication (former MS_FERF Multiplex Section Far End Receive Failure) D4 to D12 Data Communication Channel at 576 kbit/s (DCCM) Introduction of SIEMENS COMPACT 155 MBIT/S ADD-DROP MULTIPLEXER SURPASS hiT-1/4E P5.3 The SURPASS hiT-1/4E is an optical STM-1/STM-4 add-drop multiplexer used to build STM-1/STM-4 point-to-point links, STM-1 or STM-4 rings, or mesh networks with conduct (SNC) or STM-1 line (MSP) protection, so performing the conveyance of 2 Mbit/s, 34 or 45 Mbit/s PDH links, of 155 Mbit/s STM-1 SDH links, of 10/100 Mbit/s Ethernet links. From P5.3 release, the STM-1 cards offer extractable interfaces SFP (Small Form Factor Pluggable), also integrating DDM (DIGITAL Diagnostic Monitoring) function. The SURPASS hiT-1/4E can be used as : STM-1 terminal multiplexer with maximum capacity of 63 VC12 and capability of 1+1 protection. STM-1 repeater, capability of regenerating 2 VC4, STM1 multiplexer with insertion/extraction, with maximum capacity of switching of 4 STM-1 more 21 VC12, STM-4 ADD/DROP multiplexer with capacity of 63 VC12 over one AU4 per STM-4 card. LAN over VC12 or VC3 interconnection point (via 4E/FE). The 4E/FE data traffics are compatible with those of the SURPASS hiT-16.