User Manual
Product information and planning
9500 MPR Rel. 3.1
3DB18809AAAA Issue 1128/980
The STM-1 unit can be used in two different working modes, addressing two different network scenarios:
– STM-1 channelized
– STM-1 transparent
The STM-1 channelized mode is available by provision the unit as "SDHCHAN" and the STM-1
transparent mode is available by provision the unit as "SDHACC".
The STM-1 unit can support 1 channelized STM-1 or up to 2 transparent STM-1 interfaces.
The STM-1 channelized
interface works as a terminal multiplexer; it terminates or originates the SDH
frame. It multiplexes NxE1 into an STM-1 electrical/optical line connection. The clock source can be “Loop
time” or “Node time”. Typical application is a direct connection to SDH add-drop multiplexers (ADMs).
STM-1 card manages one 155 Mbit/s STM1 interface and up to 63xE1. Standard VC4 mapping of lower-
order E1 traffic streams to/from STM-1 is applied, that means that a VC4 directly maps up to 63xVC12
into an STM-1 signal (in turn each VC12 contains 1xE1).
Link options include:
– 1+0 non-protected operation
– 1+1 EPS protection (available ONLY with the optical interface)
When the protection of the unit is required (1+1 EPS protection), two STM-1 units must be installed.
Clock source from the incoming STM-1 signal can be selected as Network Element source clock. In the
event the clock source is lost, clocking falls back to the internal clock or to other of any synch in options.
In the Tx direction, the STM-1 Local Access unit processes and encapsulates up to 2xSTM-1 input lines
into an Ethernet packet that is sent to the Core-E card(s).
In the Rx direction, the STM-1 Local Access unit extracts data from the Ethernet data packets and
processes the data to provide up to 2 STM-1 output lines.
The 2xSTM-1 Local Access Unit performs the following macro functions:
– Transparent or channelized transport of the STM-1
– Encapsulation/Extraction of the STM-1 into/from standard Ethernet packets Inter Working Function
– Reconstruction of the original STM-1 Timing
– Selection of the Active Core-E
– Sending/getting those std Eth packets to the Core-E module
– Communication with the Controller for provisioning and status report
The unit communicates with the Core-E modules through two GbEth Serial copper bi-directional
interfaces on the backplane.
Figure 46. STM-1 Access unit
Optional SFP (electrical or optical)
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