363-206-295
Administration and Provisioning
Issue 1
December 1997
8-7
Multiplexing and Mapping
8
The following paragraphs describe DS3 to OC-12, OC-3 to OC-12, EC-1 to
OC-12, and OC-3c to OC-12 (feature package option) multiplexing and mapping.
DS3 to OC-12
8
Each DS3 signal received by a 3DS3 circuit pack is mapped to an STS-1 signal
via the asynchronous mapping as specified in the SONET standard. The three
STS-1 signals associated with a 3DS3 circuit pack are then multiplexed with the
STS-1 signals from the other function units to form the STS-12 high-speed signal.
The STS-12 signal is then converted to an OC-12 signal for transport on the high-
speed optical line.
In the reverse direction, a received OC-12 signal is converted to an electrical
STS-12 signal which is demultiplexed to 12 STS-1 signals. The STS-1 signals are
routed to the function units where they are converted back into DS3 signals by the
3DS3 circuit packs.
OC-3 to OC-12
8
When a function unit is equipped with a 21-type OLIU circuit pack, the received
optical signal is converted to an electrical STS-3 signal which is demultiplexed into
three STS-1 signals. The three STS-1 signals are multiplexed with the STS-1
signals from the other function units to form an STS-12 signal, which is converted
to an OC-12 signal for transport on the OC-12 line.
In the reverse direction, the received OC-12 signal is converted to an electrical
STS-12 signal which is demultiplexed to 12 STS-1 signals. The STS-1 signals are
routed to the function units where they are multiplexed to an STS-3 signal, which
is converted to an OC-3 optical signal for transport on the optical line.
When the function unit service and protection slots are equipped with OLIUs, they
can be provisioned as ring (0x1) low-speed interfaces or linear (1+1) optical
extensions using the
set-oc3
command. The cross-connections can then be
made using the
ent-crs-sts1
command. See Section 11, "Commands and
Reports," for more information on this provisioning.