SW-CTL (Switch Control)
Issue 4 May 2002
10-1571 555-233-123
SW-CTL (Switch Control)
The Switch Control resides on the TN2401/TN794 NetPkt (or TN777B Netcon)
circuit pack. Standard systems have a single NetPkt circuit pack and High and
Critical Reliability systems have a NetPkt circuit pack in each SPE complex. The
NetPkt in a standard system cannot be replaced without bringing the system
down. The NetPkt in the standby SPE of a High or Critical Reliability system can
be changed without affecting normal system operation.
The Switch Control is used to send control information between port circuit packs
and the processor. This control information is sent through the PPN cabinet’s
Time Division Multiplex (TDM) Bus. The portion of the TDM Bus used to transmit
control messages is called the control channel. The control channel can be on
either TDM Bus A or TDM Bus B, but only one bus is used for the control channel
at any given time.
The TN2401/TN794 provides LAPD connections over the TDM bus, as currently
provided by the Processor Interface (TN765). When reusing the existing control
carrier, the NETCON (TN777B) and PACCON (TN778) circuit packs are removed
and replaced by the Network Control/Packet Control Assembly, which consists of
the NetPkt circuit pack (TN2401/TN794) inserted into the NETCON slot and the
Net/Pak Backplane Connection (TN4200) inserted into the PACCON slot.
Upgrades involving new control carriers use the TN2401/TN794 only. Duplicated
R8si systems require two of the TN2404/TN790 cards preloaded with 16M DRAM
and the program card with R8 software, two TN792 DUPINTS, two sandwich
boards (TN2401/TN794 NetPkts and TN2400 combination), and optical cables.
The Switch Control is critical in the setup and take down of all calls but is not
involved in the voice or data transmission that takes place during established
calls. It is the Switch Control that detects when port circuit packs are plugged into
or removed from the PPN cabinet. This information is then sent to the processor.
The Switch Control monitors the health of the control channel on the PPN cabinet
TDM Bus and informs the processor when errors occur.
The Switch Control contains the hardware Time of Day (TIME-DAY) clock that the
system uses for all its date and time information. In addition, the Switch Control
also contains hardware to monitor critical system timing signals and informs the
processor when these signals fail. For example, if the timing signals from a
Tone-Clock circuit pack in the PPN cabinet fail, the Switch Control informs the
processor.
MO Name (in
Alarm Log)
Alarm
Level Initial Command to Run Full Name of MO
SW-CTL MINOR test network-control a sh Switch Control
SW-CTL MAJOR test network-control a sh Switch Control