Maintenance Description
9-54 Issue 8.0 July 2002
Optical Low Speed Protection Switching
Architecture 9
Figure 9-15 shows the optical low-speed protection switching architecture.
Figure 9-15. Optical Low Speed Protection Switching
Optical low-speed protection switching is only performed in the add (OC-12 to
OC-48) direction by an FT-2000 OC-48 Add/Drop-Rings Terminal. If the active
OC-12 line fails in the add (OC-12 to OC-48) direction, the board controller on the
OC12 (1.3 STD) circuit pack sends the information to the LNCTL circuit pack via
the BCLAN. If appropriate, the LNCTL circuit pack broadcasts a switch request to
the board controller on the OC48 TRMTR circuit pack. The board controller on the
OC48 TRMTR circuit pack activates the selector circuitry to choose the 155 Mb/s
signal from the standby OC12 (1.3 STD) circuit pack. The standby OC12
(1.3 STD) circuit pack becomes the new active OC12 (1.3 STD) circuit pack.
In the drop (OC-48 to OC-12) direction, the OC48 RCVR circuit pack routes the
same 155 Mb/s signal to the active and standby OC12 (1.3 STD) circuit packs.
nc-ft2000-038
OC12
1 0C-12
Low Speed
Signal
Control
Transmission
OC48 TRMTR
OC48 RCVA
BCLAN
LNCTL
LCLAN
SYSCTL
SYSMEM
OC12
OC48
1 0C-12
Low Speed
Signal
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