4-6
OC12 Packet Over SONET Line Card Installation and Configuration
OL-3437-01
Chapter 4 Configuring the OC12 POS Line Card
Configuring the Interfaces
To verify that SONET payload scrambling is enabled on an interface, enter the show running-config
command. If scrambling is enabled, the following line is displayed in the configuration:
pos scramble-atm
To disable SONET payload scrambling, use the no pos scramble-atm command.
Configuring SONET Delay Triggers
A trigger is an alarm that, when asserted, causes the line protocol to go down. The following sections
discuss line triggers and path triggers, which you configure with the pos delay triggers command.
RTR12410-1(config)#
interface pos 1/0
RTR12410-1(config-if)#
pos delay triggers ?
line Specify delay for SONET LINE level triggers (S-LOS, S-LOF, L-AIS)
path Enable SONET PATH level triggers (P-AIS, P-RDI), with optional delay
RTR12410-1(config-if)#
pos delay triggers line ?
<0-511> Holdoff time, in msec
<cr>
Line and Section Triggers
The pos delay triggers line command is used for Internet router POS interfaces connected to
internally-protected Dense Wavelength Division Multiplexing (DWDM) systems. This command is
invalid for interfaces that are configured as APS working or protected. Normally, even a few
microseconds of line- or section-level alarms brings down the link until the alarm has been clear for ten
seconds. If you configure holdoff, this link-down trigger is delayed for 100 ms. If the alarm stays up for
more than 100 ms, the link is brought down as it is now. If the alarm clears before 100 ms, the link is
not brought down.
By default, the following line and section alarms are triggers for the line protocol to go down:
•
Section loss of signal (SLOS)
•
Section loss of frame (SLOF)
•
Line alarm indication signal (LAIS)
When one or more of these alarms is asserted, the line protocol of the interface goes down without a
delay. You can issue the pos delay triggers line command to delay triggering the line protocol of the
interface. You can set the delay from 50 to 10000 ms. If you do not specify a time interval, the default
delay is set to 100 ms.
Path Level Triggers
The following path alarms are not triggers by default. You can configure these path alarms as triggers
and also specify a delay.
•
Path alarm indication signal
•
Path remote defect indication
•
Path loss of pointer
•
B3 TCA alarms (starting in Cisco IOS Release 12.2(31)SB13
You can issue the pos delay triggers path command to configure various path alarms as triggers and to
specify an activation delay between 50 and 10000 ms. The default delay value is 100 ms, except for B3
TCA alarms.
