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Configuring the WAN Physical Link
Red, Blue, and Yellow Alarms
WAN links have error detection built into the link hardware. The hardware can detect
different types of errors, labeled red, blue and yellow alarms.
A red alarm occurs when the signal is lost or an out of frame error occurs. An out of
frame error can be caused when the framing type configured for the local interface does
not match the framing type of the incoming signal or when the incoming signal does
not contain a framing pattern.
A yellow alarm is also called a Remote Alarm Indication (RAI). When the remote end of
a link does not receive a signal, it will transmit a yellow alarm signal back to the local
end.
A blue alarm is also called an Alarm Indication Signal (AIS). A blue alarm indicates that
a device somewhere upstream has experienced a loss of signal.
Alarms affecting a link can be viewed by using one of the show commands, for
example,
.
show ports t1 alarms
Configuring WAN Physical Links
There are a number of parameters that can be configured for a WAN link. If you have
control of both sides of the link, then the default configuration is probably the best
choice. If you must connect to a line controlled by another organization, you will need
to configure the line to correspond with the settings at the other end. Some parameters
are only configurable, or only apply to some of the WAN link types. The following list
of parameters also displays which types of WAN links allow you to configure that
parameter:
• Cable length (T1, T3)
• Clock Source (T1, E1, T3)
• Facility Data Link (T1)
• Framing (T1, E1, T3)
• Inband Loopback Detection (T1)
• Linecoding (T1)
• Receiver Gain (E1)
• SNMP Alerts (T1, E1, T3)
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WAN Module Installation and User Guide
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