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In the example that follows, the first port on an FSIP in interface processor slot 0 is configured for
CRC-4:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# interface serial 0/0
Router(config-if)# crc4
Ctrl-Z
To disable CRC and return an interface to the default of no CRC error checking, specify the interface
and use the no crc4 command.
Configuring E1-G.703/G.704 Clock Source
The E1-G.703/G.704 interface does not operate in the DTE and data communications equipment
(DCE) modes that are typical of data communications interfaces. The E1-G.703/G.704 interface
operates with either a line-recovered or an internal clock signal. The default is for a line clock signal
that the interface recovers from the received data stream. The interface can also operate with an
internal clock signal. The E1-G.703/G.704 port adapter generates the internal clock signal; the
interface does not use the FSIP clock.
We recommend that you leave one port on each module shut down to avoid exceeding the
6.132 Mbps maximum for each module because the E1-G.703/G.704 interfaces operate at a default
clock rate of 2.048 Mbps (E1 speed).
To specify the clock source, use the clock source {line | internal} command. To change the default
and use the internal clock, use the clock source internal command. To return the interface to the
default state, use the clock source line command. (The no clock source internal command also
returns the interface to the default state.)
Interpreting E1-G.703/G.704 Alarms
The following defines and describes the five alarms used with the E1-G.703/G.704 interface:
•
AIS—The alarm indication signal occurs and a failure is declared (for E1 links) when 64
consecutive ones occur on the Receive Data (RD) line between the applique and the FSIP.
•
RAI—The remote alarm indication (also called the far end alarm and distant alarm for E1 links)
is sent by the remote end of the link to indicate failure at the remote end. This failure is declared
(for E1 links) when 32 contiguous pulse positions have no pulses of either positive or negative
polarity.
•
LOS—The loss of signal alarm occurs and a failure is declared (for E1 links) when more than ten
consecutive zeroes are detected.
•
LOF—The loss of frame alarm occurs and a failure is declared (for E1 links) when an
out-of-frame (OOF) defect has persisted for T seconds, where 2 T 10. This f ailure is cleared
when there have been no OOF defects during a period T seconds, where 0 T 20.
•
SQ—The signal quality alarm occurs and a failure is declared (for E1 links) when the bit error
rate (BER) is greater than 10
–3
on the RD line between the applique and the FSIP.
Fast Serial Interface Processor (FSIP) Installation and Configuration
Configuring the FSIP
43
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