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CHAPTER 6 PHY FUNCTION
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6.3 OAM INFORMATION CONTROL FUNCTION
The
μ
PD98405 has an OAM (Operation And Maintenance) function that is used to maintain and monitor the
network. This section explains the OAM function supported by the
μ
PD98405.
6.3.1 Transmission OAM Control
(1) Transmitting an alarm
The
μ
PD98405 transmits an alarm by writing it into a specific overhead area of the transmit frame.
Table 6-5. Transmitting an Alarm
Alarm
Transmission method
Line AIS/Path AIS
Transmitted or canceled by a command
Line RDI
Path RDI
Transmitted or canceled by a command
Automatically transmitted upon occurrence
of internal cause
(Automatic transmission can be masked.)
Line FEBE/Path FEBE
Automatically generated internally
(a) Transmitting Line AIS (Line Alarm Indication Signal)
Line AIS is a line alarm indication signal that reports, to units downstream, that a fault has been
detected upstream and that an alarm has been issued.
The
μ
PD98405 changes the sixth through eighth bits of the K2 byte of the transmit frame to "111" and
sets the bits of all areas other than SOH to "1" (before scrambling) for transmission if the LAIS bit of
command register 1 (PCMR1) is set to 1. Whether Line AIS is transmitted or transmission is canceled
is determined by the user.
Transmit overhead:
K2 byte (6th through 8th bits) = 111, and areas other than SOH =
1
Transmission/cancellation condition: The host controls the transmission or cancellation of
transmission according to the setting of the LAIS bit of command
register 1 (PCMR1).