PLCP/Direct Mapping

Setting mapping to PLCP changes the effective speed of a DS3 interface to 40.704 M. When a port operates in a PLCP mode, the OCD events and LCD are not applicable (including related status fields and counters).

Similarly the below-defined PLCP statuses, alarms, and counters do not apply for direct mapped ports.

When a path operates in the PLCP mode, the router supports the standard ATM MIB monitoring of the PLCP operations, for example:

PLCP severely errored framing seconds
PLCP alarm state
PLCP unavailable seconds counter

Table 1 shows how SONET alarm status, path operational status, ATM interface and PLCP status and PLCP Alarm state interact.

Table 1. Alarm State Interactions
Content of the Received Signal						Status Field Values
Local Signal	Local Frame	Local Payld	Local PLCP Framing	Far End Framing	Far End PLCP Framing	Path Sonet Alarm Status	Path Oper Status	Atm Interface Oper Status	PLCP Alarm State
Y	Y	Y	Y	Y	Y	None	Up	Up	No Alarm
Y	Y	Y	Y	Y	Prob	None	Up	Lower Layer Down	Far End Alarm Rx
Y	Y	Y	Y	Prob	Prob	RDI	Down	Lower Layer Down	Far End Alarm Rx
Y	Y	Y	Prob	Y	N/A	None	Up	Lower Layer Down	Incoming LOF
Y	Y	Y	Prob	Prob	N/A	RDI	Down	Lower Layer Down	Incoming LOF
Y	Prob	N/A	N/A	N/A	N/A	LOF	Down	Lower Layer Down	Incoming LOF
AIS	N/A	N/A	N/A	N/A	N/A	AIS	Down	Lower Layer Down	Incoming LOF
Prob	N/A	N/A	N/A	N/A	N/A	LOS	Down	Lower Layer Down	Incoming LOF

A DS3 path configured for PLCP mapping:

Supports transmit and receive of the Ax, Px and C1 bits.
Ignores the received Z1, Z2, Z3 octets of the PLCP frame and transmits all zeros in the Z1, Z2, Z3 octets of the PLCP frame.
Ignores the received F1 octet of the PLCP frame, and transmits all zeros in the F1 octet of the PLCP frame.
Samples and uses for performance monitoring received FEBE bits of G1 octet and transmits the number of BIP-8 errors detected by the receive framer using the FEBE bits of the G1 octet. Detects a PLCP Far End Alarm when 10 consecutive PLCP frames are received with the RAI bit set, and transmits a set RAI bit when the local port has declared PLCP-LOF. When the local port declares PLCP-LOF is cleared, the outgoing RAI bit is cleared.
Ignores the received X bits of the G1 octet, and transmits all zeros in the X bits of the G1 octet of the PLCP frame.
Ignores the received M1 and M2 octets and transmits all zeros in the M1 and M2 octets of the PLCP frame.