Connection verification

Connection verification checks the connection between the OLT-C line card and all the other passive modules to avoid miscabling during the node installation. This task generates a specific probe signal from the dedicated Connection Verification Tunable Laser (CV-TL) available at COM-RX-2 (at a given frequency and power) and detects the probe signal on:

• The same OLT-C line card

• The passive modules (Mux/Demux panel or breakout panel) connected to the OLT-C line card

• A different unit (OLT-C line card or passive module) belonging to the same NE

• An optical interface (Router ports or Transponder) connected to the OLT-C line card

Connection verification uses a probe signal or adds a low frequency ON/OFF modulation tone transmitting a given tone pattern at 5 Hz (200 ms bit time). The tone pattern length ranges 4–32 bytes (including an alignment byte) and it includes the Cable-IDs of the cables in the connection and in case also the optical frequency of the specific connection.

Note

The Connection Verification feature requires that 'tone-pattern' and 'tone-pattern-expected' be the same length.

The Cable-ID is generated by the Optical Node Controller supervising the complete NE.

The connection verification process uses the out-of-band (OOB) WSS frequencies (191.150–191.3375 THz) to reach the Optical Interfaces connected to the OLT-C line card via Mux/Demux panel.

This section describes the connection verification between OLT-C line card and passive modules that are connected to ADD/DROP-i ports and the association between each passive modules and the related OLT-C line card USB management port.

Connection verification is performed using the OOB channel with CV-TL tuned at 191.175 THz. To univocally identify the optical path under test, the CV-TL is modulated with a low-frequency pattern including the Cable-ID of the connection.

For connection verification toward Mux/Demux panel, the CV-TL at COM-RX-2 port is routed to the DROP-1 or DROP-2 ports. The CV-TL is checked at the PD 36 inside the Mux/Demux panel. CV-TL verifies the correspondence between the specific module and management USB port. The connection verification loopback performs verification of the full optical path. The loopback checks the connection verification signal at PD 24/25 filtered monitors available on OLT-C line card ADD-1 or ADD-2 ports.

To detect the tone pattern on the connection verification signal, these thresholds are set on the different monitors points:

• Mux/Demux panel at PD 36 ON-threshold = –3dBm

• Breakout panel loopback PD ON-threshold = –3dBm

• OLT-C line card ADD ports at PD 24/25 ON-threshold = –5dBm

• OLT-C line card COM-TX-2 port ON-threshold = –21dBm

For connection verification toward the breakout panels, the CV-TL at the COM-RX-2 port is routed to the first fiber of the specific MPO connector (port DROP-i with i=4, 12, 20, 28). The connection verification signal is checked at the monitors present in the breakout panels on the loopback path. This verifies the correspondence between the specific module and management USB port. The verification of the full optical path is performed by checking the connection verification signal at the COM-TX-2 port.

All the monitors receiving a connection verification signal detects and buffers the Cable-ID pattern encoded in the tone to allow the connection verification process by the node controller.

The connection verification signal loopback inside the breakout panel is replicated on all the output port on the MPO connector. In this way, it is possible to verify the loss of the MPO cable on the different fibers checking the connection verification signal power levels at the different ADD-i ports. This function requires a “diverse routing” between WSS Mux and Demux sections.

This section describes the connection verification between the different OLT units that are deployed on different sides of a multidegree ROADM node. The interconnection between the different OLT faced on the different sides of a multidegree ROADM is performed via LC patch-cords interconnection between the MPO ports of NCS1K-BRK-8 modules. This figure shows the Side-to-Side connection between the OLT nodes through NCS1K-BRK-8 modules.

1	EITU USB 2.0 Port
2	OLT-C Line Card Add/Drop MPO Ports
3	NCS1K-BRK-8 USB 2.0 Port
4	NCS1K-BRK-8 MPO Ports
5	NCS1K-BRK-8 LC Cable

The connection verification process is performed using the OOB channel with CV-TL tuned at frequency 191.17 THz. To univocally identify the optical path under test, the CV-TL is modulated with a low-frequency pattern including the Cable-ID of the connection.

The connection verification signal that is generated by the CV-TL is routed to the specific WSS DROP-i ports used for the side-to-side interconnection. It is verified at the monitors available at the NCS1K-BRK-8 input ports that are connected to the OLT-C line card at the other side.

All the monitors receiving a connection verification signal detects and buffers the Cable-ID pattern encoded in the tone. This method allows the proper connection verification process by the node controller.

The side-to-side connection verification is performed after the connection verification between the OLT-passive units to have a complete view of the interconnection between the OLT and each specific NCS1K-BRK-8 module.

The side-to-side connection verification check is performed without any traffic present on the path.

To properly detect the tone pattern on the side-to-side connection verification signal, an ON-threshold of –5dBm is provisioned on all PDs at the DIR-i-RX ports of the NCS1K-BRK-8 module.

This section describes the connection verification between OLT nodes and the optical interfaces that are connected to Mux/Demux panel and breakout modules.