4A0-205 Exam Dumps : Nokia Optical Networking Fundamentals

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

In theOptical Transport Network (OTN)hierarchy, theTTI (Trail Trace Identifier)is a 64-byte overhead signal used to ensure that the source and destination of a path are correctly connected. It is part of the overhead in theOTU (Optical Transport Unit)andODU (Optical Data Unit)layers. The TTI provides a mechanism for "path trace" to prevent misconnections. It specifically carries theSAPI (Source Access Point Identifier)and theDAPI (Destination Access Point Identifier).

These identifiers are strings that uniquely identify the source and destination ports. By comparing the "Expected SAPI/DAPI" configured on a port with the "Received SAPI/DAPI" actually coming in over the fiber, the Nokia 1830 PSS can detect fiber patching errors or cross-connect mistakes. If there is a mismatch, the system can trigger aTIM (Trace Identifier Mismatch)alarm and potentially squelch the traffic to prevent data from being delivered to the wrong customer. This is a Layer 1 (OTN) function and is entirely independent of Layer 2 MAC addresses or Layer 3 IP addresses used by the management system for DCN (Data Communication Network) connectivity.

The third window (1550 nm) is where the attenuation reaches its minimum peak. This is because the materials used in fiber optic cables have minimal absorption in this wavelength range. The first and second windows (850 nm and 1300 nm respectively) have higher attenuation due to the materials used in the fiber optic cables.

The NFM-T network map provides a graphical view of the network with different colors used to represent each node, physical connection, and active alarm. It allows the user to quickly identify any issues in the network and provides context sensitive navigation.