Purpose: To verify that the SUT detects link errors during the Link Confidence Test and will fail the LCT if too many link errors are detected.

References:

• SMT 6.2 section 9.4.6
• SMT 7.3 section 9.4.6

Resource Requirements:

• Testing Station to establish connections, to signal any duration of LCT, and to transmit link errors at various rates during the LCT.
• Passive Monitor to capture line states.

Discussion: Stations implementing SMT 6.2 shall fail the LCT if the link error rate is in excess of the LER_Cutoff value. Stations implementing SMT 7.3 shall fail the LCT if any link error has occurred.

Test Setup: Configure a ring with the Testing Station, the SUT and the Monitor (see figure). The Monitor is set up to capture line states.

For stations implementing SMT 6.2:

Procedure: The Testing Station attempts a connection, signalling LCT Extended and transmitting link errors at a rate of 1E-9 during the LCT. On the Monitor, note whether the SUT passed or failed the LCT (SIGNAL, n=7 = MLS for pass, HLS for fail). Repeat for error rates of 1E-8, 1E-7, 1E-6, 1E-5, and 1E-4. Repeat for all ports on the SUT.

Observable Results: The SUT must fail the LCT on the last error rate. For whichever rate the SUT fails the LCT, verify that all rates before pass and all rates after fail.

For stations implementing SMT 7.3:

Procedure:The Testing Station attempts a connection, transmitting a single link error during the LCT. Repeat for all ports on the SUT.

Observable Results: Verify that the SUT fails the LCT.

Possible Problems: None.