Question
Why do I get an error when configuring port mirroring across certain ports on an MCSESM203F4LG0 switch, and how can I enable mirroring?

Answer:

1. Issue

   Configuring port mirroring on MCSESM203F4LG0 fails with error message: "TX mirroring across unit boundaries is not supported"

2. Product Line

   • Hardware: MCSESM203F4LG0
   • Software Version (SV): 8.7.10

3. Resolution

   Port mirroring on this model is limited to a single switching chip. Mirroring across the two internal chips is not supported—this is a hardware limitation.

   The MCSESM203F4LG0 has two internal switching chips:

   • Chip 1: Ports 1/1 to 1/12
   • Chip 2: Ports 1/13 to 1/20

   To resolve:

   • Ensure that the mirror destination (primary/monitor port) and all mirror source ports (TX/RX) are on the same chip.
     • Example: Choose the monitor port from 1/1–1/12 and only select mirror sources within 1/1–1/12; do not include ports from the other chip.

4. FAQ Applicable Conditions

   • This FAQ remains valid unless a new hardware revision explicitly adds cross-chip mirror support.