What is the difference between GLC-SX-MM-RGD and GLC-SX-MMD?
The main difference is the operating temperature.
Cisco GLC-SX-MMD: 0 to -70℃ (COM);
Commercial operating temperature range;
Cisco GLC-SX-MM-RGD: -40 to -85℃ (IND);
Industrial operating temperature range;