M40e MCS Components and LEDs
Each MCS (shown in Figure 1) has the following components:
- PCI interface—Connects the MCS to the Routing Engine.
- 100-Mbps Ethernet switch—Carries signals and monitoring data between router components.
- 19.44-MHz stratum 3 reference clock—Generates clock signal for SONET/SDH PICs.
- I2C controller—Monitors the status of router components.
- Three LEDs—Indicate MCS status. There is a blue one labeled MASTER, a green one labeled OK, and an yellow one labeled FAIL. Table 1 describes the LED states.
- Offline button—Prepares the MCS for removal from the router when pressed.
- Extractor clips—Control the locking system that secures the MCS in the chassis.
Figure 1: M40e Miscellaneous Control Subsystem

Table 1: States for M40e MCS LEDs
Label | Color | State | Description |
|---|---|---|---|
MASTER | Blue | On steadily | MCS is master. |
OK | Green | On steadily | MCS is functioning normally. |
Blinking | MCS is starting up. | ||
FAIL | Yellow | On steadily | MCS has failed. |
