SWITCHING, ROUTING, AND WIRELESS ESSENTIALS

Steven Odhiambo — Wed, 11 Dec 2024 05:18:04 +0000

Switch LED Indicators
The mode button is used to toggle through port status, port duplex, port speed, and if supported, the Power over Ethernet (PoE) status of the port LEDs

SYST – System LED – Shows whether the system is receiving power and is functioning properly. If off, the system is not powered on. If LED is green, the system is operating normally. If LED is amber, the system is receiving power but not functioning properly.
RPS – Redundant Power System LED – Shows the RPS status. If the LED is off, the RPS is off, or not properly connected. If the LED is green, the RPS is connected and is ready to provide backup power. If the LED is blinking green, the RPS is connected but is unavailable because it is providing power to another device. If the LED is amber, the RPS is in standby mode, or in a fault condition. If the LED is blinking amber, the internal power supply in the switch has failed, and the RPS is providing power.
STAT – Port Status LED – Indicates that the port status mode is selected when the LED is green (the default mode). When selected, the port LEDs will display colours with different meanings. If the LED is off, there is no link, or the port was administratively shutdown. If the LED is green, a link is present. If the LED is blinking green, there is an activity and the port is sending or receiving data. If the LED is alternating green-amber, there is a link fault. If the LED is amber, the port is blocked to ensure that a loop does not exist in the forwarding domain and is not forwarding data. If the LED is blinking amber, the port is blocked to prevent possible loop in the forwarding domain.
DUPLX – Port Duplex LED – Indicates that the port duplex mode is selected when the LED is green. When selected, port LEDs that are off are on half-duplex mode. If the LED is green, the port is in full-duplex mode.
SPEED – Indicates the port speed mode is selected. When selected, the port LEDs will display colours with different meanings. If the LED is off, the port is operating at 10 Mbps. If the LED is green, the port is operating at 100 Mbps. If the LED is blinking green, the port is operating at 1000 Mbps.
PoE – Power over Ethernet Mode LED – If PoE is supported, a PoE LED will be present. Off means PoE is not selected and none of the ports have been denied power or placed in a fault condition. Blinking amber means the PoE mode is not selected but at least one of the ports has been denied power or has PoE fault. Green indicates that PoE mode is selected, and the port LEDs will display colours with different meanings. Off means PoE is off. Port LED green means PoE is on. Port LED alternating green-amber means PoE is denied because providing power to the powered device will exceed the switch power capacity. Blinking amber means that PoE is off because of a fault. Amber means PoE for the port has been disabled.

SWITCHING, ROUTING, AND WIRELESS ESSENTIALS

Steven Odhiambo — Wed, 11 Dec 2024 05:12:07 +0000

Switch Boot Sequence
After a Cisco switch is powered on, it goes through the following five-step boot sequence:
Step 1: First, the switch loads a power-on self-test (POST) program stored in ROM. POST checks the CPU subsystem. It tests the CPU, DRAM, and the portion of the flash device that makes up the flash file system.
Step 2: Next, the switch loads the boot loader software. The boot loader is a small program stored in ROM that is run immediately after POST successfully completes.
Step 3: The boot loader performs low-level CPU initialization. It initializes the CPU registers, which control where physical memory is mapped, the quantity of memory, and its speed.
Step 4: The boot loader initializes the flash file system on the system board.
Step 5: Finally, the boot loader locates and loads a default IOS operating system software image into memory and gives control of the switch over to the IOS.

DEV Community: Steven Odhiambo

SWITCHING, ROUTING, AND WIRELESS ESSENTIALS

SWITCHING, ROUTING, AND WIRELESS ESSENTIALS