The Hands-On Guide to Installing a Switch

From box to blinking green: installing your switch made simple.

First Listen: let your ears lead the way before your mind takes notes.

Then read: let your eyes explore before your mind starts to explain.

Physical Installation & Startup of a Switch

You’ve got the switch, the cables, and the space. That’s all you need to begin. Now it’s time to bring it to life — step by step, we’ll plug it in, power it up, and make sure those green lights shine. Don’t worry, you don’t need to be an expert; just follow along and your Catalyst switch will be ready for action in no time.

Step 1: Set the Stage

Before touching the switch, look around.

• Is the rack or shelf ready?
• Do you have enough space for air to flow around it? (At least a couple of inches.)
• Is the room cool, clean, and not humid?
• Is there a stable power outlet, preferably a UPS?

Think of this as “setting the stage” before the main actor (your switch) comes in.

Step 2: Give It a Quick Checkup

Take the switch out of the box (or storage) and inspect it.

• Any scratches, bent ports, or missing parts?
• Do you see the serial/model labels?
• Got the brackets, screws, and power cables?

Better to catch issues now than when it’s already bolted into the rack.

Step 3: Ground First, Always

Find the grounding lug on the back.

• Connect a thick copper wire (14-AWG or thicker) to the building’s ground or rack bar.
• Tighten it so it’s not loose.

Think of grounding as the seat-belt: you hope you never need it, but it keeps your switch safe from electrical accidents.

Ref: Cisco document

Step 4: Mount It in Place

Now you decide where it lives:

• If it’s going in the rack → attach the side brackets, slide it in, screw it tight.
• If it’s just sitting on a shelf → stick the rubber feet on and place it neatly.
• If it’s part of a stack → connect the stack cables now, before power.

This keeps the switch stable and ensures airflow is not blocked.

Step 5: Plug in Only Power

Grab the power cord and connect it to the switch, then to the outlet.

• If it has two power supplies, connect both.
• Don’t touch the Ethernet cables yet — keep it isolated for now.

Why? Because a used switch might still have VLANs, IPs, or STP configs that could cause loops if you connect it blindly.

Step 6: Talk to the Switch (Console Connection)

Connect your laptop with the blue console cable (RJ-45-to-USB, or USB console).

• Fire up PuTTY or Tera Term.
• Settings: 9600 baud, 8N1, no flow control.

The console is like sitting in the pilot’s seat — you see everything as it happens.

Step 7: Power On & Watch the Show

Turn it on (or just plug it if no switch).

• Fans roar first, LEDs blink.
• This is the POST (Power-On Self-Test).
• System LED goes green if all is good, amber if something failed.

That green light is your “all systems go.”

Step 8: IOS Boot Time

On your console screen, you’ll see IOS loading.

• Memory check → Flash check → IOS image loading.
• Once you get the Switch> prompt, you’re in.
• Type:
  • Switch> enable
• Now you’re the boss.

IOS is the switch’s brain, and you’re watching it wake up.

Step 9: Peek at What’s Inside

Since this isn’t a brand-new switch, check what’s saved:

• Startup config:
  • Switch# show startup-config
• VLANs:
  • Switch# show vlan brief
• Version and hardware:
  • Switch# show version

Think of this as checking the fridge before cooking — see what’s already in there.

Step 10: Clean Slate or Keep It?

If you want to start fresh, wipe it:

Switch# write erase
Switch# delete vlan.dat
Switch# reload

If you need to keep the old configs, back them up first.

Don’t bring old baggage into your shiny new network unless you mean to.

Step 11: Now Connect the Network Cables

Finally, plug in your Ethernet cables:

• PCs, printers, and servers → straight-through cables.
• Other switches/routers → crossover if it’s old gear, but most Catalysts use Auto-MDIX so straight-through works fine.
• Fiber uplinks → slide in your SFP/SFP+ and patch cord.

Check the port LEDs — flashing green means traffic is flowing.

Step 12: Quick Health Check

Run a few commands to confirm it’s happy:

• Interfaces:
  • Switch# show ip interface brief
• Hardware:
  • Switch# show inventory
• Fans, temperature, power:
  • Switch# show environment all

This is like a doctor’s checkup — make sure it’s breathing fine before you leave.

Final Recap (Easy to Remember)

Summary

[Return to CCNA Study Hub] — Next Stop: [Section 2 | Console Access]