CCNA R&S

[deanwebb]

101 is retired. 105 is the current version.

I'm also planning some labs, as well, to go with the questions I'm writing. These promise to be fun as well as real-world relevant. I don't like learning for the sake of just passing a test, but for true understanding. We need labs like:

1. Set up a switch with 2 or 3 hosts in the same VLAN.
2. Ping one host from the other.
3. Take an ethernet cable and plug both ends of it into the switch.
4. Try and ping now. Hahahaha. You can't, can you?
5. Console in to the switch and see if it can ping the hosts connected to it.
6. Are any lights on the switch flashing that shouldn't be flashing? Are there any lights flashing in a way that seems unusual?
7. Unplug one end of the ethernet cable.
8. Things should be working fine now, verify with ping tests.
9. Plug as many switches together as you like, adding a few hosts to each switch. Do ping tests to make sure everybody's happy.
10. Now plug that other end of the ethernet cable back into the switch.
11. Everything went down, am I right?
12. What is going on, here?

In fact, I'mma post that lab right now...

[ggnfs000]

3. Take an ethernet cable and plug both ends of it into the switch.
This would be interesting experiment, IMO. I think devices connected to hubs will handle it gracefully with CSMA/CD   but switch b-storm? or it might just blow up.

[wintermute000]

hubs will just melt down. This is a classic from the early 2000s.
A switch with portfast/bpduguard will err-disable. A switch with non-portfast but valid STP will go through the standard STP states and end up blocking one end. A switch with misconfigured STP or no STP will melt down like a hub.

source: been there, done that, seen it all before numerous times in MSP land.

[deanwebb]

hubs will just melt down. This is a classic from the early 2000s.
A switch with portfast/bpduguard will err-disable. A switch with non-portfast but valid STP will go through the standard STP states and end up blocking one end. A switch with misconfigured STP or no STP will melt down like a hub.

source: been there, done that, seen it all before numerous times in MSP land.

EXACTLY the reason the kids out there need to do a lab like this!