This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
STP, RSTP, and MSTP stop a loop by blocking a port. RSTP is faster to reconverge. MSTP maps VLANs onto instances so you do not need one tree per VLAN. The simulator helps you see a topology you type. It does not configure a switch.
One mode on the switches that share the VLANs. A port that is a trunk of every VLAN, plus a blocked port you did not expect, is how an outage hides. Write the root you intend. Do not change the root during the reading.
The switches are ones you administer. A neighbor's switch is not a root you seize.
The change you can finish
Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.
Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.
- Name the switches.
- Pick one mode.
- Name the root you intend.
- Write which port should block.
- Do not change the switches.
- Stop.
Mistakes that outlive the command
STP vs RSTP vs MSTP goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Two modes on one VLAN.
- Seizing root from a switch you do not administer.
- Allowing every VLAN across a trunk to finish the drawing.
- Changing the root during the reading.
Decisions to write down
One decision for STP vs RSTP vs MSTP: One mode is chosen. The root is a switch you administer. The blocked port is a guess you labeled. Nothing was changed. And the trunk list is not every VLAN by default.
Checks before you call it done
Confirm this before you call the change done: The mode is written. The root is written. The switches are yours. No switch was changed. And a second mode is absent. If one of those fails, stop.
| Mode | What you are accepting |
|---|---|
| STP | Slow timers. Fine only if the platform gives you nothing else. |
| RSTP | Faster reconvergence. One tree. |
| MSTP | VLANs grouped into instances. Map them on purpose. |
Before you leave the device
STP vs RSTP vs MSTP ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.
0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.
One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied config produces a device nobody can rebuild. Restore the copy you took first.
A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.
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