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
A T1 is about 1.5 Mbit/s. An E1 is about 2 Mbit/s. SONET and SDH bundle those ideas into larger optical rates. The reference lists the names. It does not order a circuit and it does not loop a live span. If you still operate one, write the provider and the far end.
A new design does not start here. This page explains a circuit you already have, or the name in an old diagram. Do not scramble a live circuit to see the alarm.
One circuit, or one name in a drawing. The replacement, if any, is a later plan.
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 circuit or mark it as a diagram.
- Read the rate.
- Write the far end if you operate it.
- Do not loop a live span.
- Do not order a new one.
- Stop.
Mistakes that outlive the command
Legacy Circuits: T1, E1 and SONET goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- A new build that starts with a T1.
- Looping a live circuit.
- A rate memorized wrong and then ordered.
- A circuit you do not administer described as yours.
Decisions to write down
One decision for Legacy Circuits: T1, E1 and SONET: The rate is read from the reference. A live circuit was not looped. Nothing was ordered. The far end is yours or the note says it is a diagram. And a replacement waits.
Checks before you call it done
Confirm this before you call the change done: The name is written. The rate is written. Live or diagram is written. No loop was placed. And no circuit was ordered. If one of those fails, stop.
Before you leave the device
Legacy Circuits: T1, E1 and SONET 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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