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
The MAC table remembers which port owns an address. TCAM holds lookups such as routes and ACLs. The estimators turn counts you type into a sketch. They do not read the switch and they do not generate addresses. A full table means unknown unicasts are flooded, or new entries are dropped. Write which.
Use counts from a switch you administer, or label the numbers as a plan. Do not harvest addresses to fill the estimator, and do not create hosts to overflow the table.
One switch. A larger table is a purchasing note, not a command.
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.
- Write the current count or the planned count.
- Write the table size.
- Read the headroom.
- Say what a full table does on this platform.
- Do not generate MACs.
- Stop.
Mistakes that outlive the command
MAC Address Tables and TCAM Explained goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Harvesting addresses.
- Overflowing the table as a test.
- A size from a switch you do not administer presented as fact.
- Buying hardware during the reading.
Decisions to write down
One decision for MAC Address Tables and TCAM Explained: The numbers are yours or labeled as a plan. Headroom is written. Full-table behavior is named. No addresses were harvested. And nothing was purchased.
Checks before you call it done
Confirm this before you call the change done: The count is written. The size is written. The headroom is written. The full-table behavior is written. And no test hosts were created. If one of those fails, stop.
Before you leave the device
MAC Address Tables and TCAM Explained 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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