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
PIM builds a tree toward a rendezvous point for groups that do not yet have a shorter path. The planner drafts the RP address and the group. It does not configure a router and it does not send multicast. The RP has to be a router you administer, and the group has to be one your application uses.
Link-local groups are not routed to an RP. A dense flood of every group is the design you are not choosing. One group. One RP.
Do not enable PIM during the reading.
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 group your application uses.
- Name the RP.
- Keep link-local groups off the RP.
- Write sparse, not a flood.
- Do not enable PIM.
- Stop.
Mistakes that outlive the command
Multicast Routing and PIM Explained goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- An RP you do not administer.
- Every group mapped to the RP.
- A flood to test the tree.
- Enabling PIM during the reading.
- Routing 224.0.0.0/24.
Decisions to write down
One decision for Multicast Routing and PIM Explained: The group is yours. The RP is yours. The mode is sparse. Nothing was enabled. And no traffic was sent.
Checks before you call it done
Confirm this before you call the change done: The group is written. The RP is written. Link-local is excluded. PIM was not enabled. And no flood was sent. If one of those fails, stop.
Before you leave the device
Multicast Routing and PIM 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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