Review the layers that carry business calls

Choose one representative phone at each distinct site. Confirm the access port and VLAN, current lease, gateway and call-server lookup against the approved diagram.

The layers that carry business calls

1. Compare the current firewall and route path with recent changes. Place a controlled call and record whether registration, setup and two-way audio pass.
2. Rotate the sample each month so one healthy phone does not stand in for every access switch or handset group.

Assign any mismatch to the owner of the relevant layer and retain the observed values, not just a pass or fail label.

Carry the result forward

Do not let an old diagram become the only evidence. Attach the date and source of each observed setting so a later reviewer can tell a live value from an intended one. Changes to switching, DNS and the PBX should be recorded separately.

See the Networking layers for voice troubleshooting when updating the service record.