Network Troubleshooting: Ping, Discovery, IP Plans & Common Faults

Est. 55 minCompetency: Diagnose common AV network faults methodically.

Learning objectives

Use ping and device discovery to locate faults.
Read an IP plan to find a device.
Identify common faults: duplicate IP, wrong VLAN, PoE budget.
Apply a methodical fault-isolation order.

Vocabulary

Ping: ICMP echo test of reachability and latency.
Device discovery: Finding devices by broadcast/protocol (Dante, control).
Link/state LEDs: Port and device LEDs showing link and activity.
Duplicate IP: Two devices with the same address causing conflicts.

Lesson content

Network faults are systematic. Use the IP plan, ping, and discovery tools to isolate before guessing.

Methodical order

1Physical layer: is the cable seated? Link LED on? PoE delivering power?
2Addressing: is the IP correct, in the right subnet/VLAN, not a duplicate?
3Reachability: can you ping the device from the control side?
4Discovery: does the device show up in Dante/controller discovery?
5Application: is the route/subscription/clock correct?

Common faults

Duplicate IP — intermittent, random; check the IP schedule for two devices claiming the same address.
Wrong VLAN — device on the data VLAN, control on the AV VLAN; cannot reach each other.
PoE shortfall — device does not power up; check the switch's PoE budget and class.
IGMP off / EEE on — multicast video floods or Dante drops out.
Gateway missing/wrong — works locally, cannot reach other networks.

Read the plan first

Before any packet capture, read the IP schedule: most 'network' problems are a wrong address, wrong VLAN, or a device not on the plan at all.

Worked example

A touchpanel won't connect. Link LED is on but no discovery. Ping its IP — no reply. Check the schedule: it is on the corporate VLAN, control is on the AV VLAN. Move the port to the AV VLAN; the panel appears in discovery and connects.

Implementation checklist

✓Physical/link/PoE checked first.
✓IP, subnet, VLAN, and duplicate checked against the schedule.
✓Ping from the control side to confirm reachability.
✓Discovery confirms the device is present.
✓Application layer (route/subscription/clock) verified last.

Downloadable study guide

study-guide.txtcopy-paste ready

01. Troubleshoot bottom-up: physical → addressing → reachability → discovery → application.
02. Common faults: duplicate IP, wrong VLAN, PoE shortfall, IGMP off, EEE on, missing gateway.
03. Read the IP schedule before deeper tools.
04. Ping confirms reachability; discovery confirms the device is alive.