“What exactly does Engage do with IGMP?
What do ‘Planned Querier’ and ‘Election Participate’ really mean?
And why does a switch with a lower IP address still become the querier, even when I’ve checked ‘Planned Querier’ in Engage?”

This second blog is the practical answer to his question.
In Blog 1, I explained all the necessary background: what IGMP does, how the querier election process works, and why NETGEAR created IGMP Plus.
That context is essential to understanding why Engage behaves the way it does.

Now, let’s look specifically at Engage.

How NETGEAR Engage Handles IGMP

NETGEAR Engage is the central platform for configuring and monitoring AV networks built on M4250, M4300, M4350, and M4500 switches.
It makes complex networking tasks dramatically simpler and offers visual insight into multicast behavior.

But Engage does not change how the IGMP protocol works.
Engage provides a friendlier interface — not a different protocol.

Which IGMP Settings Can You Configure in Engage?

1. IGMP Snooping per VLAN

Engage allows you to enable or disable IGMP Snooping on a per‑VLAN basis.

In AV networks, IGMP Snooping is almost always enabled, because:

• Without snooping → uncontrolled multicast flooding
• With incorrect snooping → unpredictable behavior
• With proper snooping → clean, efficient multicast forwarding

Engage makes this easy and visually transparent.

2. Querier Settings per VLAN

Engage displays:

• Whether the local switch can act as querier
• Whether a querier is active in that VLAN
• Which IP address is being used to send IGMP queries

You can allow or disallow querier capabilities per VLAN, but the important rule remains:

Querier election is always decided by IGMP itself — the switch with the lowest IP address wins.

Engage does not override this.

3. “Election Participate” Setting

This setting determines how the switch behaves during a querier election:

• ON → the switch participates in the election and will win or lose based on its IP address
• OFF → the switch automatically becomes a non‑querier whenever another querier is detected

In larger networks you typically use:

• Election Participate = ON on the core (preferred querier)
• Election Participate = OFF on edge switches (to avoid accidental querier elections)

This gives predictable behavior.

4. “Planned Querier” — What It Actually Means

This was one of Jeroen’s key questions.

Here’s the crucial point:

“Planned Querier” in Engage is not a technical setting.
It does not modify the actual IGMP configuration of the switch.
It is purely a UI indicator inside Engage.

Its purpose:

• To mark the switch you intend to be the querier
• To visually check whether that switch is indeed acting as the active querier

This is extremely useful because:

• If the “planned” querier is not the actual querier, Engage immediately highlights the discrepancy
• That helps detect issues such as:
  • Incorrect IP planning
  • Multiple queriers
  • Wrong VLAN interface addresses
  • Misconfigured Election Participate settings

Engage makes these problems visible, but “Planned Querier” does not force anything at protocol level.

5. IGMP Monitoring within Engage

Engage provides highly valuable real‑time insights, including:

• Current querier IP
• Querier operational state
• IGMP membership lists
• IGMP report activity
• IGMP Plus status
• Alerts when multicast behavior is inconsistent

This monitoring is what makes Engage so powerful for AV installations:
You don’t have to guess why multicast is behaving oddly — you can see it.

How to Design a Stable Querier Architecture Using Engage

Here is the recommended design for predictable IGMP querier behavior in AV networks:

Step 1 — Choose one switch per AV VLAN as the querier

Typically the core or a switch that is always powered on.
Mark it as the “Planned Querier” in Engage for visual reference.

Step 2 — Give this switch the lowest IP address in the VLAN

This is the only way to guarantee it will win the IGMP election.

Step 3 — Enable Election Participate on that switch

So it properly participates in the election and maintains querier status.

Step 4 — Assign higher IP addresses to all other switches

This ensures they will never win the election.

Step 5 — Optionally disable Election Participate on edge switches

This prevents them from ever becoming querier, even momentarily.

This structure eliminates querier instability — one of the most common causes of unpredictable multicast behavior.

Why Engage Sometimes Appears to Behave Differently Than Expected

Because many engineers assume Engage forces querier behavior.
It does not.

Engage:

• Marks your intended querier
• Shows you the actual querier
• Helps you verify architectural intent
• Visualizes IGMP behavior

But IGMP always follows the open standard:

The switch with the lowest IP address becomes the querier.

This is exactly why Jeroen observed that another switch — with a lower IP — still became the querier even though he selected “Planned Querier” in Engage.

Engage reflected this correctly.

Conclusion

NETGEAR Engage makes IGMP behavior understandable, predictable, and highly visible — but it does not alter the IGMP protocol itself.

If you want to ensure that your desired switch becomes and remains the querier, make sure to configure:

• IP planning
• Election Participate settings
• VLAN interface addressing
• Consistent design across the network

Engage helps you validate and maintain this structure. You can douwload NETGEAR Engage for free via:  https://www.netgear.com/business/solutions/engage-controller/

👉 If you haven’t read it yet, What Is IGMP, Why Does It Sometimes Behave “Strangely”… and Why NETGEAR Developed IGMP Plus™ explains why IGMP sometimes behaves unpredictably and why IGMP Plus is essential in AV networks.

Eric Lindeman, NETGEAR ProAV Staff Systems Engineer Benelux

For more information about NETGEAR AV Switching, please contact the NETGEAR Pro AV Design Team via email: ProAVdesign@netgear.com

If you’d like to delve deeper into AV over IP switching, I invite you to check out our Online Academy via the link: https://academy.netgear.com/

On our training portal, you can find both AV and IT-related training courses. These courses are free to attend after registration, and at the end of each course, you can take an exam to earn a certificate.