# IGMP: Report suppression detected on VLAN 100, multicast group 239.1.1.1

- **ID:** `networking/igmp-report-supression`
- **Domain:** networking
- **Category:** protocol_error
- **Verification:** ai_generated
- **Fix Rate:** 78%

## Root Cause

Multiple hosts on the same VLAN are suppressing IGMP reports due to a misconfigured querier, causing the multicast router to lose group membership information and stop forwarding traffic.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Cisco IOS 15.7(3)M | active | — | — |
| Juniper Junos 21.4R2 | active | — | — |
| Linux kernel 5.15.0-91-generic | active | — | — |
| Arista EOS 4.29.1F | active | — | — |

## Workarounds

1. **Configure IGMP snooping querier on the VLAN to ensure consistent query generation: `ip igmp snooping querier 10.0.100.1`** (85% success)
   ```
   Configure IGMP snooping querier on the VLAN to ensure consistent query generation: `ip igmp snooping querier 10.0.100.1`
   ```
2. **Enable IGMP explicit host tracking to bypass report suppression: `ip igmp snooping explicit-tracking`** (90% success)
   ```
   Enable IGMP explicit host tracking to bypass report suppression: `ip igmp snooping explicit-tracking`
   ```
3. **Set the IGMP query interval to a lower value (e.g., 60 seconds) to reduce suppression window: `ip igmp query-interval 60`** (75% success)
   ```
   Set the IGMP query interval to a lower value (e.g., 60 seconds) to reduce suppression window: `ip igmp query-interval 60`
   ```

## Dead Ends

- **** — This floods all multicast traffic to all ports, defeating the purpose of snooping and causing unnecessary bandwidth consumption. (70% fail)
- **** — Longer intervals actually increase the chance of suppression because hosts wait longer to respond, and the querier may time out before receiving reports. (60% fail)
- **** — Static entries do not account for dynamic group changes and require manual updates, leading to stale or missing entries. (80% fail)