Enabling fast leave for IGMP V2
device immediately stops forwarding traffic to the interface. This feature requires the entire VLAN be configured for IGMP V3 with no IGMP V2 clients. If a client does not send a report during the specified group membership time (the default is 260 seconds), that client is removed from the tracking list.
Every group on a physical port keeps its own tracking record. However, it can only track group membership; it cannot track by (source, group). For example, Client A and Client B belong to group1 but each receives traffic streams from different sources. Client A receives a stream from (source_1, group1) and Client B receives a stream from (source_2, group1). The device still waits for the configured
To enable the tracking and fast leave feature for VLAN 20, enter the following commands.
device(config)#vlan 20
Syntax: [no] multicast tracking
The membership tracking and fast leave features are supported for IGMP V3 only. If any port or any client is not configured for IGMP V3, then the multicast tracking command is ignored.
Enabling fast leave for IGMP V2
When a device receives an IGMP V2 leave message, it sends out multiple
To configure fast leave for IGMP V2, enter the following commands.
device(config)#vlan 20
Syntax: [no] multicast fast-leave-v2
Enabling fast convergence
In addition to sending periodic general queries, an active device sends general queries when it detects a new port. However, because the device does not recognize the other device's port up event, multicast traffic might still require up to the
If the Layer 2 protocol cannot detect a topology change, fast convergence may not work in some cases. For example, if the direct connection between two devices switches from one interface to another, the rapid spanning tree protocol (802.1w) considers this optimization, rather than a topology change. In this example, other devices will not receive topology change notifications, and will be unable to send queries to speed up the convergence. Fast convergence works well with the regular spanning tree protocol in this case.
To enable
device(config)#vlan 70
FastIron Ethernet Switch IP Multicast Configuration Guide | 25 |
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