Implementation and application of fast leave of S series switches

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For an S series switch, the fast leave function is configured using the igmp-snooping prompt-leave command (for Layer 2 multicast) or the igmp prompt-leave command (for Layer 3 multicast). If this function is not configured, the switch sends a Group-Specific Query message in response to an IGMP Leave message to check whether there are other users in the group specified in the Leave message. After fast leave is configured, the switch directly deletes the interface that receives the IGMP Leave message from the multicast forwarding entry, and does not check whether there are still users in the group.
The fast leave function is applicable only to interfaces with only one user attached. If fast leave is configured on an interface connecting to multiple users, multicast traffic of all users under the interface is interrupted when one user switches to another channel.

Other related questions:
How do I configure fast leave of a member port on an S series switch
The prompt leave function enables the switch to delete the multicast forwarding entry of a multicast group from an interface immediately after the interface receives an IGMP Leave message for the group. This function saves bandwidth and system resources because the switch does not need to wait until the aging timer of the interface expires. For S series switches excluding the S1700, to enable fast leave of a member port in VLAN 10, perform the following configurations: [HUAWEI] igmp-snooping enable //Enable IGMP snooping globally. [HUAWEI] vlan 10 [HUAWEI-vlan10] igmp-snooping enable //Enable IGMP snooping in VLAN 10. [HUAWEI-vlan10] igmp-snooping prompt-leave //Enable fast leave of a member port in VLAN 10.

What are the working mechanism and usage scenario of fast leave
The fast leave function is configured using the igmp-snooping prompt-leave command (for Layer 2 multicast) or the igmp prompt-leave command (for Layer 3 multicast). If this function is not configured, the switch sends a Group-Specific Query message in response to an IGMP Leave message to check whether there are other users in the group specified in the Leave message. After fast leave is configured, the switch directly deletes the interface that receives the IGMP Leave message from the multicast forwarding entry, and does not check whether there are still users in the group. The fast leave function is applicable only to interfaces with only one user attached. If fast leave is configured on an interface connecting to multiple users, multicast traffic of all users under the interface is interrupted when one user switches to another channel.

How do S series switches implement fast switchover when RRPP is deployed
For S series switches, fast RRPP switchover is guaranteed by the switchover mechanism, which is irrelevant to the interval for sending Hello packets. Although the minimum interval for sending Hello packets is 1s, Hello packets are used only for loop detection. The following is the switchover mechanism of an RRPP ring: - If a link in the ring is faulty, the port directly connected to the link goes Down. - The transit node immediately sends a Link-Down packet to the master node to report the link status change. - When receiving the Link-Down packet, the master node considers that the ring fails, so it unblocks the secondary port and sends a packet to instruct other transit nodes to update Forwarding DataBases (FDBs). - After other transit nodes refresh their FDBs, the data stream is switched to a link in the Up state.

Whether the S-series switches support fast forwarding
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