Netgear GS728TP GS728TP/GS728TPP/GS752TP Software Administration Manual - Page 111

GS752TP, GS728TP, and GS728TPP Gigabit Smart Switches the Layer 2 LAN interface from its forwarding table entry upon receiving an IGMP leave message for that Multicast group without first sending out MAC-based general queries to the interface. You should enable fast leave admin mode only on VLANs where only one host is connected to each Layer 2 LAN port. This mode prevents the inadvertent dropping of the other hosts that were connected to the same Layer 2 LAN port but were still interested in receiving multicast traffic directed to that group. Also, fast leave processing is supported only with IGMP version 2 hosts. • Host Timeout. The value for group membership interval of IGMP snooping for the specified VLAN ID. This value is calculated as follows: (Query Interval * 2) + Maximum Response Time. • Maximum Response Time. Enter the amount of time in seconds that a switch waits after sending a query on the VLAN because it did not receive a report for a particular group in that interface. The valid range is 5-20 seconds. This value must be less than the Host Timeout value. • MRouter Timeout. The amount of time that a switch waits to receive a query on the VLAN before removing it from the list of VLANs with multicast routers attached. This value is calculated as follows: Query Interval * 2. • Query Mode. Enable or disable the IGMP querier mode for the specified VLAN ID. • Query Interval. Enter the value for IGMP query interval for the specified VLAN ID. The valid range is 30-1800 seconds. The default is 60 seconds. 3. Click APPLY to send the updated configuration to the switch. Configuration changes take place immediately. To disable IGMP snooping on a VLAN and remove it from the list, select the check box next to the VLAN ID and click DELETE. IGMP Snooping Querier IGMP snooping requires that one central switch or router periodically query all end devices on the network to announce their Multicast memberships. This central device is the IGMP querier. The IGMP query responses, known as IGMP reports, keep the switch updated with the current multicast group membership on a port-by-port basis. If the switch does not receive updated membership information in a timely fashion, it stops forwarding multicast transmissions to the port where the end device is located. The screens you access from the IGMP Snooping Querier link enable you to configure and display information about IGMP snooping queriers on the network and, separately, on VLANs. The IGMP Snooping Querier feature contains links to features described in the following sections: • IGMP Snooping Querier Configuration • IGMP Snooping Querier VLAN Configuration • IGMP Snooping Querier VLAN Status Configuring Switching Information 111