IGMP/MLD
IGMP/MLD Overview
Multicast delivers IP packets to a group of hosts on the network defined by multicast groups. Membership to these multicast groups are established using IGMP/MLD.
Use the IGMP/MLD screen to configure IGMP/MLD group settings.
What You Need To Know
Multicast and IGMP
See Multicast for more information.
Multicast Listener Discovery (MLD)
The Multicast Listener Discovery (MLD) protocol (defined in RFC 2710) is derived from IPv4's Internet Group Management Protocol version 2 (IGMPv2). MLD uses ICMPv6 message types, rather than IGMP message types. MLDv1 is equivalent to IGMPv2 and MLDv2 is equivalent to IGMPv3.
• MLD allows an IPv6 switch or router to discover the presence of MLD hosts who wish to receive multicast packets and the IP addresses of multicast groups the hosts want to join on its network.
• MLD snooping and MLD proxy are analogous to IGMP snooping and IGMP proxy in IPv4.
• MLD filtering controls which multicast groups a port can join.
• An MLD Report message is equivalent to an IGMP Report message, and an MLD Done message is equivalent to an IGMP Leave message.
IGMP Fast Leave
When a host leaves a multicast group (224.1.1.1), it sends an IGMP leave message to inform all routers (224.0.0.2) in the multicast group. When a router receives the leave message, it sends a specific query message to all multicast group (224.1.1.1) members to check if any other hosts are still in the group. Then the router deletes the host’s information.
With the IGMP fast leave feature enabled, the router removes the host’s information from the group member list once it receives a leave message from a host and the fast leave timer expires.
The IGMP/MLD Screen
Use this screen to configure multicast groups that the Zyxel Device manages through IGMP/MLD settings. To open this screen, click Network Setting > IGMP/MLD.
Some models only support IGMP/MLD Default Version configuration.For DX3300/3301-T0, IGMP/MLD are enabled by default and are not configurable. The default IGMP version is 3. The default MLD version is 2.Network Setting > IGMP/MLD
The following table describes the labels in this screen.
Label | Description |
|---|---|
IGMP/MLD Configuration | |
Default Version | Enter the version of IGMP (1~3) and MLD (1~2) that you want the Zyxel Device to use on the WAN. |
Query Interval | Enter the number of seconds the Zyxel Device sends a query message to hosts to get the group membership information. |
Query Response Interval | Enter the maximum number of seconds the Zyxel Device can wait for receiving a General Query message. Multicast routers use general queries to learn which multicast groups have members. |
Last Member Query Interval | Enter the maximum number of seconds the Zyxel Device can wait for receiving a response to a Group-Specific Query message. Multicast routers use group-specific queries to learn whether any member remains in a specific multicast group. |
Robustness Value | Enter the number of times (1~7) the Zyxel Device can resend a packet if packet loss occurs due to network congestion. |
Maximum Multicast Groups | Enter a number to limit the number of multicast groups an interface on the Zyxel Device is allowed to join. Once a multicast member is registered in the specified number of multicast groups, any new IGMP or MLD join report frames are dropped by the interface. |
Maximum Multicast Data Sources(for IGMPv3) | Enter a number to limit the number of multicast data sources (1-24) a multicast group is allowed to have. The setting only works for IGMPv3 and MLDv2. |
Maximum Multicast Group Members | Enter a number to limit the number of multicast members a multicast group can have. |
Fast Leave Enable | Select this option to set the Zyxel Device to remove a port from the multicast tree immediately (without sending an IGMP or MLD membership query message) once it receives an IGMP or MLD leave message. This is helpful if a user wants to quickly change a TV channel (multicast group change) especially for IPTV applications. |
LAN to LAN (Intra LAN) Multicast Enable | Select this to enable LAN to LAN IGMP snooping capability. |
Membership Join Immediate (IPTV) | Select this to have the Zyxel Device add a host to a multicast group immediately once the Zyxel Device receives an IGMP or MLD join message. |
Cancel | Click Cancel to exit this screen without saving. |
Apply | Click Apply to save your changes back to the Zyxel Device. |