Edge-Core ECS3510-10PD Management Manual page 627

The default values recommended in the MRD draft are implemented
N :
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in the switch.
Multicast Router Discovery uses the following three message types to
discover multicast routers:
Multicast Router Advertisement – Advertisements are sent by routers to
◆
advertise that IP multicast forwarding is enabled. These messages are
sent unsolicited periodically on all router interfaces on which multicast
forwarding is enabled. They are sent upon the occurrence of these
events:
Upon the expiration of a periodic (randomized) timer.
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As a part of a router's start up procedure.
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During the restart of a multicast forwarding interface.
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On receipt of a Solicitation message.
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◆ Multicast Router Solicitation – Devices send Solicitation messages in
order to solicit Advertisement messages from multicast routers. These
messages are used to discover multicast routers on a directly attached
link. Solicitation messages are also sent whenever a multicast
forwarding interface is initialized or re-initialized. Upon receiving a
solicitation on an interface with IP multicast forwarding and MRD
enabled, a router will respond with an Advertisement.
◆ Multicast Router Termination – These messages are sent when a router
stops IP multicast routing functions on an interface. Termination
messages are sent by multicast routers when:
Multicast forwarding is disabled on an interface.
■
An interface is administratively disabled.
■
The router is gracefully shut down.
■
Advertisement and Termination messages are sent to the All-Snoopers
multicast address. Solicitation messages are sent to the All-Routers
multicast address.
MRD messages are flooded to all ports in a VLAN where IGMP
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snooping or routing has been enabled. To ensure that older switches which
do not support MRD can also learn the multicast router port, the switch
floods IGMP general query packets, which do not have a null source
address (0.0.0.0), to all ports in the attached VLAN. IGMP packets with a
null source address are only flooded to all ports in the VLAN if the system is
operating in multicast flooding mode, such as when a new VLAN or new
router port is being established, or an spanning tree topology change has
occurred. Otherwise, this kind of packet is only forwarded to known
multicast routing ports.
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| Multicast Filtering
C 17
HAPTER
Layer 2 IGMP (Snooping and Query for IPv4)