Edge-Core ECS3510-10PD, Management Manual

Page: 1218 / 1494

C
HAPTER
38
| Multicast Filtering Commands
IGMP Snooping
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C
OMMAND
U
SAGE
◆
When a multicast host leaves a group, it sends an IGMP leave message.
When the leave message is received by the switch, it checks to see if
this host is the last to leave the group by sending out an IGMP group-
specific or group-and-source-specific query message, and starts a
timer. If no reports are received before the timer expires, the group
record is deleted, and a report is sent to the upstream multicast router.
◆
A reduced value will result in reduced time to detect the loss of the last
member of a group or source, but may generate more bursty traffic.
◆
This command will take effect only if IGMP snooping proxy reporting is
enabled ( page 1208 ).
E
XAMPLE
Console(config)#ip igmp snooping vlan 1 last-memb-query-intvl 700
Console(config)#
ip igmp snooping
vlan mrd
This command enables sending of multicast router solicitation messages.
Use the no form to disable these messages.
S
YNTAX
[ no ] ip igmp snooping vlan vlan-id mrd
vlan-id - VLAN ID (Range: 1-4094)
D
EFAULT
S
ETTING
Disabled
C
OMMAND
M
ODE
Global Configuration
C
OMMAND
U
SAGE
◆
Multicast Router Discovery (MRD) uses multicast router advertisement,
multicast router solicitation, and multicast router termination messages
to discover multicast routers. 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.
◆
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 expiration of a periodic timer, as a part of a router's
start up procedure, during the restart of a multicast forwarding
interface, and on receipt of a solicitation message. When the multicast
services provided to a VLAN is relatively stable, the use of solicitation