STRIDE SE-MC2U-SC, User Manual

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Static Router:
Specifies whether the switch should assume there is an IGMP router on this
port even if no IGMP query messages are received.
IGMP Example
The Benefits of Enabling IGMP:
Take an already established control network that has an Ethernet device sending multicast
data to several other Ethernet devices. Between the source of the multicast data, and the
destination Ethernet devices that are interested in the multicast data, multicast packets might
pass through a number of switches or routers.
To make this control network more efficient, the switches or routers should know how
to handle the flow of multicast data by means of IGMP (Internet Group Management
Protocol). Switches or routers that are not capable of supporting IGMP will not know what
to do with the multicast data and forward multicast data out all ports. This will slow down
the network.
Take a look at the following diagram, where the IGMP server is the source of the multicast
data, and the IGMP hosts are the devices interested in receiving multicast data. On the
network are two switches, where one has IGMP enabled and the other has IGMP disabled.
We see that the switch with IGMP enabled only forwards multicast data to the interested
host (Ethernet Station 2). The switch with IGMP disabled will not know where to send
the multicast data; thus Ethernet Stations 4 and 6 unnecessarily receive multicast data even
though only Station 5 is the interested host.
Managed
Switch
Managed
Switch
IGMP
Server
Ethernet Station 1
Ethernet Station 3
Ethernet Station 2
(IGMP Host)
Ethernet Station 4
Ethernet Station 6
Ethernet Station 5
(IGMP Host)
Multicast Traffic
– IGMP enabled
– IGMP disabled
4-39
Chapter 4 - Managed Switch Software Setup
Stride Industrial Ethernet Switches User Manual 2nd Ed. Rev. A