Planet Technology SGSW-2402 - Manual (Page 19)

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Step 4: Click “Apply” button and save it if everything is OK.
NOTE
The screen is divided into two sections. Current Spanning Tree Root section displays the
read-only Spanning Tree settings for the current root switch and the parameters this switch is
to use when it becomes the root switch.
3.8 IGMP
Internet Group Management Protocol (IGMP) is an Internet protocol that provides a way for an
Internet computer to report its multicast group membership to adjacent routers. It allows the
management switch to forward multicast traffic intelligently. The switch "snoops" the IGMP query and
report messages and forwards traffic to only the ports that request the multicast traffic. This prevents
the switch from broadcasting the traffic to all ports and
possibly affecting network performance.
The membership of a host group is dynamic - hosts may join
and leave groups at any time. There is no restriction on the
location or number of members in a host group. A host may
be a member of more than one group at a time. A host need
not be a member of a group to send datagrams to it.
Figure 3-7 The IGMP Screen page
3.8.1 IGMP Management
To activate IGMP function,
Step 1: Select “enabled” in the IGMP state field.
Step 2: Click on the radio button to select the version for IGMP.
Step 3: Hit on the “Apply” button and save your setting.
3.8.2 Definition on IGMP v1.0 and v2.0
For IGMP v1.0,
The Internet Group Management Protocol (IGMP v1.0) is used by IP hosts to report their host group
memberships to any immediately neighboring multicast routers. IGMP is an asymmetric protocol and
is specified here from the point of view of a host, rather than a multicast router.
NOTE
IGMPv1 has no leave mechanism. If a host no longer wants to receive the traffic, it simply
quits. If it is the last, the router will not have any answers to its query and will delete the GDA
for that subnet.
For IGMP v2.0,
IGMP v2.0 allows group membership termination to be quickly reported to the routing protocol, which is
important for high-bandwidth multicast groups and/or subnets with highly volatile group membership.
Host Group Addresses
Host groups are identified by class D IP
addresses, i.e., those with "1110" as their
high-order four bits. Class D IP addresses,
i.e., those with "1111" as their high-order
four bits, are reserved for future addressing
modes.
In Internet standard "dotted decimal"
notation, host group addresses range from
224.0.0.0 to 239.255.255.255. The address
224.0.0.0 is guaranteed not to be assigned
to any group, and 224.0.0.1 is assigned to
the permanent group of all IP hosts
(including gateways). This is used to
address all multicast hosts on the directly
connected network. There is no multicast
address (or any other IP address) for all
hosts on the total Internet. The addresses of
other well-known, permanent groups are to
be published in "Assigned Numbers".