677
response time of the host to group query message.
The main features of version3 is allowing the host to choose receiving from or
rejecting a certain source, which is the basis of SSM
（
Source-Specific Multicast
）
multicast. For example, when a host is sending a report of INCLUDE{10.1.1.1, 10.1.1.2}
to some group G, that means the host needs the router to forward the flux from 10.1.1.1
and 10.1.1.2; when a host is sending a report of EXCLUDE{192.168.1.1} to some group
G, that means the host needs the flux from all sources of group G except 192.168.1.1.
This makes a great difference from the previous IGMP.
The main improvements of IGMP version3 over IGMP version1 are:
1. The status to be maintained is group and source list, not only the groups in IGMPv2.
2. The interoperations with IGMPv1 and IGMPv2 are defined in IGMPv3 status.
3. IP service interface is modified to allow specific source list thereby.
4. The queried includes his/her Robustness Variable and Query Interval in query group
to allow the synchronization with these variables of non-queries.
5. Max Response Time in Query Message has an exponential range, with maximum
value from 25.5 secs of v2 to 53 mins, which can be used in links of great capacity.
6. In order to increase strength, the host retransmits State-Change message.
7. Additional data is defined to adapt future extension.
8. Report group is sent to 224.0.0.22 to help with IGMP Snooping of Layer 2 Switch.
9. Report group can include more than one group record, and it allows using small
group to report complete current status.
10. The host does not restrain operation any more, which simplifies the implement and
allows direct membership trace.
11. In querying messages, the new router side restraint process (S sign) modified the
existing strength of IGMPv2.
17.6.2 Configuration Task List
1
、
Enable IGMP (Required)
2
、
Configure IGMP sub-parameters (Optional)
（
1
）
Configure IGMP group parameters
1
）
Configure IGMP group filtering conditions
2
）
Configure IGMP to join in group
3
）
Configure IGMP to join in static group
（
2
）
Configure IGMP query parameters
1
）
Configure the interval of IGMP sending query message
2
）
Configure the maximum response time of IGMP query
3
）
Configure time-out of IGMP query
（
3
）
Configure IGMP version
