Chapter 33 IGMP
XGS-4728F User’s Guide
288
IGMP (Internet Group Management Protocol) is used by multicast hosts to indicate
their multicast group membership to multicast routers. Multicast routers can also
use IGMP to periodically check if multicast hosts still want to receive transmission
from a multicast server. In other words, multicast routers check if any hosts on
their network are still members of a specific multicast group.
The Switch supports IGMP version 1 (
IGMP-v1
), version 2 (
IGMP-v2
)
and IGMP
version 3 (IGMP-v3). Refer to RFC 1112, RFC 2236 and RFC 3376 for information
on IGMP versions 1, 2 and 3 respectively. At start up, the Switch queries all
directly connected networks to gather group membership. After that, the Switch
periodically updates this information.
33.1.1 How IGMP Works
This section describes how IGMP works and the changes it has gone through from
version 1 to version 3. IGMP version 1 defines how a multicast router checks to
see if any multicast hosts are part of a multicast group. It checks for group
membership by sending out an IGMP Query packet. Hosts that are members of a
multicast group reply with an IGMP Report packet. This is also referred to as a join
group request. The multicast router then keeps a list of all networks that have
members of this multicast group and forwards multicast traffic to that network.
Figure 156
IGMP Version 1 Example
The main difference in IGMP version 2 is that it provides a mechanism for a
multicast group member to notify a multicast router that it is leaving a multicast
group. The multicast router then sends a group-specific IGMP query to check if
there are any members remaining in that group. If the multicast router does not
receive an IGMP report from any members, it stops sending multicast traffic to
that group. This change helps shorten the leave convergence time, in other words,
the amount of time that a multicast router believes that there are group members
2 Report
1 Query
Summary of Contents for XGS-4728F
Page 2: ......
Page 8: ...Safety Warnings XGS 4728F User s Guide 8 ...
Page 24: ...24 ...
Page 30: ...Chapter 1 Getting to Know Your Switch XGS 4728F User s Guide 30 ...
Page 34: ...Chapter 2 Hardware Installation and Connection XGS 4728F User s Guide 34 ...
Page 42: ...Chapter 3 Hardware Overview XGS 4728F User s Guide 42 ...
Page 44: ...44 ...
Page 78: ...Chapter 7 System Status and Port Statistics XGS 4728F User s Guide 78 ...
Page 92: ...Chapter 8 Basic Setting XGS 4728F User s Guide 92 ...
Page 94: ...94 ...
Page 114: ...Chapter 9 VLAN XGS 4728F User s Guide 114 ...
Page 118: ...Chapter 10 Static MAC Forward Setup XGS 4728F User s Guide 118 ...
Page 148: ...Chapter 14 Bandwidth Control XGS 4728F User s Guide 148 ...
Page 162: ...Chapter 17 Link Aggregation XGS 4728F User s Guide 162 ...
Page 186: ...Chapter 21 Policy Rule XGS 4728F User s Guide 186 ...
Page 230: ...Chapter 25 AAA XGS 4728F User s Guide 230 ...
Page 268: ...268 ...
Page 324: ...324 ...
Page 332: ...Chapter 38 Maintenance XGS 4728F User s Guide 332 ...
Page 358: ...Chapter 41 Syslog XGS 4728F User s Guide 358 ...
Page 366: ...Chapter 42 Cluster Management XGS 4728F User s Guide 366 ...
Page 370: ...Chapter 43 MAC Table XGS 4728F User s Guide 370 ...
Page 374: ...Chapter 44 IP Table XGS 4728F User s Guide 374 ...
Page 378: ...Chapter 46 Routing Table XGS 4728F User s Guide 378 ...
Page 382: ...382 ...
Page 392: ...Chapter 48 Troubleshooting XGS 4728F User s Guide 392 ...
Page 402: ...Chapter 49 Product Specifications XGS 4728F User s Guide 402 ...
Page 404: ...404 ...
Page 408: ...Appendix A Legal Information XGS 4728F User s Guide 408 ...