42
IGMP C
ONFIGURATION
IGMP Overview
Introduction to IGMP
Internet Group Management Protocol (IGMP) is a protocol in the TCP/IP suite
responsible for management of IP multicast members. It is used to establish and
maintain multicast membership among IP hosts and their directly connected
neighboring routers. IGMP excludes transmitting and maintenance of membership
information among multicast routers, which are completed by multicast routing
protocols. All hosts participating in multicast must implement IGMP.
Hosts participating in IP multicast can join and leave a multicast group at any time.
The number of members of a multicast group can be any integer and the location
of them can be anywhere. A multicast router does not need and cannot keep the
membership of all hosts. It only uses IGMP to learn whether receivers (i.e., group
members) of a multicast group are present on the subnet connected to each
interface. A host only needs to keep which multicast groups it has joined.
IGMP is not symmetric on hosts and routers. Hosts need to respond to IGMP query
messages from the multicast router, i.e., report the group membership to the
router. The router needs to send membership query messages periodically to
discover whether hosts join the specified group on its subnets according to the
received response messages. When the router receives the report that hosts leave
the group, the router will send a group-specific query packet (IGMP Version 2) to
discover whether no member exists in the group.
Up to now, IGMP has three versions, namely, IGMP Version 1 (defined by
RFC1112), IGMP Version 2 (defined by RFC2236) and IGMP Version 3. At present,
IGMP Version 2 is the most widely used version.
IGMP Version 2 boasts the following improvements over IGMP Version 1:
Election mechanism of multicast routers on the shared network segment
A shared network segment means that there are multiple multicast routers on a
network segment. In this case, all routers running IGMP on the network segment
can receive the membership report from hosts. Therefore, only one router is
necessary to send membership query messages. In this case, the router election
mechanism is required to specify a router as the querier.
In IGMP Version 1, selection of the querier is determined by the multicast routing
protocol. While IGMP Version 2 specifies that the multicast router with the
smallest IP address is elected as the querier when there are multiple multicast
routers on the same network segment.
Summary of Contents for Switch 8807
Page 14: ......
Page 32: ...32 CHAPTER 2 COMMAND LINE INTERFACE...
Page 50: ...50 CHAPTER 5 MANAGEMENT INTERFACE CONFIGURATION...
Page 54: ...54 CHAPTER 6 CONFIGURATION FILE MANAGEMENT...
Page 64: ...64 CHAPTER 8 SUPER VLAN CONFIGURATION...
Page 70: ...70 CHAPTER 9 ISOLATE USER VLAN CONFIGURATION...
Page 78: ...78 CHAPTER 10 IP ADDRESS CONFIGURATION...
Page 82: ...82 CHAPTER 11 IP PERFORMANCE CONFIGURATION flag ACK window 16079...
Page 100: ...100 CHAPTER 13 ETHERNET PORT CONFIGURATION...
Page 114: ...114 CHAPTER 15 PORT ISOLATION CONFIGURATION...
Page 158: ...158 CHAPTER 18 DIGEST SNOOPING CONFIGURATION...
Page 162: ...162 CHAPTER 19 FAST TRANSITION...
Page 219: ......
Page 220: ...220 CHAPTER 24 VLAN ACL CONFIGURATION...
Page 234: ...234 CHAPTER 25 802 1X CONFIGURATION...
Page 284: ...284 CHAPTER 28 IP ROUTING PROTOCOL OVERVIEW...
Page 290: ...290 CHAPTER 29 STATIC ROUTE CONFIGURATION...
Page 338: ...338 CHAPTER 31 OSPF CONFIGURATION...
Page 392: ...392 CHAPTER 33 BGP CONFIGURATION...
Page 404: ...404 CHAPTER 34 IP ROUTING POLICY CONFIGURATION...
Page 406: ...406 CHAPTER 35 ROUTE CAPACITY CONFIGURATION...
Page 408: ...408 CHAPTER 36 RECURSIVE ROUTING CONFIGURATION...
Page 416: ...416 CHAPTER 37 IP MULTICAST OVERVIEW...
Page 430: ...430 CHAPTER 39 IGMP SNOOPING CONFIGURATION...
Page 454: ...454 CHAPTER 42 IGMP CONFIGURATION...
Page 462: ...462 CHAPTER 43 PIM DM CONFIGURATION...
Page 506: ...506 CHAPTER 46 MBGP MULTICAST EXTENSION CONFIGURATION...
Page 528: ...528 CHAPTER 48 MPLS BASIC CAPABILITY CONFIGURATION...
Page 632: ...632 CHAPTER 51 MPLS VLL...
Page 652: ...652 CHAPTER 52 VPLS CONFIGURATION...
Page 666: ...666 CHAPTER 53 VRRP CONFIGURATION...
Page 680: ...680 CHAPTER 56 ARP TABLE SIZE CONFIGURATION...
Page 718: ...718 CHAPTER 59 NETSTREAM CONFIGURATION...
Page 728: ...728 CHAPTER 61 POE CONFIGURATION...
Page 736: ...736 CHAPTER 63 UDP HELPER CONFIGURATION...
Page 746: ...746 CHAPTER 64 SNMP CONFIGURATION...
Page 792: ...792 CHAPTER 68 FILE SYSTEM MANAGEMENT...
Page 800: ...800 CHAPTER 69 DEVICE MANAGEMENT...
Page 810: ...810 CHAPTER 70 FTP TFTP CONFIGURATION...
Page 840: ...840 CHAPTER 72 SYSTEM MAINTENANCE AND DEBUGGING...
Page 844: ...844 CHAPTER 74 PACKET STATISTICS CONFIGURATION...
Page 846: ...846 CHAPTER 75 ETHERNET PORT LOOPBACK DETECTION...
Page 860: ...860 CHAPTER 76 QINQ CONFIGURATION...
Page 866: ...866 CHAPTER 77 NQA CONFIGURATION...
Page 876: ...876 CHAPTER 78 PASSWORD CONTROL CONFIGURATION...