Chapter 4: Web-Based Management
GE-DS-242-PoE Managed Ethernet Switch User Manual
93
IGMP Versions 1 and 2
Multicast groups allow members to join or leave at any time. IGMP provides the
method for members and multicast routers to communicate when joining or leaving
a multicast group.
IGMP version 1 is defined in RFC 1112. It has a fixed packet size and no optional data.
The format of an IGMP packet is shown below:
IGMP Message Format
Octets
0
8 16
31
Type Response
Time
Checksum
Group Address (all zeros if this is a query).
The IGMP Type codes are shown below:
Type Meaning
0x11
Membership Query (if Group Address is 0.0.0.0).
0x11
Specific Group Membership Query (if Group Address is Present).
0x16
Membership Report (version 2).
0x17
Leave a Group (version 2).
0x12
Membership Report (version 1).
IGMP packets enable multicast routers to keep track of the membership of multicast
groups, on their respective sub networks. The following outlines what is
communicated between a multicast router and a multicast group member using
IGMP.
A host sends an IGMP "report" to join a group.
A host will never send a report when it wants to leave a group (for version 1).
A host will send a "leave" report when it wants to leave a group (for version 2).
Multicast routers send IGMP queries (to the all-hosts group address: 224.0.0.1)
periodically to see whether any group members exist on their sub networks. If there is
no response from a particular group, the router assumes that there are no group
members on the network.
Summary of Contents for GE-DS-242-POE
Page 1: ...GE Security P N 1069174 REV 1 0 ISS 22FEB10 GE DS 242 PoE Managed Ethernet Switch User Manual ...
Page 14: ...Chapter 1 Introduction 10 GE DS 242 PoE Managed Ethernet Switch User Manual ...
Page 124: ...Chapter 4 Web Based Management 120 GE DS 242 PoE Managed Ethernet Switch User Manual ...
Page 130: ...Chapter 5 Console Management 126 GE DS 242 PoE Managed Ethernet Switch User Manual ...
Page 204: ...Chapter 8 Power Over Ethernet Overview 200 GE DS 242 PoE Managed Ethernet Switch User Manual ...
Page 210: ......