|
0 |
7 15 |
31 | ||||
|
Type |
Max. Resp Code |
Checksum | ||||
|
Group Address | ||||||
|
Resv |
S |
QRV |
QQIC |
Number of Sources (N) | ||
|
Source Address [1] Source Address [N] | ||||||
Figure 4.1 IGMPv3 message format
Where
- Type: The message type ( 0x11 JoinM , 0x17 LeaveM )
- Max. Resp. Code: specifies the maximum time allowed before sending a responding
message, (Used only for JoinM message).
- Checksum: The checksum for messages errors.
- Group Address: The group address the receiver is joining or leaving for JoinM or
LeaveM messages.
- Resv: Reserved. Set to 0 on transmission and ignored when reception.
- Number of Sources (N): Number of source addresses in this message.
- Source Address [1..N]: The IP address(s) the message is sending to.
The IGMPv3 messages are restricted for the communication between the receivers and the
LMRs. To transmit the information included in these two previous messages to the source,
new pair of messages are created at LMRs; Registration request Message (RqM) and
Registration reply Message (RpM).
These messages may be updated at BNRs. RqM messages are created on behalf of joining a
new group member in the multicast group and sent to the source. The source upon receiving
this message will reply by RpM to the message sender. A detailed explanation about the role
of these messages in joining and leaving process will be discussed later in this chapter.
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