Registering Group Members - Fujitsu XG Series User Manual

XG Series User's Guide
4.8.1

Registering Group Members

On receiving an IGMP Report message, the device registers a multicast MAC address to the IGMP snooping control table
for the port that received the IGMP Report message and the connecting multicast router port.
XG
IGMP Report
IGMP Report
MAC : 0100.5E01.0203
MAC : 0100.5E01.0203
Destination IP : 239.1.2.3
Source IP Destination IP : 239.1.2.3
: 192.168.10.20
Group IP : 239.1.2.3
Group IP : 239.1.2.3
• The device can register multicast groups up to a maximum value (Reference
Note
Multicast packets that cannot be registered are those flooding all ports belonging to the same VLAN.
• If "igmpsnoop unknown flooding off" command is set, Multicast packets that cannot be registered are those not flooding all
ports belonging to the same VLAN (XG0224, XG0448).
The following figure shows the relationship between the registered IP multicast address and the multicast MAC address.
MAC addresses that are registered with IGMP snooping are between 0100.5E00.0000 and 0100.5E7F.FFFF. An IP
multicast address is 32 bits. The first 4 bits are always 1110 followed by 28 bits that represent the IP multicast address
information. Of these 28 bits, the lower order 23 bits are mapped to a MAC address and the data in the higher order 5 bits
is not used.
Therefore 32 IP multicast addresses are mapped to the same single MAC address.
IP Multicast Address
0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1
Multicast MAC Address
VLAN 10
Port 8
Port 1 Port 2
Terminal 1
Terminal 2

Registering Group Members

1 1 1 0 1 1 1 0 1 1 1 1 1 1 1 1
Class D
Reserved for IPv4 Multicast
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 1 0 0 1 0 1 1 1 1 0
0 1 0 0 . 5 E 0 1 . 0 2 0 3
0 1 0 0 . 5 E
Multicast Address
Multicast Router
IGMP snooping Control Table MAC Address Table
VLAN Port
VLAN(RouterPort)
0100.0501.0203 Group IP 1, 8
(01:00:05:01:02:03)
10 (8) 239.1.2.3
Port 3
Terminal 3
"1.2.3 System Maximum Values"
239. 239. 1. 2. 3 1. 2. 3
0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0
5 Bit Loss
Lower 23 Bit Mapping
0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0
78
Chapter 4 Switch Functions and their Configuration
(MAC address) Port Reporter
1 192.168.10.20
(pg.34)).
0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 1
0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 1
IGMP Snooping