Ip Multicast Protocols - Huawei Quidway S5600 Series Operation Manual

Operation Manual – Multicast Protocol
Quidway S5600 Series Ethernet Switches-Release 1510
As stipulated by IANA, the high-order 24 bits of a multicast MAC address are 0 x
01005e, while the low-order 23 bits of a MAC address are the low-order 23 bits of the
multicast IP address. Figure 1-5 describes the mapping relationship:
48-bit MAC address 48-bit MAC address
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
Figure 1-5 Mapping relationship between multicast IP address and multicast MAC
address
The high-order four bits of the IP multicast address are 1110, representing the multicast
ID. Only 23 bits of the remaining 28 bits are mapped to a MAC address Thus five bits of
the multicast IP address are lost. As a result, 32 IP multicast addresses are mapped to
the same MAC address.

1.2.2 IP Multicast Protocols

IP multicast protocols include the multicast group management protocol and the
multicast routing protocol. Figure 1-6 describes the positions of the protocols related to
multicast in the network.
Server
Figure 1-6 Positions of protocols related to multicast
1110XXXX 1110XXXX 1110XXXX 1110XXXX 1110XXXX 1110XXXX 1110XXXX
32-bit IP address 32-bit IP address
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
25bit MAC address prefix 25bit MAC address prefix 25bit MAC address prefix 25-bit MAC address prefix 25bit MAC address prefix 25bit MAC address prefix 25-bit MAC address prefix
Multicast
AS2
Huawei Technologies Proprietary
Five bits are lost Five bits are lost
XXXXX XXXXX XXXXX XXXXX XXXXX XXXXX XXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
...... ...... ...... ...... ...... ......
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
AS1
IGMP
PIM
MBGP/MSDP
IGMP
PIM
IGMP
User E
1-9
Chapter 1 Multicast Overview
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
23-bit 23-bit 23bit 23bit
...... ...... ...... ...... ...... ......
mapping mapping
mapping mapping
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
User A
User B
User C
User D