Huawei Quidway S5600 Series - Ip Multicast Protocols

Operation Manual – Multicast Protocol
Quidway S5600 Series Ethernet Switches-Release 1510 Chapter 1 Multicast Overview
Huawei Technologies Proprietary
1-9
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:
XXXXX
25bit MAC address prefix
XXXXXXXX XXXXXXXX XXXXXXXX1110XXXX
XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
32-bit IP address
48-bit MAC address
23bit
mapping
Five bits are lost
XXXXX
25bit MAC address prefix
XXXXXXXX XXXXXXXX
XXXXX
25-bit MAC address prefix
XXXXXXXX XXXXXXXX XXXXXXXX1110XXXX
XXXXXXXX
XXXXXXXX1110XXXX
XXXXXXXX XXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
23-bit
mapping
XXXXX
25bit MAC address prefix
XXXXXXXX XXXXXXXX
XXXXX
25bit MAC address prefix
XXXXXXXX XXXXXXXX XXXXXXXX1110XXXX
XXXXXXXX
XXXXXXXX1110XXXX
XXXXXXXX XXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
32-bit IP address
48-bit MAC address
23bit
mapping
Five bits are lost
XXXXX
25bit MAC address prefix
XXXXXXXX XXXXXXXX
XXXXX
25-bit MAC address prefix
XXXXXXXX XXXXXXXX XXXXXXXX1110XXXX
XXXXXXXX
XXXXXXXX1110XXXX
XXXXXXXX XXXXXXXX XXXXXXXXXXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
XXXXXXXX XXXXXXXX XXXXXXXX
…… ……
23-bit
mapping
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
Multicast
User D
User E
User C
IGMP
IGMP
User A
User B
IGMP
MBGP/MSDP
PIM
PIM
AS1
AS2
Figure 1-6 Positions of protocols related to multicast