This causes a 32-to-1 IP multicast address-to-multicast MAC address ambiguity (25 = 32).
- Chapter 2. Network Access and Layer 2 Multicast
- from IP Multicast, Volume 1: Cisco IP Multicast Networking
- Publisher: Cisco Press
- Released: October 2016
23 bits of Multicast class D is used to identify the Mac Address of the multicast group.
Because the high order 4 bits of class D address is '1110' for all multicast groups, we will have 5 bits of the layer 3 address with no effect on identifying the Mac address.
5 bits represent 32 numbers, so 32 multicast group gets a single Mac address.
1 Mac -> 32 Multicast address
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