#Multicast mac address converter plus

#Multicast mac address converter plus

xxxx x- 5 remaining bits after the 23bits of the IP address is mapped to the MAC address plus the 4 high order bits 1110.1110 - First 4 high-order bits of the IP address for the multicast address space (224.x.x.x).Take the low order 23 bits from step 2 and plug it into the low-order 23 bits of the IP address (do this in binary):.Isolate the 23 low-order binary bits from the converted MAC address:.HereвЂ™s a breakdown of the conversion bit by bit:.Convert the hexadecimal MAC address 01:00:5e:0a:00:01 to binary.LetвЂ™s start by using the example MAC address given in the book : 01:00:5e:0a:00:01 The following is an example of how we arrive with those 32 IP addresses that map to a single MAC address:ДЇor reference, use the following conversion chart for converting hex to binary and vice versa If you happened to be studying for BSCI, I am referring to the section of the BSCI: Authorized Self-Study Guide, by Teare and Paquet, that starts on page 598 - 600. So I went about researching how it was done. The problem is, the book does not explain or show how it solved the mapping. With the 5 bits of extra overlap, there are 32 (2 5 = 32) IP multicast address that map to one MAC multicast address.But remember, 23 low-order bits out of the 28 available bits are mapped to the MAC address, giving us 5 remaining bits of overlap.

With 32 total bits present in an IP address and 4 high order bits of it set at 1110, we are left with 28 bits of unique IP addresses we can use (32 - 4 = 28).

The high order 4 bits of the Layer 3 IP address is fixed to 1110to indicate the Class D address space between 224.0.0.0 through 239.255.255.255.

In order to achieve the translation between a Layer 3 IP multicast address and Layer 2 multicast MAC address, the low-order 23 bits of the IP address (Layer 3) is mapped into the low-order 23 bits of the MAC address (Layer 2).

In the course of reading through the BSCI authorize self-study guide, IвЂ™ve come across a multicast example where the author talks about the concepts behind the multicast IP to MAC address mapping. Map Multicast MAC address to IP Multicast Addresses